JP3592788B2 - How to change ink in flexographic printing press - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an ink exchanging method for a flexographic printing press that automatically performs ink exchanging at the time of color change accompanying an order change.
[0002]
[Prior art]
The ink replacing conventional flexographic printing machine will be described with reference to FIG. 4 (a) (b) and 5. As shown in FIG. 4 (a), an ink exchanging device of a general flexographic printing press circulates ink between one of the ink containers and a printing unit to supply the ink to the printing unit. An ink container exchange mechanism for selectively connecting a connection portion of the ink circulation supply mechanism to the ink container to one of the ink containers, and supplying a cleaning liquid to the ink circulation supply mechanism when the ink circulation supply mechanism is washed. And a cleaning liquid supply mechanism.
[0003]
FIG. 4A is a perspective view of an ink exchanging device, FIG. 4B is a side view of a printing unit including an ink roller (anilox roll and rubber roll), a printing cylinder and a receiving roll, and FIG. It is a flowchart which shows an exchange method . The printing section of the flexographic printing press has the structure shown in FIGS. That is, reference numeral 28 denotes a printing cylinder having a printing plate 29 wound around its outer peripheral surface, reference numeral 30 denotes a receiving roll disposed opposite to the printing cylinder 28, reference numeral 1 denotes an anilox roll (ink roll), reference numeral 2 denotes a rubber roll (ink roll), These constitute a printing unit.
[0004]
The flexo ink 3 is supplied from the ink container 4a (or the ink container 4b) to the nip portion P between the anilox roll 1 and the rubber roll 1 through the ink pump 7 and the ink supply pipe 8. .
The ink 3 supplied to the nip portion P is doctored by the rubber roll 2 and uniformly transferred to the outer peripheral surface of the anilox roll 1, and further, the printing plate wound around the surface of the anilox roll 1 and the outer peripheral surface of the printing cylinder 28. Due to the contact with 29, it is transferred to the printing plate 29.
[0005]
On the other hand, the corrugated cardboard sheet 31 passes between the printing cylinder 28 and the receiving roll 30 and comes into contact with the printing plate 29, thereby performing predetermined printing on the corrugated cardboard sheet 31.
During the printing operation, the ink 3a in the ink container 4a is supplied to the nip P. The surplus ink 3a overflows from both ends of the nip P, flows down to end pans (ink reservoirs) 15a and 15b, and returns to the ink container 4a through return pipes (discharge pipes) 10a and 10b. .
[0006]
Thus, the ink 3a is circulating in the ink circulation supply mechanism during the printing operation. When the predetermined printing is completed, an order change (ink color change and plate exchange) is required.
The ink circulation and supply mechanism will be described in more detail. The ink supply ports 11a and 11b are ink supply ports 5a and 5b, and the ink supply ports 5a and 5b are lids of the ink containers 4a and 4b provided with the ink supply ports 11a and 11b. Is a joint provided at the lower end of the ink supply pipe 8, and the joint 12 is detachably attached to one of the ink supply ports 11a and 11b.
[0007]
Reference numeral 13 denotes a filter provided in the middle of the ink supply pipe 8, reference numeral 7 denotes an ink pump provided in the middle of the ink supply pipe 8 above the filter 13, and reference numeral 14 denotes an ink funnel device provided at the tip of the ink supply pipe 8. The ink funnel device 14 is disposed immediately above a nip between the anilox roll 1 and the rubber roll 1.
15a and 15b are end pans disposed immediately below both ends of the anilox roll 1 and the rubber roll 1, 10a and 10b are return pipes (discharge pipes) extending from the end pans 15a and 15b, and 10 is the return pipe 10a. With a return pipe (discharge pipe) connected to 10b, the lower end of the return pipe 10 is connected to one of the return ports 6a and 6b of the ink containers 4a and 4b.
[0008]
Next, the cleaning liquid supply mechanism will be specifically described. Reference numeral 16 denotes a cleaning liquid pipe, and the cleaning water pipe 16 is connected to the ink supply pipe 8 via a solenoid valve 18 and a T-shaped joint 17.
Next, the exchange mechanism will be specifically described. 20 is a cylinder for raising and lowering a joint, 21 is a cylinder for driving a bucket, 22 is a cylinder for driving a holder, 23 is a holder, 25 is a bucket for waste liquid, 32 is a joint 12 and a return pipe. 10 is a bracket that connects the bracket 10 to the bracket 10.
