JPH10157078A - Ink recovering and cleaning device for flexographic printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To largely shorten a time for recovery of ink and cleaning water with a simple structure and to save ink. SOLUTION: This device forcibly sucks so as not to retain ink and cleaning water in an ink reservoir. As its sucking means, an air ejector 23 for injecting the compressed air to suck it into the reservoir 30 with its accompanying flow to vacuum is used, the injection of the air is controlled by switching a solenoid valve 26, thereby facilitating intermittent suctions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of applying a quick-drying flexo ink from an ink reservoir provided around an anilox roll to the peripheral surface of the roll, and then transferring the ink to a printing plate wound around a print cylinder. In a flexographic printing press that prints on corrugated cardboard, when exchanging ink, the ink remaining in the ink circulation path is quickly recovered even if the circulation pump is stopped, and then the anilox roll is supplied by supplying washing water. The present invention relates to an ink collecting and cleaning apparatus for cleaning the ink circulation path including a peripheral surface.

[0002]

2. Description of the Related Art In general, for printing on a corrugated cardboard sheet, a quick-drying flexographic ink which can be connected to a die cutter or a folder gluer in a later process is used. This ink is water-soluble and can be washed relatively easily by flowing washing water when replacing the ink. In recent years, as the number of products has been reduced to smaller lots, frequent order changes have been required, and there has been a strong demand for shortening the ink exchange time accompanying order changes in order to improve productivity. Therefore, an ink recovery apparatus for quickly recovering and cleaning ink in a flexographic printing machine is disclosed in Jitsuho 3-334.
No. 72, Japanese Utility Model Laid-Open No. 4-128840, and the like.

[0003] In brief, the above-mentioned prior art is described in Japanese Utility Model Publication No. 3-33472, in which several suction nozzles are provided at intervals above an ink reservoir so as to be vertically movable. The tip of each nozzle enters and exits the ink reservoir, and the residual ink is collected from the suction nozzle by a vacuum pump. The vacuum pump is connected via a sealed container for air / water separation, and the ink collected in the sealed container for air / water separation is collected by another pump into a tank for printing ink.

Japanese Patent Laid-Open Publication No. 4-128840 discloses a vacuum pump which receives ink overflowing from an end of an ink reservoir between an anilox roll and a rubber roll with a pan, and is attached to a closed tank. To collect the ink.

[0005]

However, in any case, a mechanical pump is used as a vacuum pump for recovering ink and washing water, and a sufficient suction force is exerted. There is a problem in that there is a driving part, which vibrates or requires maintenance. Further, the former is provided with a sealed container for water / water separation, and is provided with another pump for collecting from the inside of the container into the ink tank, which is very expensive in terms of cost.
Even if a vacuum pump is directly provided in the sealing means for sealing the ink tank as in the latter case, the mechanical pump takes a long time to start and stop, and is not suitable for intermittent use.

[0006] In addition, the ink reservoir is elongated so as to cover the entire width of the anilox roll, and as the amount of ink and washing water staying therein decreases, the outflow to the end pan becomes slower and it takes time to collect the ink. In order to solve the problem that a small amount of ink and washing water always remain without flowing out near the center of the ink reservoir and cannot be collected, in the former case, the natural fall from the ink reservoir must be Instead of waiting, several suction nozzles were used to forcibly suck up, but the structure was complicated.

[0007]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides an ink collecting and cleaning apparatus which has a simple structure, can greatly reduce the time for collecting ink and washing water, and can save ink. The ink is forcibly sucked so that the ink and the washing water do not remain in the ink reservoir, and as a suction means, compressed air is blown out, and the ink is sucked into the ink reservoir with its accompanying flow to form a vacuum. The air ejector described above is used, and the ejection of the compressed air is controlled by opening and closing an electromagnetic valve so that intermittent suction can be easily performed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a flexographic printing press in which ink is circulated by a circulation pump between an anilox roll and an ink reservoir formed by pressing a doctor roll or a doctor blade against the roll and an ink reservoir, an ink reservoir is provided. An air ejector connected to a source of pressurized air via a solenoid valve is attached to the lid together with a supply pipe connected to the circulation pump and a recovery pipe connected to the ink reservoir, and the lid is appropriately attached. It can be moved up and down by simple driving means. Then, a driving means for horizontally moving the lid is provided so that the lid can be placed on the drainage storage tank placed near the ink storage section.

