JPH0688409B2 - Ink discharge method and device for printing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention rapidly performs ink exchange accompanying order change in a printing machine that forms an ink reservoir above a contact portion between an anilox roll and a doctor roll. The present invention relates to an ink discharge method for a printing machine and a device therefor.

[Conventional technology]

Generally, in a printing machine that prints on thick paper materials such as corrugated cardboard sheets, the anilox roll and the doctor roll are brought into relative contact with each other, an ink reservoir is formed above the contact portion, and the amount of ink in the ink reservoir is preset. The anilox roll and the doctor roll are rotated while maintaining the set amount, and a certain amount of ink is transferred from the anilox roll to the printing cylinder and transferred to the paper material from the printing cylinder.

And when changing the print color by order change, conventionally, after the ink in the ink reservoir was allowed to flow out naturally, the anilox roll and doctor roll, as well as each part of the ink flow path system, were washed, and then another ink was added. It was supplied in the ink fountain.

However, when the ink is naturally discharged from the ink reservoir by changing the order and discharged in this way, it is difficult to flow because the anilox roll and the doctor roll are horizontally installed, and it takes a lot of time to discharge the ink. When the order change is performed ten times, the ratio of the time required for discharging the ink from the ink reservoir and the time required for washing increases with respect to the total operating time, which causes a decrease in operating efficiency.

Moreover, in the method of discharging the ink by natural outflow, although the water is discharged to a certain level, it becomes difficult to discharge the residual liquid after that. Therefore, the amount of ink that can be collected is small, and the amount of ink that can be collected is small, as well as the ink that remains in the ink reservoir, after the ink amount in the ink reservoir has naturally discharged to some extent. There are many.

In recent years, in order to eliminate the above-mentioned drawbacks, an invention using air pressure as described in JP-B-55-45390 and an invention using a blade proposed by the present applicant have been proposed.

In the invention utilizing the air pressure, the jet nozzle is made to face above the ink reservoir, and the ink in the ink reservoir is discharged from the side of the ink reservoir by the air pressure from the jet nozzle.

[Problems to be Solved by the Invention]

However, the above ink discharging method does not always set the ink amount in the ink reservoir to a constant amount, and may increase or decrease depending on the printing condition. Also, the ink discharging operation may be performed once by the air pressure. Not only do
The ink may be discharged several times. In this case, the amount of ink decreases each time the discharging operation is performed, so depending on the amount of ink, the pressure of the air is too high, the ink in the ink reservoir scatters, and the pressure of the air is too low, There was a problem that ink was not discharged from the ink reservoir.

On the other hand, in the ink discharging method using a blade, the blade is moved from one side in the ink reservoir toward the other side, thereby discharging the ink in the ink reservoir.

However, this method easily scratches the surface of the anilox roll or doctor roll with the blade,
As a result, a blade with high processing accuracy is required.

In addition, each of the ink discharging methods requires auxiliary equipment and requires a dedicated control device for the ink discharging method, resulting in a large size of the entire apparatus and a high price.

Therefore, in view of the above circumstances, the present invention can discharge ink from the ink reservoir in a short time and well, without using any auxiliary equipment and not requiring a dedicated control device. It is an object to provide an ink discharging method for a printing machine.

[Means to be Solved by the Invention]

In order to achieve the above-mentioned object, (1) an ink reservoir is formed above a contact portion between an anilox roll and a doctor roll which are in contact with each other, and the ink reservoir is rotated from above both rolls toward the contact portion. In a printing machine that transfers ink from the anilox roll to the printing cylinder, the anilox roll and the doctor roll are rotated from below the both rolls toward the contact part, and the ink in the ink reservoir is dripped and discharged to the lower tray. Ink discharge method for printing machines.

(2) The anilox roll and the doctor roll, which are arranged in contact with each other, are linked to a drive mechanism capable of rotating in the forward and reverse directions, an ink supply nozzle is arranged above the contact portion, and an ink tray is arranged below the contact portion. It is an ink discharge device of a printing machine, characterized in that an anilox roll and a doctor roll which are in contact with each other are always rotated in reverse.

[Action]

In the embodiment, when the color to be printed is changed by changing the order, the ink recovery process is first performed.

That is, as shown in FIG. 3, the anilox roll 1 and the doctor roll 2 are rotated in the outward (arrow B) direction, which is the reverse of the printing.

