JPS60248354A - Intermittent feeder of continuous sheet - Google Patents

Abstract

PURPOSE:To decrease the length of contact with a printing surface side of a sheet by pull members within a repeated feeding length and to reduce restricted areas of printing by pulling the opposite side of a printing surface of the sheet with a suction roll. CONSTITUTION:A sheet 3 is wound around a suction roll 15, and pull members 17 and 18 are unstalled on a pull roll 16 to pull the sheet 3. The installation positions for the pull members 17 and 18 are provided to be adjustable in the direction of rotation, and an outside diameter D is made to be equal to the outside diameter D of a printing plat 14, and an arc length L2 (printing length) is made less than the outer peripheral length L1 of the pull members 17 and 18, and the peripheral surface speeds of both are adjusted to coincide with each other, and the peripheral surface speed of rotation of the suction roll 15 and the peripheral speeds of rotation of the pull members 17 and 18 and the printing plate 14 are also made to be in accord with others.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention can be applied to flexographic rotary presses, planographic rotary presses, rotary die cutters, flat plate punching machines, etc. The present invention relates to an intermittent feeding device for a continuous sheet for sequentially printing a predetermined size on each scheduled printing section of a web or other continuous sheet with an arbitrary printing length within the range of .

(Prior Art) FIG. 12 shows a typical continuous sheet (hereinafter referred to as sheet) rotary printing press. Now, the roll-shaped sheet 1 is axially suspended at the center by the unwinding machine 2, and is held and pulled by the pull rolls II, so that it is rotated in the direction of the arrow, rewound, and advances toward the printing section 1o. The rewound sheet 3 passes through the winding roll 4 between the printing cylinder 5 and the impression cylinder 6 of the printing section 10 and is printed. In this example, three sets of printing units 1o are shown, but generally, depending on the number of colors to be printed, three to six sets of printing units 1o are used.
There is a printed section for each color. The printed sheet 3 is pinched and pulled by a pair of pull rolls 11, and further wound up again into a roll 12 by a winder 13.

Furthermore, the printing mechanism shown in FIG. 13 transfers the ink 34 in the ink reservoir 8 onto the surface of the printing plate 14 attached to the plate cylinder 5 by the roll 7, and further prints on the surface of the sheet 3. Ru. Excess ink (more than the necessary amount of ink) on the surface of the ink applicator roll 7 is scraped off by the doctor blade 9 and flows back into the ink reservoir. Note that the outer peripheral surface speeds of the pull roll 11, the impression cylinder 6, and the printing plate 14 are matched so that the traveling speed of the sheet 30 matches the surface peripheral speed of the printing plate.

Furthermore, the sheet 3 is unwound more than necessary due to the inertia of the roll 1 in the unwinding machine 2, so that the sheet does not become sagging.
A brake device (not shown) is attached to the roll l. The winder 13 is also equipped with a drive device (not shown) for the roll 12 for winding up the sheet 3 sent from the pull roll 11. The printing length on a sheet in such a rotary printing press is determined by the circumferential length of the printing plate 14, and this maximum length is less than or equal to the circumferential length πD of the outer diameter of the printing plate.

Now, the repeat printing length is determined by the arc length of the printing plate 14, but if this length is smaller than the outer circumferential length πD, a blank area will be left where no printing is done. This blank space is completely unnecessary and will be cut and discarded in the next process after printing and winding. Therefore, in the conventional machine, the following proposals have been made in order to reduce this blank area.

(1) A method of changing the outer diameter dimension (D, ) of the plate cylinder 5 according to the printing length, that is, a method of replacing the plate cylinder 5.

(1) A method of raising or lowering either the upper or lower part of the pull roll, which is rotating at a constant speed, according to the printing length, as shown in Figure 14. In the example shown in Figure 14, while the lower pull roll is rising, The sheet is clamped and pulled, and the sheet stops while it is being lowered.Also, since printing is performed only while the sheet is running, this intermittent sheet feeding method changes the raising and lowering timing of the pull roll depending on the desired printing length.

(III) Attach the tension member 35 of the sheet 3 to one side of the pull roll 11 shown in FIG. An intermittent feeding method for sheets with an arc length dimension of 14 or more.

The above measures (1), (It), and (III) have been proposed in the past, but each of them had the following drawbacks.

Disadvantages of (1). Method (1) is the most commonly used method, but the work of replacing the plate cylinder every time the printing length changes is complicated, the printing mechanism is complicated, and the biggest drawback is that A desired number of expensive plate cylinders with different circumferential dimensions must be prepared, and the manufacturing cost of the printing sheet increases.