[0009]
The ink exchange method at the time of order change is as follows. As shown in FIG. 4A, the joint 12 and the return pipe (discharge pipe) 10 are connected to each other by a bracket 32, and are movable in all directions, such as front and rear, left and right, and up and down. FIGS. 5A, 5B, 5C, and 5D are flowcharts at the time of ink replacement. FIGS. 5A and 5B show a state at the time of ink circulating supply (a state at the time of starting ink supply) and FIGS. ) Shows a state at the time of ink recovery, and FIG. 5C shows a state at the time of ink cleaning with a cleaning liquid.
[0010]
First, by stopping the ink pump 7, the ink circulation in the ink circulation path is stopped, and the ink is collected in the ink container 4a for a predetermined time by setting a timer as shown in FIG. 5B.
Next, in response to the recovery end signal, the bracket 32 connecting the joint 12 and the return pipe (discharge pipe) 10 is raised and retracted, and the joint 12 and the lower end of the return pipe 10 are inked as shown in FIG. It is moved to a position outside the container 4a, that is, a predetermined position on the waste liquid bucket 25, and stopped.
[0011]
In this state, the solenoid valve 18 is opened, and the cleaning liquid is automatically supplied from the cleaning liquid pipe 16 to the ink supply pipe 8 of the ink circulation supply path via the T-shaped joint 17 in the direction of the ink funnel device 14, and the ink supply pipe is opened. 8 and the inside of the ink funnel device 14, and further, the ink in the nip portion between the anilox roll 1 and the rubber roll 1, the ink in the end pans 15a and 15b, and the ink in the return pipes 10a, 10b and 10. Wash off.
[0012]
During this time, the anilox roll 1 and the rubber roll 2 are rotated at a low speed to wash out the first color ink adhering to the outer peripheral surfaces of the rolls 1 and 2, the ends of the shafts, and the inside of the end pans 15a and 15b.
At the same time, the cleaning liquid is automatically supplied from the cleaning liquid pipe 16 to the ink container 4a through the T-joint 17 in the direction of the ink container 4a, so that the inside of the ink supply pipe 8, the ink pump 7, the filter 13, and the joint 12 is removed. Wash off the ink.
[0013]
By the above operation, all the cleaning liquid is discharged from the return pipes 10a, 10b, 10 → the ink supply pipe 8 → the release port joint 12 to the waste liquid bucket 25.
The supply of the cleaning liquid is controlled by a time-adjustable timer or the like, and the solenoid valve 18 is closed and stopped by a signal after a predetermined time has elapsed. Even after the supply of the cleaning liquid is stopped, each apparatus is stopped as it is, the recovery of the cleaning liquid is performed for a certain period of time, and thereafter, the process returns to the next return step in response to the recovery work end signal from the timer. That is,
By moving the bracket 32, the joint 12 is moved to the supply port 11b of the ink container 4b in which the ink of the next new order is previously placed, and the tip of the return pipe 10 is moved to the return port 6b of the ink container 4b. Then, the movement of the bracket 32 is stopped, and then the bracket 32 is lowered, and the joint 12 is brought close to the supply port 11b as shown in FIG. The end of the return pipe 10 is connected to the return port 6b.
[0014]
In this state, the ink pump 7 is started, and the next new order of ink is circulated through the ink circulation supply path as described above, and printing is performed with the new order of ink.
[0015]
[Problems to be solved by the invention]
In the ink exchanging method using the ink exchanging device of the conventional flexographic printing press shown in FIGS. 4 and 5, when printing with the old order ink is completed, the ink pump 7 is stopped and the lower end of the ink circulation path (ink supply pipe) is stopped. 8 and the lower end of the return pipe 10) and the ink container 4a are disconnected, the circulating ink is collected in the current (old order) ink container, and then moved to the waste liquid bucket 25 by the exchange mechanism. After that, the cleaning liquid supply mechanism is operated, the ink circulation path is cleaned with the cleaning liquid, the contaminated cleaning liquid after cleaning is discharged into the waste liquid bucket 25, and then the supply of the cleaning liquid is stopped. After collecting the dirty cleaning liquid for a certain time, the lower end of the ink circulation path is connected to the next new order ink container 4b to start printing with the new order ink. That.
[0016]
That is, after the supply of the cleaning liquid is stopped, the polluted cleaning liquid is collected after waiting for the natural outflow.