By this rotation, the ink in the ink reservoir 5 adheres to the surface of the anilox roll 1 and the doctor roll 2 without being scattered due to the viscosity characteristic of the ink, and the anilox roll 1 and the doctor roll 2 on which the ink is placed.
Although it tries to enter upward from the lower part 17 of the contact part, it is squeezed at the contact part of the anilox roll 1 and the doctor roll 2 and drips onto the receiving pan 9 below. The ink on the tray 9 is collected in the ink tank 13 via the collecting pipe 12.

After the ink is collected from the ink reservoir 5, the washing process is started.

〔Example〕

Hereinafter, an embodiment of an ink discharging method for a printing press and an apparatus therefor according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a front view of a printing machine provided with an ink discharge device. In the figure, 1 is an anilox roll, 2 is a doctor roll, and 3 is a printing cylinder.

Of course, the anilox roll 1, the doctor roll 2 and the printing cylinder 3 are rotatably supported between the left and right frames 4, 4.

A press roll (not shown) for holding the corrugated cardboard sheet between the frames 4 and 4 is also rotatably supported between the frame 4 and the upper printing cylinder 3.

An ink reservoir 5 is provided above the contact portion where the anilox roll 1 and the doctor roll 2 are in contact with each other, as shown in FIG.

A nozzle 6 for ink supply and water supply is arranged above the center of the ink reservoir 5. Ink reservoir 5 above
Recovery ducts 7 and 8 are disposed below both ends of the, and a receiving tray 9 is disposed below the anilox roll 1 and the doctor roll 2 along the axial direction.

The collection ducts 7, 8 and the tray 9 are collection pipes 10, 11, 12
Is communicated with the ink tank 13 via. The ink in the ink tank 13 is piped so as to be injected from the nozzle 6 into the ink reservoir 5 by the pump 14.

Further, nozzles 15 and 16 are arranged above the recovery ducts 7 and 8, and the nozzles 15 and 16 are provided from a water supply source through a valve device.
Water is jetted from the nozzles 15 and 16 by being piped to 6.

Water is also jetted from the water supply source through the valve device from the nozzle 6.

During normal printing, the anilox roll 1, the doctor roll 2 and the printing cylinder 3 equipped with the printing plate rotate in the direction shown by the arrow A in FIG. Is transferred from the anilox roll 1 to the printing cylinder 3 by a predetermined amount by the doctor roll 2, and is transferred from the printing cylinder 3 to the corrugated board sheet S.

At this time, the peripheral speed of the doctor roll 2 is set to the printing cylinder 3
In order to appropriately adjust the amount of ink transferred to, the peripheral speed of the anilox roll 1 can be freely changed.

That is, an amount of ink corresponding to the difference between the peripheral speed of the anilox roll 1 and the peripheral speed of the doctor roll 2 is transferred from the anilox roll 1 to the printing cylinder 3.

On the other hand, since both ends of the ink fountain 5 are open, the ink in the ink fountain 5 is collected in the ducts 7, 8
Flow out to the ink tank 13 through the recovery pipes 10 and 11, but in order to keep the ink amount in the ink reservoir 5 at a value preset by the sensor, the ink is pumped from the ink tank 13 by the pump 14 and the nozzle. It is poured from 6 into the ink reservoir 5.

Next, when the color to be printed is changed by changing the order, the ink is exchanged through the ink recovery process and the washing process.

First, in the ink recovery process, as shown in FIG. 3, the anilox roll 1 and the doctor roll 2 are rotated in the direction of arrow B.

By this rotation, the ink in the ink reservoir 5 adheres to the surfaces of the anilox roll 1 and the doctor roll 2 without being scattered due to the viscosity characteristic of the ink, and is so-called riding on the anilox roll 1 and the doctor roll 2 in contact with each other. Although it tries to enter from the lower part 17 to the upper part, it is squeezed at the contact part of the anilox roll 1 and the doctor roll 2 and drips onto the saucer 9 below.

The ink on the tray 9 is transferred to the ink tank 13 via the recovery pipe 12.
Will be collected. After the ink is collected from the ink reservoir 5, the washing process is started. In the washing process, water is jetted from the water supply source through the valve device as well as the nozzles 15 and 16, as well as the nozzle 6.

At this time, anilox roll 1 and doctor roll 2
Needless to say, it remains rotated in the direction of arrow B shown in FIG.

