JPH11105251A - Method and apparatus for printing corrugated fiberboard with gloss on print surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a print surface by coating the surface with ultraviolet curable transparent paint in a thin film-like state, and instantaneously drying the coating layer of the paint by emitting an ultraviolet ray thereto, thereby giving gloss to the surface of normal ink. SOLUTION: A print surface of a corrugated fiberboard sheet is coated with ultraviolet curable varnish by rotating a coating roll 33. Since the coating surface of the varnish is instantaneously dried by an ultraviolet emitting unit 5, printed fiberboard sheets can be immediately stuck, or served for bending and sizing for case-manufacturing. Waste of transferring the sheet by a long conveyor after printing to gain time until the ink is dried can be eliminated. The unit 5 is obtained by longitudinally slidably suspending boxes 51 containing ultraviolet lamps on rails 52 provided in a frame 50 via hanging rolls 53 provided at its upper end.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing method and a printing apparatus which can impart gloss to a printing surface and protect the printing surface in printing on a corrugated cardboard sheet.

[0002]

2. Description of the Related Art Inks used for printing corrugated cardboard sheets are roughly classified into four types. The first is a high-viscosity pre-slot printing ink which has a high viscosity and is difficult to dry but has a glossy printing surface. Ink for flexographic printing which is low in dryness and easy to dry but has no gloss on the printed surface. In recent years, this third type of new ink has become the mainstream of corrugated cardboard sheet printing. The fourth is an ultraviolet curable ink that can provide a glossy printed surface. Hereinafter, the three types of inks except the ultraviolet curable ink are referred to as ordinary inks.

[0003]

The printing surface made of the above-mentioned UV-curable ink makes the printed portion stand out, and gives rise to a considerable aesthetic appearance, to the extent that it is better than the printing surface made of other inks. Had insufficient gloss. or,
All of the ink adhering portions on the corrugated cardboard sheet had gloss, and it was not possible to give gloss to only the portion of the printed portion that was desired to be emphasized and to make it stand out. Further, the ultraviolet curable ink is expensive, and printing all of the printed portion with the ultraviolet curable ink increases the printing cost.

In view of the above circumstances, an object of the present invention is to solve the following three problems. The first problem is to provide gloss to the printing surface with ordinary ink and protect the printing surface. The second problem is to give gloss only to a necessary portion of a print portion. The third challenge is
The purpose is to further impart gloss to the printing surface using the ultraviolet curable ink.

[0005]

The cardboard sheet printing method of the present invention comprises applying a UV-curable transparent paint (hereinafter, referred to as UV-curable varnish or simply varnish) to a required portion of a printing surface in a thin film form by a printing technique. The method is characterized in that the varnish coating layer is instantaneously dried by ultraviolet irradiation. Specifically, a pair of sump rolls (31) and (32) are disposed facing each other with their peripheral surfaces in contact with each other, and a pair of weir plates (38) provided across both the sump rolls (31) and (32). The ultraviolet curable varnish is stored in a liquid reservoir (39) formed between the liquid reservoir rolls (31) and (32) and the peripheral surface of the liquid reservoir rolls (31) and (32). The varnish is transferred to a coating roll (33) provided in contact with the liquid storage roll (31) or a plate removably attached to the roll (33), and the coating roll (33) is rotated to rotate the varnish onto the printing surface of the corrugated cardboard sheet. Apply varnish.

In the corrugated cardboard sheet printing apparatus of the present invention, an ultraviolet-curable transparent paint coating device (3) (hereinafter simply referred to as a varnish coating device) is provided downstream of the last-stage printing unit (1). An ultraviolet irradiation device (5) downstream of the coating device (3)
Is provided, and the varnish coating device (3) is provided with a pair of liquid storage rolls.
(31), (32) and a pair of weir plates (38) that are provided across the sump rolls (31), (32) to form a sump (39) between the sump rolls (31), (32). ) (38) and an application roll (33) which is provided in contact with one of the sump rolls (31) and rotates in synchronization with the plate cylinder (13) of the printing unit (1), or detachable from the roll (33). It is composed of a plate mounted as possible and a receiving roll (34) arranged opposite to the coating roll (33).

