JPH0596712A - Intermittent feeder for continuous sheet - Google Patents

Abstract

PURPOSE:To provide an intermittent continuous sheet feeder in which replacement of plate cylinder is not required at the time of modification of print length and in which impact and abrasion are suppressed. CONSTITUTION:The intermittent continuous sheet feeder comprises a drum 26 for entraining and guiding a continuous sheet, a drag roll 27 having a roll surface mounting a pair of tension members 22, 24 contacting with a sheet 3 on the drum 26, and a roll 15 and a holding roll 16 contacting detachably with the sheet 3 on the drag roll 27, wherein acceleration/deceleration of the sheet 3 is carried out by means of the drag roll 27 through the tension members 22, 24, constant speed feeding of the sheet 3 is carried out by means of the feed roll 15, and sheet tension holding at the time of stopping the sheet is carried out by means of the holding roll 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a flexographic rotary printing machine,
The present invention relates to an intermittent feeding device for a continuous sheet in a rotary cutter or the like.

[0002]

2. Description of the Related Art FIG. 5 shows a general continuous sheet (hereinafter referred to as sheet) rotary printing machine. The roll-shaped sheet 1 is centered on a rewinding machine 2 and is sandwiched and pulled by a pull roll 11. Therefore, the roll-shaped sheet 1 is rotated in the direction of the arrow to be rewound and the printing unit 1
Proceed in the direction of 0. The rewound sheet 3 is printed by the printing unit 10.
Printing is performed by passing between the plate cylinder 5 and the impression cylinder 6.

Although three sets of printing units 10 are shown in this example, generally, there are printing units for three to six colors depending on the number of colors to be printed. The printed sheet 3 is nipped and pulled by a pair of pull rolls 11, and is further wound into a roll 12 by a winder 13. In the printing mechanism shown in FIG. 6, the ink is transferred to the surface of the printing plate 14 attached to the plate cylinder 5 by the ink 21 in the ink reservoir 8 and the inking roll 7, and the surface of the sheet 3 is printed. It Excess ink (more than the required amount of ink) on the surface of the inking roll 7 is scraped off by the doctor blade 9 and flows back into the ink reservoir. The traveling speed of the sheet 3 is the same as the surface speed of the printing plate, and the outer peripheral surface speeds of the impression roller 6 of the pull roll 11 and the printing plate 14 are the same.

Further, the rewinding machine 2 is equipped with a braking device (not shown) for the rolls so that the sheets 3 are unwound more than necessary due to the inertia of the rolls and the sheets do not sag. Further, the winder 13 is provided with a drive device (not shown) for the roll 12 for winding the sheet 3 fed 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 not more than the circumferential length πD of the printing plate outer diameter D.

The repetitive printing length is determined by the arc length of the printing plate 14, but if this length is smaller than the outer peripheral length πD, a blank portion that is not printed occurs. This blank portion is completely unnecessary and is cut and discarded in the next step after winding the print. Therefore, conventionally, the following proposals have been made in order to reduce the blank area. (1) A method of changing the outer diameter dimension D ₁ of the plate cylinder 5 according to the printing length. That is, the plate cylinder 5 is replaced according to the print length. (2) As shown in FIG. 7, one of the upper side and the lower side of the pull roll 11 rotating at a constant speed is moved up and down according to the printing length. In the example of FIG. 7, the sheet 3 is nipped and pulled while the lower pull roll 11 is rising, and the sheet 3 is stopped during the lowering. Therefore, since the printing is performed only while the sheet 3 is running, the pull roll 1 can be printed according to the desired printing length.
Change the up / down timing of 1 and intermittently feed the sheet. (3) As shown in FIG. 8, one of the pull rolls 11 is
The tension member 22 of the sheet 3 is attached, and the surface peripheral speed is made to coincide with the surface peripheral speed of the printing plate 14 (that is, the outer diameter D of the pull roll 11 and the plate cylinder 5 are the same and they rotate synchronously).
The arc length dimension of the tension member 22 is equal to or larger than the arc length dimension of the printing plate 14.