A main suction pipe is provided vertically above the ink reservoir so as to be vertically movable, and a plurality of suction nozzles are attached to the main suction pipe at appropriate intervals. It is preferable to connect the collection pipe to the approximate center of the suction main pipe.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
1 and 2 are connected by a and b respectively, the flexographic printing press shown in this figure is configured to print on the lower surface of a corrugated cardboard sheet, and is imprinted on the peripheral surface of the anilox roll 1. The flexo ink supplied to the provided recess is transferred to the printing plate 3 wound on the print cylinder 2 and printed on the lower surface of the corrugated cardboard sheet 5 conveyed between the press roll 4. The anilox roll 1 is supplied with ink from an ink reservoir 7 which is formed above the doctor roll 6 pressed against the roll. The ink reservoir 7 is disposed downstream of the solenoid valve 32 from the ink tank 20 via the supply pipe 12 via the circulation pump 40.

The solenoid valve 32 can interrupt the flow in the ink circulation path. A vent 30 is provided on the upstream side via the electromagnetic valve 32 via the electromagnetic valve 31, and washing water is supplied on the downstream side via the electromagnetic valve 33. Has become the highest point.

Above the ink reservoir 7, a plurality of suction nozzles 9 are provided at appropriate intervals in the main suction tube 10 so as to point toward the ink reservoir 7, and the main suction tube is vertically movable. Both ends are attached to the air cylinders 11, 11,
The tip of the suction nozzle 9 moves in and out of the ink reservoir. The suction nozzle 9 is made of a flexible material, and its tip is formed in a V-shape according to the V-shape of the cross section of the ink reservoir.

Receiving trays 8 for receiving ink overflowing from the ink reservoirs 7 are provided below both ends of the ink reservoirs, and a collection pipe 13 is connected from each receiving tray to the ink tank 20. A collection pipe 14 that joins the collection pipe 13 is connected to substantially the center of the suction main pipe 10. Solenoid valves 34 and 35 are provided on the recovery pipes 13 and 14 upstream of the merging section, respectively, so that the suction sections can be switched.

The lid 21 is attached to the air cylinder 36 so as to be able to move up and down. Furthermore, this air cylinder 3
6 is attached to a rotary air cylinder 37 fixed to the machine base 50 so as to be rotatable in the horizontal direction. Therefore, the lid 21 can be moved vertically and horizontally. The lid 21 is placed on the ink tank 20 at the time of printing and ink recovery by such a driving means, and is placed on the drainage storage tank 25 described later at the time of washing.

The ink tank 20 is positioned by being brought into contact with a stopper 38 and mounted on a machine base 50. Similarly, a drainage storage tank 25 is positioned and mounted in the vicinity thereof.

As shown in FIG. 3, the end of a supply pipe 12 provided with a filter 15 is
Each pipe is attached so that it is disposed near the inner bottom surface and the tip of the collection pipe 13 is disposed above the tank so as to be away from the ink surface.

Further, an air ejector 23 connected to a compressor 27 via an electromagnetic valve 26 is attached to the lid 21. In this method, the inside of the ink tank is evacuated by ejecting compressed air from the nozzle 24 to suction and collect ink or washing water in the ink reservoir. The suction can be easily controlled by opening and closing the solenoid valve 26. . Here, the compressor (pressure air generation source) 27 may use an existing device, and does not need to be newly provided. As described above, the air ejector is a very lightweight and compact device with a simple structure, does not vibrate, and requires only a small lid driving means for automating ink exchange, and the entire device is compact. Therefore, it is possible to easily modify an existing printing press.

In the flexographic printing press having the above configuration, during normal printing, the solenoid valves 32 and 34 are opened and the other solenoid valves are closed, and as shown by the arrow in FIG. The ink sucked up from the ink tank 20 is supplied to the upper portion of the pressure contact between the anilox roll 1 and the doctor roll 6 to form the ink reservoir 7. Then, the ink is constantly circulated in a path of overflowing from the ink reservoir 7 to the tray 8 and being stored again in the ink tank 20.

When the flexographic printing press is configured to print on the lower surface of the sheet, if the height of the tray 8 is lower than the ink level of the ink tank 20, the ink in the tray is forcibly collected. However, if the air ejector 23 is used, it is possible to easily and intermittently suck the air in accordance with the flow rate. If the height of the receiving tray 8 is higher than the ink level, the ink naturally circulates in the collection pipe, so that such an operation is unnecessary.

When changing ink, first, the circulation pump 4
0 is stopped, and the ink stays in the ink circulation path. Then, the suction main pipe 10 is lowered by the air cylinder 11, and the tip of the suction nozzle 9 is sunk into the ink reservoir 7. When the ventilation solenoid valve 31 is opened from this state, the ink in the supply pipe 12 and the circulation pump 40 naturally falls into the ink tank 20 on the downstream side and falls into the ink reservoir on the upstream side. At the same time, when the electromagnetic valve 26 for compressed air injection is opened, the ink tank 20 and the collection pipe 1 are opened by the air ejector 23.
The ink inside the ink reservoir is sucked from the suction nozzle 9 and collected into the ink tank 20 while the ink overflowing from the ink reservoir 7 to the receiving tray 8 is also collected.