[0007]

[Functions and Effects] By applying an ultraviolet curable varnish to the printing surface using ordinary ink, gloss can be given to the printing surface and the appearance can be improved. In addition, by covering the printed portion with a varnish layer, the printed portion can be protected. The gloss obtained by applying the UV-curable varnish is superior to the printed surface only printed with the UV-curable ink. This is because when light is specularly reflected by the UV-curable varnish layer and the specularly reflected light enters the human eye,
It is considered that the varnish layer serves as a transparent specular reflector. If a UV curable varnish is applied to the surface to be printed with the UV curable ink, the gloss of the printed surface is further increased.

[0008] Since the ultraviolet curable varnish can be applied to the required portion of the print surface, the print surface can be partially conspicuous by the gloss, and the entire print surface can be made to look like the ultraviolet curable ink. Is more effective than a glossy case. Further, the printing cost can be reduced as compared with the case where the entire printing surface is printed with the ultraviolet curable ink.

The application of the ultraviolet curable varnish is performed by a varnish coating device (3) disposed downstream of the printing unit in the final stage, and the varnish coating device (3) includes a pair of liquid storage rolls (31).
Liquid pool (39) formed between (32) and a pair of weir plates (38)
To store the UV-curable varnish in the application roll (33) provided in contact with one of the liquid storage rolls (31), that is, from the liquid storage rolls (31) (32), the application roll (33) or To transfer the ultraviolet curable varnish to the plate detachably mounted on the roll (33), and to further transfer this to a corrugated cardboard sheet,
It can be applied neatly without spots.

Since the coating roll (33) rotates in synchronization with the plate cylinder (13) of the printing unit (1), the coating portion of the ultraviolet-curing varnish does not shift with respect to the printing surface without causing any displacement.
The transparent paint can be applied to the corrugated cardboard sheet immediately after printing at the same speed as the printing speed.

Since the coated surface of the UV-curable varnish is instantaneously dried by the UV irradiation device (5), the printed corrugated cardboard sheets can be immediately stacked, or subjected to bending and gluing for box making. Since the time until the printing ink dries is increased, it is possible to eliminate the waste of transferring the corrugated cardboard sheet by a long conveyor after printing.

[0012]

FIG. 1 shows a two-color printing apparatus. Two printing units (1) and (1a) are provided adjacent to the rail (10), and a varnish coating device (3) is disposed adjacent to the downstream printing unit (1). An ultraviolet irradiation device (5) is provided downstream. The printing unit (1) (1a), the varnish coating device (3), and the ultraviolet irradiation device (5) each have a mechanism built in a box-shaped frame (17) (17a) (37) (50). The frame (50) of the irradiation device (5) is fixed to the rail (10), and the other boxes (17), (17a) and (37) can slide the rail (10) independently. Therefore, two printing units
(1) Between (1a), between the downstream printing unit (1) and the varnish coating device (3), and between the varnish coating device (3) and the ultraviolet irradiation device
During (5), it can be opened for setup change or the like. In addition, when increasing the number of colors used for printing, a printing unit can be additionally provided on the rail (10).

Since the two printing units (1) and (1a) have the same configuration, the description will be made based on the downstream printing unit (1). In a plane parallel to the moving direction (right to left in FIG. 1) of the corrugated cardboard sheet, a pair of liquid storage rolls (11) and (12) are provided so as to be able to contact and separate at right angles to the moving direction.
One of the reservoir rolls (11) is an anilox roll having fine irregularities regularly formed on the surface, and the other is a hard rubber roll (12). A pair of weir plates (18) are provided between the two sump rolls (11) and (12), straddling the two rolls (11) and (12), and both rolls (11) (12) and the weir plate (18) are arranged. ), A liquid pool (19) is formed. The weir plate (18) may be slidably applied to the end surfaces of the rolls (11) and (12), or may be slidably provided on the peripheral surface of the rolls (11) and (12) to collect the liquid pool (19). May be adjustable.