[0006]

The above-mentioned prior art has the following problems. Prior art (1): This method is the most commonly used method, but the work of exchanging the plate cylinder every time the printing length changes is complicated, and the printing mechanism becomes complicated. Further, the biggest drawback is that a large number of expensive plate cylinders having different circumferential dimensions, that is, diameters D ₁ , must be prepared, and the manufacturing cost of the printing sheet becomes high. Prior art (2): This method is an improvement measure for compensating the problem of the above (1) (no need to replace the plate cylinder). However, since the sheet is nipped and pulled and the printing surface of the sheet printed in the previous step is pressed, the ink that has not dried and adhered to the sheet surface is completely stripped off, or the printing surface is pulled by the ink on the pull roll surface. May get dirty. Further, raising and lowering a roll having a large inertia at a high frequency causes mechanically unreasonable and causes mechanical vibration, which cannot follow high-speed operation. Prior art (3): This method is also an improvement measure for compensating the problem of the above (1) (no need to replace the plate cylinder). However, as in (2) above, the sheet is clamped and pulled, so (2)
It has the same drawbacks as. Further, the tension member needs to be replaced every time the print length changes, and it is necessary to prepare a large number of tension members having different arc length dimensions.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an intermittent feeding device for a continuous sheet, which does not require plate cylinder replacement when changing the printing length and has less impact and wear.

[0008]

[Means for Solving the Problems]

(1) In order to accelerate and decelerate the seat, a tension member having a certain length is provided. (2) A feed roll is provided to allow the sheet to run at a constant speed. (3) In order to hold the sheet when the sheet is stopped,
Provide a holding roll.

[0009]

[Action]

(1) The contact length of the tension member with the printing surface is reduced within the repeated feeding length. (2) The shortening of the tension member reduces the rate of change in the feed length due to wear of the tension member. (3) By maintaining the tension when the seat is stopped, the fluctuation in tension during running and when stopped is reduced. (4) Intermittent sheet feeding is stable, which improves print quality.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall side view of an embodiment of the present invention in a flexographic rotary press, and FIGS. 2 to 4 are operation explanatory views of the present invention. In FIG. 1, a roll-shaped sheet 1, a rewinding machine 2,
Printing unit 10, (plate cylinder 5, impression cylinder 6, inking roller 7,
Ink reservoir 8, doctor blade 9, printing plate 14, ink 21) rolled-up sheet 12, winding machine 13
Is the same as the conventional one. In the intermittent feeding apparatus for continuous sheets according to the present invention, the pull roll unit 11 is further provided with tension members 22 and 24 having a constant length, a feed roll 15, a holding roll 16, a cam shaft 19 and a cam 18.

The movement of the sheet 3 in the pull roll unit 11 will be described with reference to FIGS. In the pull roll unit 11, the drum 26, the drag roll 27, the feed roll 15,
The holding roll 16 and the cam shaft 19 rotate at a constant speed in the direction of the arrow via a motor gear (not shown), and the surface speed of the drum 26, the tension members 22, 24, the feed roll 15, and the holding roll 16. Are also rotating at the same speed.