(IT) disadvantages. This method (II) is an improvement measure to compensate for the drawback of (1) (there is no need to replace the plate cylinder).

However, since the sheet is held and pulled, pressure is applied to the printing surface of the sheet printed in the previous process, which may remove ink that has not completely dried and adhered to the sheet surface, or print with ink on the surface of the pull roll. The surface may become dirty, and it is mechanically difficult to frequently move the rolls with high inertia up and down, which causes mechanical vibrations and has the disadvantage of not being able to keep up with high-speed operation.

Disadvantages of (III). Method (ill) is also an improvement measure to compensate for the drawback of (1) (there is no need to replace the plate cylinder).

However, as in (n), the sheet is held and pulled, and in this respect it has the same drawbacks as (II). In addition, the tension member must be replaced every time the printing length changes, and it is necessary to prepare as many tension members with different arc length dimensions as desired.
) had similar drawbacks.

Furthermore, when this tensile member is made of plastic or rubber, durability, mainly wear, is a problem (a decrease in sheet tensile force and tensile dimension due to wear, especially when a stationary sheet is instantly accelerated). (The change in the amount of slip during the process is directly linked to the change in the repetition length of the sheet). In addition, when manufacturing from metal, there are problems that need to be solved in actualization, such as high manufacturing costs due to the high precision required.

(Problems to be Solved by the Invention) The present invention has been proposed in order to eliminate the above-mentioned conventional drawbacks, and an object of the present invention is to obtain a high-speed, high-precision continuous sheet intermittent feeding device.

(Means for Solving the Problems) In order to achieve this object, the present invention has a system in which a continuous sheet is wound around the suction roll and runs between a rotating suction roll and a tension roll. Intermittent feeding is possible by switching the range of action of the suction force, and the tension roll is provided with a tension member that clamps the sheet together with the suction roll and is divided into front and rear parts whose position can be freely adjusted in the circumferential direction. This allows for intermittent feeding and stopping of continuous sheets.

(Function) Now, the suction roll pulls the non-printing surface side to minimize printing stains, and the sheet is intermittently fed by increasing and decreasing the suction pressure, and one of the tension members pulls the sheet while the suction pressure rises when the sheet is accelerated. , the other pulls the sheet while the suction pressure returns to atmospheric pressure.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings. Fig. 1 shows the configuration of a sheet rotary printing mechanism showing an embodiment of the present invention, and Figs. 2 to 5 show a pull roll section for intermittent feeding. shows. In the figure, a rolled sheet 1, an unwinding device 2,
Winding roll 4, printing unit 10 (printing cylinder 5, impression cylinder 6, ink depositing roll 7, ink reservoir 8, doctor blade 9, printing plate 14, ink 34), roll 12, winding machine 1
The configuration of No. 3 is the same as the conventional one.

Now, in Fig. 1, the conventional rewinding machine 2 and printing section 1 shown in Fig. 12 are shown.
A suction box 20 is installed between 0 and 3 to adsorb the advancing sheet 3 and perform a braking action by friction. Furthermore, a sheet feed roll 19 is provided between the pull roll section 21 and the winder 13.

2 to 5 show details of the pull roll section 21, in which the sheet 3 is wound around a suction roll 15 that is hollow inside and has a large number of suction holes, and a pull roll 16 is provided below to pull the sheet 3. Attached to the roll 16 are tension members 17 and 18 of the sheet 3. Tension member 17
．． The mounting position of the printing plate 18 is adjustable in the rotational direction, and the outer circumference coincides with the outer circumference of the printing plate 14 shown in FIG. is less than the outer circumferential dimension L of the tension member 17, 18 (FIG. 2 (b)), and furthermore, the surface circumferential speeds of both are also the same (that is, the same number of rotations). Further, the rotational peripheral speed of the surface of the suction roll 15 and the rotational peripheral speed of the tension member 17, 18 and the printing plate 14 are also the same.

Next, referring to FIG. 3, the suction roll 15
Both the pull rolls 16 and 16 are rotatably supported by bearings 36, and each roll is connected via a gear 22, 30 so that both rolls rotate at the same speed. The tension roll 16 is driven by another drive means (not shown). Furthermore, a suction partition member 33 is built into the suction roll 15L7) to prevent unnecessary suction. The suction range by the suction partition member 33 is shown by hunting in FIGS. 2(a) and 3.

The suction partition member 33 is connected to the suction duct 23 via a joint 37, and the suction duct 23 is further connected to the suction chamber 25.