For this reason, a considerable amount of time is required for collecting the liquid in the roll nip and the circulation path. However, in actuality, the next printing (supply of ink) is restarted without sufficient liquid recovery time because it is necessary to give priority to productivity. Therefore, when ink circulation is started, the roll nip and the circulation path The residual cleaning liquid remaining on the way flows back into the ink container, diluting the ink, lowering the viscosity of the ink, or mixing the residual ink of the old order and discoloring the ink of the new order, There is a problem that the print quality is deteriorated and that a new order of ink cannot be used.
[0017]
The present invention has been proposed in view of the above problems, and its object is to (1) significantly reduce the recovery time of the cleaning liquid, and (2) eliminate dilution by the cleaning liquid remaining in the ink circulation supply path. It is possible to prevent a decrease in ink viscosity (concentration), and (3) it is possible to eliminate contamination of old-order ink remaining in the ink circulation supply path, thereby preventing contamination of new-order ink, and as a result, productivity. Another object of the present invention is to provide a method of exchanging ink for a flexographic printing press, which can improve print quality.
[0018]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a process for collecting ink before washing an ink circulation supply mechanism, a connection portion between the ink circulation supply mechanism and the ink container, and the ink container of the ink circulation supply mechanism. Moving the return pipe to a position above the waste liquid recovery section, and then supplying a cleaning liquid to the ink circulation supply mechanism to wash the ink circulation supply mechanism; and cleaning the ink circulation supply mechanism from the connection section and the return pipe. After the washing liquid is collected in the waste liquid collecting part, the connecting part is moved to and connected to another ink container different from the ink container, and a direction switching valve provided in the return pipe is moved from the direction of the other ink container to the other ink container. Switching to the direction of the waste liquid collecting section, supplying new ink to the ink circulating supply mechanism, and forcibly discharging the cleaning liquid remaining inside the ink circulating mechanism to the waste liquid collecting section. It characterized the door (claim 1).
[0019]
In the ink replacement process of a flexographic printing machine of claim 1, it may also be used 3-way valve or 2-way valve in the directional control valve (claim 2).
[0020]
[Action]
The ink exchanging method for a flexographic printing press according to the present invention is configured as described above. At the time of washing, the direction switching valve is switched to the direction of the ink container, and the washing liquid is supplied to the ink circulation supply mechanism in the same manner as in the conventional ink exchanging apparatus. After cleaning the ink circulation supply mechanism and collecting the waste liquid (washing liquid after cleaning) to the waste liquid recovery section, the ink container storing the new order ink and the ink supply pipe side of the ink circulation supply mechanism Is connected and the direction switching valve is switched to the direction of the waste liquid collecting section, ink is supplied for a predetermined time, and the residual waste liquid (residual cleaning liquid) is forcibly discharged to the waste liquid collecting section together with the ink. After a predetermined time has passed in this state, or when the color of the returning liquid has reached a predetermined density, the direction switching valve is switched to the direction of the ink container, and the ink of the new order is circulated to the ink circulation supply mechanism to print the ink. Supply to the department.
[0021]
【Example】
Next, an ink exchanging method for a flexographic printing press according to the present invention will be described with reference to an embodiment shown in FIGS. FIG. 1 is a perspective view of an ink exchanging device used in the ink exchanging method, and FIG. 2 is a flowchart showing functions (operating state) of the ink exchanging device together with the ink exchanging method .
[0022]
1 and 2 are anilox rolls, 2 is a rubber roll, 3 is a flexographic ink, 4a and 4b are ink containers, 5 and 5 are lids of the ink containers 4a and 4b, and 6a and 6b are lids 5 and 5 of the same. A return port provided, 7 is an ink pump, 8 is an ink supply pipe, 10 is a return pipe (discharge pipe), 11a and 11b are the above lids, supply ports provided in 6a and 6b, 12 is a joint, 13 is a filter, 14 Is an ink funnel device, 15a and 15b are end pans, 16 is a washing liquid pipe, 17 is a T-joint, 18 is a solenoid valve, 20 is a cylinder for raising and lowering a joint, 21 is a cylinder for driving a bucket, 22 is a cylinder for driving a holder, 23 Is a holder, 25 is a waste liquid bucket (waste liquid recovery unit), 26 is a three-way valve (direction switching valve), and 27 is a waste liquid discharge pipe.