Here, since a plurality of suction nozzles 9 are provided, a small amount of ink is recovered almost without remaining in the ink reservoir, and the recovery pipe 14 is provided.
Is connected to substantially the center of the main suction pipe 10, and the suction can be performed more uniformly than when it is connected to one end, so that the time is slightly shortened. Even if air is mixed with the ink, the ink is stored in the ink tank 20 and only the air is discharged from the discharge port 22 to the outside. When ink runs out, solenoid valve 2
6 is closed and the ink collecting operation is completed.

Next, at the time of cleaning, the air cylinder 36 and the rotary air cylinder 37 are driven to put the lid 21 on the drainage storage tank 25. Thereafter, the electromagnetic valve 31 for ventilation is closed, and the electromagnetic valve 33 for supplying cleaning water is opened, and cleaning water is introduced. Here, the washing water is separated into two parts, passes through the circulation pump 40 and the ink reservoir 7, respectively, to wash the inside of the pipe, and is stored in the drainage tank 25. At the same time, the anilox roll 1 and the doctor roll 6 are rotated at a low speed, whereby the washing water accumulated in the ink reservoir 7 is used to wash the ink adhering to the surfaces of both rolls. Washing in the circulation pump 40 requires only a small amount of washing water, and water can be saved by closing the electromagnetic valve 32 after an appropriate time has elapsed.

After washing for a predetermined time, the washing water supply solenoid valve 33 is closed, and the washing water staying in the ink circulation path is collected in the same manner as when the ink is collected. It is preferable that the drainage tank 25 has a small volume because the suction time is reduced. Thus, the cleaning operation is completed. If the ink tank 20 is replaced so that it is placed in contact with the stopper 38 during this time, the lid 21 is again placed on the new ink tank by the driving means, and the ink replacement operation is completed.

In the case of a blade type flexographic printing press, the same effect can be obtained by suctioning the ink from the ink reservoir formed by the anilox roll and the doctor blade with an air ejector.

[0025]

As described in detail above, the present invention is configured so that ink and washing water are sucked by an air ejector utilizing compressed air, so that only opening and closing of a solenoid valve connected to the air ejector is controlled. The start and stop of suction can be easily and instantly switched, and the ink remaining in the ink reservoir and the cleaning water are forcibly suctioned without waiting for the water to overflow into the pan. Water collection can be promoted, and the ink exchange time can be further reduced, contributing to an improvement in productivity.

The air ejector itself is a very compact device, does not vibrate, can be easily moved even when it is attached to the lid, and a suction nozzle is provided in the suction main pipe provided across the width of the machine for suctioning the ink reservoir. Since it is directly mounted, it can be constructed at a low cost with a simple structure as a whole.

Furthermore, since the amount of ink and washing water remaining in the ink reservoir can be minimized, the efficiency of ink recovery is improved, the amount of expensive flexo ink used is reduced, and printing costs are saved, and This has the effect of reducing the occurrence of defective products due to the denaturation of the ink at the next printing, and performing stable and high-quality printing.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of an ink collecting and cleaning apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view of an ink recovery apparatus according to an embodiment of the present invention.

FIG. 3 is a cross-sectional view of an ink storing section according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anilox roll 6 Doctor roll 9 Suction nozzle 10 Suction main pipe 11 Air cylinder 12 Supply pipe 13, 14 Recovery pipe 20 Ink tank 21 Lid 23 Air ejector 26 Solenoid valve 27 Compressor 36 Air cylinder 37 Rotary air cylinder 40 Circulation pump

Claims (4)

[Claims] 1. A flexographic printing machine in which an ink is circulated by a circulation pump between an anilox roll and an ink reservoir formed by pressing a doctor roll or a doctor blade against the roll and an ink reservoir, the ink reservoir is hermetically sealed. An air ejector connected to a pressure air source via an electromagnetic valve is attached to the lid together with a supply pipe connected to the circulation pump and a recovery pipe connected to the ink reservoir, and the lid is appropriately driven. An ink recovery and cleaning device in a flexographic printing press, wherein the device can be moved up and down by means. 2. The ink collecting and cleaning apparatus in a flexographic printing press according to claim 1, further comprising a driving means for horizontally moving a lid so as to be mounted on a drainage storage tank mounted near the ink storage section. 3. The flexographic printing method according to claim 1, wherein a main suction pipe is vertically movable along the ink reservoir and a plurality of suction nozzles are attached to the main suction pipe at appropriate intervals. Collection and cleaning equipment in the machine. 4. The ink recovery and cleaning device in a flexographic printing press according to claim 3, wherein a recovery pipe is connected to substantially the center of the suction main pipe.