Therefore, the water injected into the ink reservoir 5 adheres to the peripheral surfaces of the anilox roll 1 and the doctor roll 2 and is washed and squeezed in the contact portion in the same manner as described above to be dropped on the receiving tray 9, and then the recovery pipe. It is discharged to the outside via 12.

The water sprayed from the nozzles 15 and 16 is discharged to the outside through the recovery pipes 10 and 11 after cleaning the recovery ducts 7 and 8.

In the ink recovery process and the cleaning process, the printing cylinder 3 is preferably rotated in the direction of arrow B shown in FIG. 3, but it may be stopped.

Then, another ink is stored in the ink tank 13 and is pumped up by the pump 14 to be injected into the ink reservoir 5 from the nozzle 6 for the next printing.

By the way, as shown by a chain double-dashed line in FIG. 3, a blade 18 that moves from one end of the receiving tray 9 toward the other end to perform a scraping operation can be arranged in the receiving tray 9.

The moving mechanism of the blade 18 is such that a screw rod 19 is provided above the tray 9 along the longitudinal direction thereof,
A nut member 20 is fixed to the blade 18, and the nut member 20 is screwed onto the screw rod 19 so that the screw rod 19 is rotated by a motor. Collection pipe
12 may be connected to one end of the tray 9.

During the ink recovery process and the cleaning process, the blade
18 is moved from one end of the receiving tray 9 toward the other end, whereby the blade 18 scrapes out the ink and the washing water in the receiving tray 9 to the recovery pipe 12. In this way, the ink recovery process and the cleaning process can be performed in a shorter time.

Further, without using the blade 18, the tray 9 can be inclined steeply so as to speed up the spontaneous outflow to the recovery pipe 12.

In the ink recovery process and the cleaning process, the peripheral speeds of the anilox roll 1 and the doctor roll 2 are
The operation is performed at a lower speed than in normal printing, but the operation is not limited to this.

In addition, in the above ink recovery process and cleaning process,
It is also possible to operate while controlling the peripheral speeds of the anilox roll 1 and the doctor roll 2 so as to correspond to the properties of the ink or the like so that the ink can be effectively discharged from the ink reservoir 5 without being scattered.

〔The invention's effect〕

As described above, according to the ink discharge method for the printing press and the apparatus therefor according to the present invention, at the time of discharging the ink, the anilox roll and the doctor roll are directed outward from the ink reservoir opposite to that at the time of printing. Since the ink is rotated and discharged, no additional equipment is required, and the control device that reverses the rotation of the anilox roll and the doctor roll can also use the device that controls the operation at the time of printing. Simply rotate the anilox roll and the doctor roll in the opposite direction to when printing,
It is convenient because the ink in the ink reservoir can be forcibly discharged in a short time.

[Brief description of drawings]

FIG. 1 is a front view showing an ink discharge device of a printing machine according to the present invention, and FIG. 2 is an explanatory view showing a rotation direction of an anilox roll and a doctor roll and a state of an ink reservoir during printing, and FIG. FIG. 4 is an explanatory diagram showing a rotation direction of an anilox roll and a doctor roll when ejecting ink, and an ink ejecting state. 1 ... Anilox roll, 2 ... Doctor roll, 3 ... Printing cylinder, 4 ... Frame, 5 ... Ink reservoir, 6,15,16 ... Nozzle, 7,8 ... Recovery duct, 9 ... Saucepan, 10-12 ... Recovery tube, 13 ... Ink tank, 14 ... Pump, 17 ... Lower contact area, S ... Corrugated cardboard sheet

Claims (2)

[Claims] 1. An ink reservoir is formed above a contact portion between an anilox roll and a doctor roll which are in relative contact with each other, and the ink is transferred from the anilox roll to a printing cylinder by rotating from above both rolls toward the contact portion. In the printing press, an anilox roll and a doctor roll are rotated from below the both rolls toward the contact part, and the ink in the ink reservoir is dripped and discharged to the lower tray. 2. An anilox roll and a doctor roll, which are arranged in contact with each other, are linked to a drive mechanism capable of rotating in the forward and reverse directions, an ink supply nozzle is arranged above the contact portion, and an ink tray is arranged below the contact portion. However, the ink discharge device of the printing press is characterized in that the anilox roll and the doctor roll which are in contact with each other are always rotated in reverse.