[0023]
The configuration and functions of the printing unit in the flexographic printing machine are the same as those of the conventional printing unit. Next, a method of exchanging ink in a flexographic printing machine will be specifically described. When the printing of a certain order is completed and the ink is to be replaced by an order change, the ink pump 7 is stopped and the start push button switch of the control circuit of the replacing mechanism (not shown) is pressed to perform the ink replacing operation. Start. That is, from the state of FIG. 2A, the ink pump 7 is first stopped, and the ink in the ink circulation path is collected in the ink container 4a as shown in FIG. 2B. At this time, the three-way valve 26 has been switched to the direction of the ink container 4a.
[0024]
When a predetermined time set by the timer elapses from this state, and the ink collection is completed, the ink supply pipe 8 and the joint attached to the lower end thereof as shown in FIG. 12 is raised by a joint lifting cylinder 20, the holder 23 is retracted by the holder driving cylinder 22, and the joint 12 of the ink supply pipe 8 and the lower end of the return pipe (discharge pipe) 10 are separated from each other by a waste liquid bucket (waste liquid). (Collection unit) 25.
[0025]
In this state, the solenoid valve 18 is opened, and the washing liquid is automatically supplied to the anilox roll 1 and the rubber roll 2 through the washing liquid pipe 16 → the T-joint 17, so that the inside of the ink supply pipe 8 and the ink funnel device 14 Rinse inside and out. Further, the ink in the roll nip, the ink in the end pans 15a and 15b, and the ink in the return pipes 10a and 10b and the return pipe 10 are washed away.
[0026]
At this time, the anilox roll 1 and the rubber roll 2 are spinning at a low speed and wash off the first color ink adhering to the outer peripheral surfaces of the rolls 1 and 2 and the ends of the shafts and the inside of the end pans 15a and 15b.
On the other hand, the cleaning liquid is automatically supplied in the direction of the cleaning liquid pipe 16 → the T-joint 17 → the ink container 4a to flush the ink inside the ink supply pipe 8 and the ink inside the ink pump 7, the filter 13 and the joint 12. .
[0027]
By the above operation, all the cleaning liquid is discharged from the lower end of the return pipe 10 and the joint 12 of the ink supply pipe 8.
The stop of the supply of the cleaning liquid is controlled by a timer or the like capable of adjusting the time, the solenoid valve 18 is closed by a signal obtained when a predetermined time has elapsed, the supply of the cleaning liquid is stopped, and the next step is started. That is,
After the supply of the cleaning liquid is stopped, the cleaning liquid is collected for a certain period of time. Next, the holder driving cylinder 22 is operated to transfer the joint 12 of the ink supply pipe 8 and the lower end of the return pipe 10, which are supported by the holder 23 to be able to move in the vertical direction, to the right side in FIG. Then, the joint 12 is stopped at the supply port 11b of the ink container 4b in which new ink of the next order is previously stored, and the lower end of the return pipe 10 is stopped at the return port 6b of the ink container 4b.
[0028]
When the collection of the cleaning liquid is completed, the holder 23 is advanced by the bucket driving cylinder 21 as shown in FIG. 2D, and the supply pipe side joint 12 of the ink circulation supply path is lowered by the joint elevating cylinder 20 to move the holder 23 to the next position. Is automatically brought close to the supply port 11b of the new order ink container 4b. The switching between the three-way valve (direction switching valve) 26 in the direction of the waste bucket (waste liquid recovery unit) 25. At this time, the ink supplied by the ink pump 7 is forcibly extruded and dilutes the residual waste liquid (residual cleaning liquid) in the ink circulation path for a predetermined time, and is discharged from the waste liquid discharge pipe 27 to a waste liquid bucket outside the ink container. (Waste liquid recovery unit) 25.
[0029]
The forcible discharge time is set by a timer based on experience, the color of the returning waste liquid is detected by a sensor, and this detection signal is fed back to control or is visually determined by an operator.
Then, after the elapse of the forcible discharge time, the three-way valve 26 is switched to the direction of the ink container 4b to collect the circulating ink 3b into the ink container 4b, and then the ink 3b in the ink container 4b is circulated and supplied. The ink is circulated through the mechanism, and the ink 3b is supplied to the printing unit.
[0030]
In this way, the residual waste liquid (residual cleaning liquid) is forcibly discharged with a new order of ink, so that the ink replacement time is greatly reduced. Further, the diluted ink is not returned to the ink container to prevent the ink viscosity from decreasing.
Although the three-way valve 26 is used in the above embodiment, the direction switching valve is not limited to the three-way valve, but may be a two-way valve 33 shown in FIG.