Air is sucked into the suction chamber 25 by the suction blower 24 which is constantly operating, and the pressure is below atmospheric pressure.

On the other hand, at one shaft end of the tension roll 16, the tension roll 1
A plurality of cams 28 are attached to rotate in synchronization with 6, and the positions of these cams can be adjusted in the rotational direction. Also, the cam follower 29 in contact with this cam 28 is connected to the piston shaft 31.
This piston shaft 31 is attached to the end of the spring 3
A downward force is always applied to the cam 2 by the cam 2.
The operation of raising by 8 and lowering by spring 32 is repeated every rotation of the tension roll 16.

The piston shaft 31 has a suction valve 26 and an atmosphere release valve 2.
7 is attached and the piston 31 is pushed up by the cam 28 via the cam follower 29 (FIG. 5), the suction chamber 25 and the suction duct 2 are closed by the suction valve 26.
3, the atmosphere release valve 27 is opened and the atmosphere flows in, and the air pressure inside the Sushijin roll 15 becomes atmospheric pressure, and the tensile force of the sheet 3 by the Sushijin roll 15 decreases (the suction box 20 described above (The brake force applied to seat 3 will be less than that due to the above).

Conversely, when the piston 31 is pushed down by the spring 32 as shown in FIGS. 3 and 4, the suction valve 26
is opened, the atmosphere release valve 27 is shielded, the pressure inside the suction roll 15 becomes less than atmospheric pressure, the sheet 3 is brought into close contact with the suction roll 15, and the suction box 20 is closed.
The seat 3 is pulled by overcoming the braking force.

Next, to explain the operation of the embodiment configured as above, the continuous sheet 3 is
It is intermittently pulled by an amount equivalent to the outer circumferential dimension L1 of 7.18. When the tensile force of the sheet 3 in the pull roll section 21 is removed, the sheet 3 is stopped instantaneously by the suction force of the suction box 20.

Further, the sheet 3 that is intermittently fed from the pull roll section 21 is constantly fed toward the winding machine 13 by the sheet feeding roll 19.

As shown in FIG. .+) [As shown by the broken line in FIG. 1 between the pull roll section 21 and the feed roll 19, there is slack ( (This is faster than the sheet tensioning speed of the feed roll), so after it stops, it becomes stretched as shown by the solid line.

Such behavior is repeated every rotation of the tension roll 16].

In synchronization with the behavior of the sheet 3, printing plates 14 are applied to each plate cylinder 5 so that printing is performed while the sheet 3 is traveling.
is installed.

In addition, in the case of three-color printing (having three sets of printing units 10) as in this specific example, in order to match the printing points, the printing point A for the first color, the printing point B for the second color, and the printing point B for the second color shown in FIG. 3
The position of the winding roll 4a is adjusted as shown by the broken line in FIG. 1 so that the length of each sheet between the printing points C of the color matches the amount of sheet advance (outer circumferential dimension L) for each cycle. .

In this way, the sheet 3 is intermittently fed by the pull roll unit 21, printing is performed only while the sheet is in progress, and the printable length is driven so that the respective relative printing positions coincide within the repeatable feeding length (external circumferential dimension L). , controlled.

Next, the function of the pull roll section 21 for intermittently feeding the sheet will be described. First, as shown in FIG. 7, the front tension member 1
When the sheet 3 is held between the suction roll 15 and the tip of the sheet 3, the sheet 3 starts to advance. At the same time, the inside of the suction roll 15 is sucked so that the pressure becomes below atmospheric pressure,
As shown in FIG. 8, the tension member 17 and the suction roll 15
The sheet is pulled by both adsorption forces (in the range of time Δt1 shown in FIG. 6).

Next, the rotation of the pull roll 1G progresses, and in the state shown in FIG. 9, the sheet is pulled only by the suction force of the suction roll 15, and in the state shown in FIG. 10, that is, the rear tension member 18
At the same time, the suction roll 15
The pressure increases so that the inside is released to atmospheric pressure [The suction force of the suction roll gradually decreases, so the sheet 3 is pulled by the tension member 18 on the rear side until the suction force is completely lost (as shown in Figure 6). within the range of time Δt2)]. Finally the first
In the state shown in Figure 1, the tensile force on the sheet 3 is released and it stops (
At this time, the suction roll 15 is completely restored to atmospheric pressure, and the suction force of the sheet is gone).

