JPH0427648Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a printing unit of a gravure printing press, and more particularly to a piping device used for automatically cleaning the plate cylinder and ink pan within the printing unit.

BACKGROUND OF THE INVENTION Traditionally, printing plate cylinders have been manually cleaned by operators at each printing unit. Further, ink pan cleaning is carried out by removing the ink pan and related piping from each unit, transporting it to a cleaning site, and cleaning the ink pan manually or using a cleaning device. however,
These operations are hard and time-consuming operations, and the vapors of the cleaning solvent are often inhaled during the operations, which is unfavorable from a sanitary standpoint. As a result of various studies on streamlining and automating such cleaning work, the inventors of the present invention have found that good cleaning is possible by sealing the ink pan and plate cylinder in the printing unit and spraying cleaning liquid onto the plate cylinder and ink pan. We have discovered that cleaning can be automated.

Problems that the invention aims to solve: However, when cleaning plate cylinders or ink pans using this method, the solvent used as the cleaning liquid is sprayed through a nozzle, so there is a risk of explosion as there are many parts that vaporize. When the seal was later released, the vaporized solvent inside would spread to the surrounding area, causing a problem in that it would worsen the surrounding environment.

The present invention aims to solve these problems by preventing the risk of explosion when spraying cleaning liquid into a sealed plate cylinder or ink pan, and also by preventing too much solvent vapor from leaking outside when the seal is released. The purpose is to provide a piping device to prevent this from occurring.

Means for Solving the Problems The present invention, which has been devised to achieve the above objects, includes an ink pan sealing device that seals the upper opening of the ink pan, and a cleaning liquid spray nozzle disposed in the space sealed by the ink pan sealing device. A printing unit of a gravure printing press having a pump having a suction side connected to a new cleaning liquid supply source and a discharge side connected to the injection nozzle, and a cleaning liquid return pipe connected to a lower part of an ink pan and a suction side of the pump. , an exhaust pipe connected to the cleaning liquid return pipe, a waste cleaning liquid discharge pipe connected between the discharge side of the pump and the injection nozzle, and an inert gas supply pipe for supplying inert gas to the injection nozzle. The gist of the present invention is a piping device for a printing unit characterized by having:

Function When cleaning the plate cylinder or ink pan, first seal the plate cylinder and ink pan, and then supply an inert gas such as carbon dioxide to the injection nozzle from the inert gas supply pipe, and inject carbon dioxide into the closed space through the nozzle. The air in the system is replaced with carbon dioxide gas. This lowers the oxygen concentration in the system and prevents the risk of explosion even if the solvent is injected. The plate cylinder or ink pan is cleaned by spraying fresh cleaning liquid from a nozzle, and then circulating the cleaning liquid accumulated at the bottom of the ink pan using a pump and spraying it from the nozzle. Therefore, the amount of cleaning liquid used can be reduced. After cleaning, the solvent vapor in the system is sufficiently exhausted through the exhaust pipe, and then the seal is released. This prevents leakage of solvent vapor into the surrounding atmosphere.

Embodiments Hereinafter, preferred embodiments of the present invention shown in the drawings will be described.

In FIG. 1, 1 is a unit frame of a printing unit, 2 is an ink pan, and 3 is a plate cylinder. The unit frame 1 is provided with projecting portions 4 facing each other, and the ink pan 2 is pressed against the lower surface of the projecting portion 4 and sealed. A suitable plate or sheet material 5 is disposed on the outer periphery of the overhanging portion 4 so as to be openable and closable, and constitutes an ink pan sealing device. A large number of spray nozzles 6 for spraying cleaning liquid onto the plate cylinder 3 are provided on the inner surface of the ink pan sealing device.
Furthermore, a spray nozzle 7 is provided above the ink pan 2 for spraying a cleaning liquid onto the inner surface of the ink pan. The injection nozzle 7 is normally housed within the projecting portion 4, but is connected to a drive mechanism 8 such as an air cylinder so that it can be moved to the position shown in the figure after the plate cylinder is removed. A connecting pipe 10 is connected to the bottom of the ink pan 2, and the connecting pipe 10 is connected to an ink circulation system 9 including an ink pump 11 and a filter 12.
The ink circulation system 9 extracts ink from the bottom of the ink pan during printing and supplies it to the plate cylinder 3. A drain pipe 13 is also connected to the connecting pipe 10.

The injection nozzles 6 and 7 are connected to the discharge side of a pump 22 via a filter 21 by a pipe 20. The suction side of the pump 22 is connected to a new cleaning liquid supply source through a pipe 23, and is also connected to the connecting pipe 10 at the bottom of the ink pan 2 through a cleaning liquid return pipe 24. The cleaning liquid return pipe 24 is further connected to an exhaust device (not shown) by an exhaust pipe 25. on the other hand,
A waste cleaning liquid discharge pipe 26 is provided in a branched manner on the projecting side of the pump 22 and is connected to a waste cleaning liquid reservoir. Furthermore, an inert gas supply pipe 2 connected to an inert gas supply source is connected to the pipe 20 between the pump 22 and the nozzle.
7 is connected. In this embodiment, carbon dioxide gas is used as the inert gas, and the supply pipe 27 will be referred to as the carbon dioxide gas supply pipe 27 hereinafter. As the pump 22 used here, a gear pump is preferable so that the pressure and discharge amount necessary for injection by the nozzles 6 and 7 can be secured. In addition, in the figure, A indicates an automatic valve, and M indicates a manual valve.