The plate cylinder (13) is arranged below the anilox roll (11) in contact with the roll (11). A printing plate (not shown) made of synthetic resin is wound around the surface of the plate cylinder (13). A receiving roll (14) is provided below the plate cylinder facing the plate cylinder (13), and conveys the cardboard sheet between the plate cylinder (13) and the receiving roll (14) to the downstream side. Plate cylinder (13) and receiving roll (1
On the downstream side of 4), guide rolls (15) and (16) are provided with a transition path of the cardboard sheet interposed therebetween.

An ink supply / recovery device (2) is provided above the frame (17). The ink supply / recovery device (2) of the embodiment is a closed container as previously proposed and known by the applicant.
(24), a tank (21) housed in the closed container (24), and one end of the tank (21) hangs down from the inlet at the upper end of the tank (21) to the tank bottom,
The other end airtightly penetrates the closed container (24) and the liquid pool (19)
Tube (23) connected to the nozzle (22) located above the
It is constituted by and. The closed container (24) can be selectively switched between pressurized, depressurized and atmospheric pressure via a switching valve.

By supplying compressed air to the closed container (24) by switching the switching valve, the ink in the tank (21) is turned into a tube.
The liquid is discharged from the nozzle (22) to the liquid reservoir (19) through (23).
When the pressure in the closed vessel (24) is stopped by switching the switching valve to communicate with the atmosphere, the supply of the ink to the liquid reservoir (19) is stopped. The nozzle (22) is connected to an elevating device (not shown), and the nozzle (22) is lowered to the liquid reservoir (19), and the switching valve is switched to suck the inside of the closed container (21). (19)
Can be collected in the tank (21).

The varnish coating device (3) includes the printing unit
It has the same construction as (1), but the plate cylinder (13) of the printing unit (1)
In place of the application roll (33) in place of
The difference is that the collection device (2) is replaced with a varnish supply / collection device (4). The receiving roller (14) of the ink supply / recovery device (2)
Is the receiving roller (34) in the varnish coating device (3), the liquid collecting roller (12) is in the (32), the weir plate (18) is in the weir plate (38),
9) to the reservoir (39), tank (21) to the tank (41), nozzle (22) to the nozzle (42), tube (23) to the tube (43)
In addition, the closed container (24) is placed in the closed container (44), and the guide rollers (15) (1
In (6), the reference numerals for the guide rollers (35) and (36) are changed. The ultraviolet-curable transparent paint contained in the tank (41) of the varnish coating device (3) may be colorless and transparent, or may be colored and transparent such that the printed portion is visible even when applied over the printed portion. . The rotation drive mechanism is configured so that the respective feeding speeds of the corrugated cardboard sheets of the printing unit (1) and the varnish coating device (3), that is, the peripheral speeds of the plate cylinder (13) and the coating roll (33) are the same. ing.

In the printing section (7) shown in FIG. 2, when it is desired to give gloss only to a portion (8) surrounded by oblique lines, a coating roll (33)
Denotes a plate having a projection formed on the surface corresponding to the portion (8). As shown in FIG. 3, when a corrugated cardboard sheet (6) is provided with a glossy portion (8) in a strip shape including a printing portion (7), a convex portion is formed on an application roll (33) corresponding to the glossy portion. What is necessary is just to attach the version which did.

The ultraviolet irradiation device (5) is a box containing an ultraviolet lamp on a rail (52) provided in a frame (50).
(51) and (51) are suspended and slidable back and forth by suspending rolls (53) and (53) provided at the upper end thereof. The discharge conveyor (5) is sandwiched between the opening of the lower surface of the ultraviolet lamp storage box (51) and the 51
5) is deployed. Frame for the rail (52)
Connect the auxiliary rail (54) detachably from the outside of (50),
The ultraviolet lamp housing boxes (51) and (51) can be pulled out of the frame (50), and the ultraviolet lamp can be replaced.

However, by applying an ultraviolet curable varnish to the printing surface using ordinary ink, gloss can be given to the printing surface, the appearance can be improved, and the printing surface can be protected. If a UV curable varnish is applied to the surface to be printed with the UV curable ink, the gloss of the printed surface is further increased.