In addition, when changing the sheet feed length (outer circumferential dimension L), it is possible to change the attachment position of the rear tension member 18 and at the same time change the timing of opening the suction roll 15 to the atmosphere. Below are the front and rear tension members 17.18
The relationship between the speed change of the sheet 3 and the pressure inside the suction roll 15 will be explained in more detail with reference to FIG.

The upper part of FIG. 6 shows the change in speed of the sheet, and the lower part shows the change in pressure within the printing roll.

Now, when the sheet 3 is held between the front tension member 17, the sheet speed instantly becomes {circle around (rotational speed of the suction roll and tension member surface adjusted in advance)}. At the same time, the air inside the suction roll 15 is sucked, and the pressure gradually decreases. While this pressure decreases to a preset pressure, that is, during the period of Δ1+, the sheet 3 is reliably held by the tension member 17 on the front side. Here, the arc length of the front tension member 17 is 1. must be greater than or equal to Δt1×V.

Next, at the same time as the sheet 3 is held between the tips of the rear tension members 18, the suction inside the suction roll 15 is released and the pressure is gradually restored to atmospheric pressure. During this time, that is, Δt2,
The sheet 3 is surely held between the tension members 18 on the rear side. Similarly, the arc length 12 of the rear tension member 18 is △tl X V
It is necessary to do more than that.

As is clear from the above, in order to reliably obtain a constant feed length (outer circumferential dimension L) (because the running and stopping timing of the sheet 3 is not stable only with the action of the suction roll 15), the front and rear tension members 17, 18 plays an important role. The pressure switching within the suction roll 15 is effected by operating the valves 26 and 27 by the cam 28 which rotates synchronously with the tension roll 16, as described above. Further, the cams 28 are made up of a plurality of combinations, and by changing the mounting position of the cam 28 in the rotational direction as shown in FIG. It is possible.

(Effects of the Invention) The present invention is configured as described above in detail, and by pulling the non-printing surface side of the sheet with a suction roll, the length of contact with the printing surface side by the tension member within the repeated feeding length is increased. This reduces the printing restriction range due to contact. Further, there is little change in feed length due to wear of the tension member.

When pulling the sheet using only the tension member as in the past,
The rate of change in feed length due to wear is large.

Furthermore, there is no need to replace the tension member each time the feed length is changed, and only the mounting position needs to be changed, reducing preparation time and eliminating the need to prepare a large number of tension members depending on the feed length. The manufacturing cost of printed sheets can be reduced.

Therefore, the tension member can be manufactured in advance as a mechanical component by a machine maker with high precision and high durability. As in the past, it is almost impossible to supply tensile members that match the production content (multiple feed lengths) of the machine user, and even if it were possible, it would be very expensive, which has the disadvantage of increasing the manufacturing cost of printed sheets. However, according to the present invention, such drawbacks are not present at all.

[Brief explanation of the drawing]

Figure 1 is a side sectional view of a continuous sheet rotary printing machine showing an embodiment of the present invention, Figure 2 (a) is a detailed view of the main parts in Figure 1, and Figure 2 (b) is the outer periphery of the tension roll. An explanatory diagram showing the dimension L1, FIG. 2(c) is an explanatory diagram showing the arc length dimension of the printing plate in FIG. 1, FIG. 3 is a front sectional view showing details of the pull roll part in FIG. 1, and FIG. 4 and Fig. 5 are side sectional views of the main parts in Fig. 3 in different operating states, Fig. 6 is an explanatory diagram showing changes in sheet speed and suction pressure of the pull roll, Figs. 7 and 8, Figures 9, 10 and 1
Figure 1 is a side view of the pull roll section in different operating states, Figure 12 is a side sectional view showing a conventional continuous sheet rotary printing press, and Figure 13 is a detailed view of the printing unit in Figure 12. FIGS. 14 and 15 are side views showing different examples of conventional pull roll sections, respectively. Description of main parts of the figure 3 - Sheet 10 - Printing section 15 - Suction roll 16 - Tension roll 17. 18 - Tension member 21 - Pull roll section 22. 30 - Gear 33 - Suction partition member Patent applicant Mitsubishi Heavy Industries, Ltd.

Claims (1)

[Claims] A continuous sheet is wound around the same suction roll and runs between the rotating suction roll and tension roll.
The suction roll enables intermittent feeding by switching the range of action of the suction force, and the tension roll is provided with a tension member which is divided into front and rear sections and whose position can be freely adjusted in the circumferential direction to sandwich the sheet together with the suction roll. An intermittent feeding device for continuous sheets, which is characterized in that it is possible to intermittent feed the continuous sheet by running and stopping the continuous sheet.