Next, the operation of the above device will be explained. After printing is finished,
An ink pan sealing device surrounds and seals the upper part of the ink pan and the plate cylinder. At this time, the nozzle 7 is housed within the projecting portion 4. First, residual ink is drained from the drain pipe 13 at the bottom of the ink pan. Next, carbon dioxide gas is supplied from the carbon dioxide supply pipe 27 and injected into the sealed ink pan through the nozzle 6 to lower the oxygen concentration in the ink pan. This avoids the risk of explosion when spraying cleaning fluids such as solvents. After carbon dioxide gas is injected, while slowly rotating the plate cylinder 3, fresh cleaning liquid is supplied to the nozzle 6 by the pump 22 and sprayed onto the plate cylinder from the nozzle 6 to clean the plate cylinder. After continuing cleaning with the new cleaning liquid for some time, the supply of the new cleaning liquid is stopped, and the captain's liquid accumulated in the ink pan 2 is supplied to the nozzle 6 by the pump 22 to continue cleaning the plate cylinder. When the cleaning liquid becomes dirty, the cleaning liquid in the ink pan is discharged from the system as waste cleaning liquid, and the plate cylinder is cleaned again with new cleaning liquid. After repeating this operation appropriately, the cleaning liquid in the ink pan is discharged as waste cleaning liquid, and the cleaning of the plate cylinder by the nozzle 6 is completed.

Next, the inside of the ink pan 2 is evacuated via the exhaust pipe 25 and the cleaning liquid return pipe 24 to exhaust the solvent vapor in the system. After exhausting the solvent vapor, the ink pan sealing device is opened or the ink pan 2 is lowered to release the ink pan seal, and the plate cylinder 3 is removed. Next, the ink pan 2 is again sealed with the ink pan sealing device, and the nozzle 7 is moved to the illustrated position. after that,
Carbon dioxide gas is supplied from the carbon dioxide gas supply pipe 27 and injected into the system from the nozzle 6 or nozzle 7. Next, the pump 22 is operated to supply new cleaning liquid to the nozzle 7, and the cleaning liquid is sprayed from the nozzle 7 onto the inner surface of the ink pan to clean the ink pan. After a certain period of time has elapsed, the supply of new cleaning liquid is stopped, and the cleaning liquid in the ink pan is circulated by the pump 22 to continue cleaning the ink pan. At the same time, the ink pump 11 of the ink circulation system 9 is operated to pass the cleaning liquid in the ink pan into the ink circulation system 9, thereby cleaning the ink circulation system 9 as well. When the cleaning liquid becomes dirty, it is discharged as waste cleaning liquid, cleaning is started again with new cleaning liquid, and the same scanning is repeated, thereby cleaning the ink pan and the ink pan circulation system. After cleaning the ink pan and ink circulation system, the cleaning liquid is discharged as waste cleaning liquid, and the system is then evacuated to release the ink pan seal and prepare for installation of a new plate cylinder.

Although the above-mentioned embodiment is for cleaning both the plate cylinder and the ink pan, the present invention is not necessarily limited to this case, and may be applied to cleaning only one of them.

Effects of the Invention As described above, according to the present invention, inert gas (carbon dioxide gas in the embodiment) can be injected into a sealed ink pan, thereby preventing the risk of explosion when spraying cleaning liquid. Further, since the inside of the sealed ink pan can be evacuated, exhausting the air before unsealing the ink pan prevents solvent vapor from leaking to the surrounding area, thereby preventing deterioration of the working environment. Furthermore, inert gas injection is performed using a cleaning liquid injection nozzle, and exhaust is performed using a cleaning liquid return pipe. There is no need to provide piping or ports, and there is no need to complicate the ink pan or ink pan sealing device.

[Brief explanation of the drawing]

FIG. 1 is a schematic piping diagram showing an embodiment of the present invention. 2... Ink pan, 3... Plate cylinder, 6, 7... Injection nozzle, 9... Ink circulation system, 22... Pump, 24... Cleaning liquid return pipe, 25... Exhaust pipe, 2
6...Waste cleaning liquid discharge pipe, 27...Inert gas supply pipe.

Claims (1)

[Scope of utility model registration request] In a printing unit of a gravure printing press, the upper opening of the ink pan is connected to an ink pan sealing device, and a cleaning liquid injection nozzle is placed in a space sealed by the ink pan sealing device. a pump whose side is connected to the injection nozzle, a cleaning liquid return pipe connected to a lower part of the ink pan and the suction side of the pump, an exhaust pipe connected to the cleaning liquid return pipe, and a discharge side of the pump and the injection nozzle. A piping device for a printing unit, comprising: a waste cleaning liquid discharge pipe connected between the two, and an inert gas supply pipe for supplying inert gas to the injection nozzle.