[0031]
That is, FIG. 3A corresponds to the state of FIG. 2D, in which a two-way valve 33 is provided below the discharge pipe 10. FIG. 3B shows a printing unit in which ink or water returning from the discharge pipe 10 is temporarily stored in the ink reservoir 35 and then sucked up by the discharge pump 34. A direction valve 33 is provided. In this example, the discharge pump 34 is stopped and the two-way valve 33 is opened to prevent the residual waste liquid (residual cleaning liquid) from being mixed into the new order ink can 4b. In view of these points, the two-way valve 33 may be used.
[0032]
【The invention's effect】
As described above, the ink exchanging method of the flexographic printing press according to the present invention switches the direction switching valve to the direction of the ink container at the time of washing, and supplies the washing liquid to the ink circulation / supply mechanism as in the conventional ink exchanging method. After cleaning the circulating supply mechanism and collecting the waste liquid (washing liquid after cleaning) to the waste liquid recovery section, connect the ink container storing the new order ink to the ink supply pipe side of the ink circulating supply mechanism and set the direction. The switching valve is switched to the direction of the waste liquid collecting section, ink is supplied for a predetermined time, and the residual waste liquid (residual cleaning liquid) is forcibly discharged to the waste liquid collecting section together with the ink. After a predetermined time has passed in this state, or when the color of the returning liquid has reached a predetermined density, the direction switching valve is switched to the direction of the ink container, and the ink of the new order is circulated to the ink circulation supply mechanism to print the ink. (1) The recovery time of the cleaning liquid can be greatly reduced, (2) The dilution by the residual waste liquid (residual cleaning liquid) remaining in the ink circulation supply path can be eliminated, and the ink viscosity (concentration) can be reduced. (3) Mixing of old order ink remaining in the ink circulation supply path can be eliminated, and contamination of new order ink can be prevented, and as a result, productivity and print quality can be improved.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an embodiment of an ink exchanging device of a flexographic printing press according to the present invention.
2A is a flowchart showing a state at the time of ink circulation supply, FIG. 2B is a flowchart showing a state at the time of ink recovery, FIG. 2C is a flowchart showing a state at the time of ink cleaning with a cleaning liquid, and FIG. It is.
FIG. 3A is a side view showing a case where a two-way valve is provided in the middle of a return pipe, and FIG. 3B is a side view showing a case where a two-way valve is provided in an ink reservoir.
FIG. 4A is a perspective view illustrating a conventional ink exchanging device of a flexographic printing press, and FIG. 4B is a side view illustrating a printing unit.
5A is a flowchart showing a state at the time of ink circulation and supply, FIG. 5B is a flowchart showing a state at the time of ink recovery, FIG. 5C is a state at the time of ink cleaning with a cleaning liquid, and FIG. It is.
[Explanation of symbols]
1 Anilox roll (ink roller)
2 Rubber roll (ink roller)
3a, 3b Flexo ink 4a, 4b Ink container 5, 5 Lid 6a, 6b Return port 7 Ink pump 8 Ink supply pipe 10 Return pipe (discharge pipe)
10a 〃
10b 〃
DESCRIPTION OF SYMBOLS 11 Supply port 12 Joint 13 Filter 14 Ink funnel device 15 End pan 16 Cleaning liquid pipe 17 T-joint 18 Solenoid valve 20 Joint up / down cylinder 21 Bucket driving cylinder 22 Holder driving cylinder 23 Holder 25 Waste liquid bucket (waste liquid collection part)
26 Three-way valve (directional switching valve)
27 Waste liquid discharge pipe

Claims (2)

A step of collecting ink before washing the ink circulation supply mechanism;
After moving the connection part between the ink circulation supply mechanism and the ink container and the return pipe of the ink circulation supply mechanism to the ink container above the waste liquid collecting part, the cleaning liquid is supplied to the ink circulation supply mechanism. Washing the ink circulation supply mechanism;
After recovering the cleaning liquid after cleaning from the connection portion and the return pipe to the waste liquid recovery section, the connection section is moved to and connected to another ink container different from the ink container, and provided in the return pipe. The direction switching valve is switched from the direction of the other ink container to the direction of the waste liquid collecting section, and new ink is supplied to the ink circulating supply mechanism to force the cleaning liquid remaining in the ink circulating mechanism to the waste liquid collecting section. And a step of discharging ink to a flexographic printing press. 2. The method according to claim 1, wherein a three-way valve or a two-way valve is used as the direction switching valve .

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