Since the UV curable varnish can be applied to the required portion of the print surface, the print surface can be partially made to stand out by gloss, and the entire print portion has a gloss like the print surface made of UV curable ink. It can alert you more effectively than in some cases. Further, the printing cost can be reduced as compared with the case where the entire printing section is printed with the ultraviolet curable ink.

An anilox roll (31) having fine irregularities on its surface among the two rolls (31) and (32) forming the liquid pool (39) of the apparatus (3) for applying an ultraviolet curable varnish. The application roll (33) was brought into contact with the anilox roll (31) by disposing the roll (33) in contact with the anilox roll (31).
The varnish accumulated in the fine dents of 1) is uniformly transferred to the plate of the application roll (33), and further transferred to the corrugated cardboard sheet, so that the required portion of the corrugated cardboard sheet can be applied neatly without unevenness. Since the coating roll (33) rotates in synchronization with the plate cylinder (13) of the printing unit (1), the coating portion of the ultraviolet curable varnish does not displace with respect to the printing portion, and the coating immediately after printing is performed. Varnish can be applied to the corrugated cardboard sheet at the same speed as the printing speed.

Since the coated surface of the UV-curable varnish is instantaneously dried by the UV irradiation device (3), the printed corrugated cardboard sheets can be immediately stacked or subjected to bending and gluing for box making. Since the time until the printing ink dries is increased, the waste of transporting the corrugated cardboard sheet by the long conveyor can be eliminated. The present invention is not limited to the configuration of the above embodiment, and various modifications are possible within the scope of the claims.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a printing apparatus.

FIG. 2 is a front view of a printing surface.

FIG. 3 is a front view of another embodiment of a printing surface.

[Explanation of symbols]

 (1) Printing unit (2) Ink supply / recovery device (3) Varnish application device (31) Liquid storage roll (32) Liquid storage roll (33) Application roll (4) Varnish supply / recovery device (5) Ultraviolet irradiation device (51) UV lamp storage box

Claims (3)

[Claims] 1. A glossy corrugated cardboard sheet characterized by applying an ultraviolet-curable transparent coating material to a required portion of a printing surface in a thin film form by a printing technique, and immediately drying the coated layer of the transparent coating material by ultraviolet irradiation. Printing method. 2. A pair of weir plates (38) provided with a pair of liquid storage rolls (31) and (32) facing each other with their peripheral surfaces in contact with each other, and provided across both liquid storage rolls (31) and (32). And both reservoir rolls (31) (32)
The UV curable transparent paint is stored in the liquid reservoir (39) formed between the liquid reservoir (39) and the liquid reservoir (39), and the two liquid reservoir rolls (31) and (32) are rotated to rotate to contact one of the liquid reservoir rolls (31). Application roll
(33) The gloss of transferring the UV-curable transparent paint to a plate detachably mounted on the roll (33), and applying the UV-curable transparent paint to the printing surface of the corrugated cardboard sheet by rotating the application roll (33). Corrugated sheet printing method. 3. An ultraviolet-curable transparent paint application device (3) is provided downstream of the last printing unit (1), and an ultraviolet irradiation device is provided downstream of the ultraviolet-curable transparent paint application device (3).
(5) is installed, UV curable transparent paint application device (3)
Is a pair of sump rolls (31) and (32) and a sump roll (31)
(32) A pair of weir plates (38) and (38) which are arranged across the gap and form a pool (39) between the pool rolls (31) and (32), and one of the pool rolls (31) Printing unit (1) provided in contact with
An application roll (33) that rotates in synchronization with the plate cylinder (13) or a plate detachably mounted on the roll (33), and the application roll (33)
And a receiving roll (34) arranged opposite to the coating roll.The ultraviolet curable transparent paint stored in the liquid pool (39) is applied to the application roll by rotating the liquid storage rolls (31) and (32) and the application roll (33). A printing apparatus for applying to a corrugated cardboard sheet passing between (33) and a receiving roll (34).