At this time, considering the movement of the seat 3, FIG.
As shown in FIG. 3, by sandwiching the sheet 3 between the drum 26 and the tension member 22 having a fixed length attached to the drag roll 27, the tension force F ₁ of the sheet by the tension member 22 acts and the sheet 3 is The surface speed of the tension member 22 coincides with the surface speed of the tension member 22, and accelerated traveling is started. Next, as shown in FIG. 3, when the tension member 22 is rotated to a predetermined position (the sheet 3 is accelerated and runs at a constant speed), the cam follower 17 provided on the arm 20 for the feed roll 15 is attached to the cam shaft 19. It falls off from the outer circumference of the attached cam 18. At the same time, the feed roll 15 descends to sandwich the sheet 3 with the drum 26, the sheet pulling force F ₂ by the feed roll 15 acts, and the sheet 3 running by the tension member 22 is held and the sheet runs at a constant speed. To do. Feed roll 15 here
Is constantly pressed by the air cylinder 23 (or a spring or the like). The feed rolls 15 are one or a combination of a plurality of feed rolls 15 in the width direction, and have a structure in which the position of the feed roll 15 can be adjusted in the width direction of the sheet 3 so that a position free from printing stains can be arbitrarily set. (Not shown) Further, the cam 18 attached to the cam shaft 19 is also a combination of one or a plurality of cams, and the arc length dimension l ₁ of the cam 18 can be adjusted with respect to the repeated feed length change. It has a simple structure. After the sheet 3 further travels (not shown), as shown in FIG. 4, when the cam follower 17 is pushed up by the cam 18 provided on the cam shaft 19, the feed roll 15 also rises and separates from the sheet 3, Although the pulling force F ₂ due to the feed roll 15 disappears, the running of the sheet is continued by the pulling force F ₅ due to the pulling member 24. The tension member 24 has a structure that can be adjusted in the circumferential direction according to the repeated feed length (not shown). When the drag roll 27 further rotates and the tension member 24 separates from the sheet 3, the sheet 3 enters the printing unit. The seat 3 is instantaneously stopped by a brake device (not shown) (brake force = F ₃ ) installed on the side. A holding roll 16 is provided to hold the sheet tension while the sheet is stopped. The sheet tension is held by the sheet pulling force F ₄ by the holding roll 16 in the state of sliding friction between the surface of the holding roll 16 and the contact surface between the sheet 3. The holding roll 16 is constantly pressed by the air cylinder 23 (or a spring or the like). The holding roll 16 is composed of one or plural holding rolls in the width direction, and the position of the holding roll 16 can be adjusted in the width direction of the sheet 3, so that a position free from printing stains can be arbitrarily obtained. (Not shown) If the drag roll 27 further rotates and the tensile force of the tension member 22 acts (FIG. 2),
The seat 3 starts traveling again. The relationship of the force applied to the seat 3 is as follows: F ₁ <F ₃ during acceleration traveling → F ₂ > F during constant speed traveling
₃ → The structure is such that each tension part and the brake device can be adjusted so that F ₅ > F ₃ during deceleration traveling → F ₄ <F ₃ when the seat is stopped. The seat 3 intermittently runs by repeating this sequence.

F _{1 to} F ₅ are tensile or braking forces acting on the sheet 3, F ₁ : tensile force by the tension member 22 F ₂ : tensile force by the feed roll 15 F ₃ : braking force F ₄ : holding roll Tensile force by 16 F ₅ : Tensile force by the tension member 24.

[0014]

【The invention's effect】

(1) By using the tension member only when accelerating and decelerating the sheet and using the feed roll at constant speed, the contact length of the tension member on the printing surface within the repeated feed length is reduced, and the printing restriction range due to contact is reduced. Become. (2) By using a short tension member having a constant length, the rate of change in the feed length due to wear of the tension member is small.
(When the sheet is pulled only by the tension member as in the prior art shown in FIG. 8, the rate of change in the repeated feed length due to wear is large.) (3) Two pieces of constant length adjustable in the circumferential direction at all times Since a desired repetitive feed length can be obtained for the member and the feed roll, it is not necessary to prepare a large number of tension members and replace each time the repetitive feed length is changed, and the manufacturing cost of the printing sheet is reduced. Further, the tension member can be manufactured by a machine maker as a mechanical part with high accuracy and high durability. It is almost impossible to supply a tension member according to the production contents (a large number of repeated feed lengths) of a machine user as in the prior art (FIG. 8), and even if possible, it is very expensive and the manufacturing cost of the printing sheet is high. To rise. (4) By holding a sheet other than the printing surface in the sheet width direction with a holding roll when the sheet is stopped, the sheet is held with a predetermined tension even when the sheet is stopped. Since it can be held with the tension of, the influence of sheet tension fluctuation caused by intermittent feeding is reduced. Therefore, this can improve the accuracy of the repeated feed length.

[Brief description of drawings]

FIG. 1 is an overall layout diagram of an embodiment of the present invention.

FIG. 2 is a side view showing a state during acceleration of a pull roll portion in FIG.

FIG. 3 is a drawing similar to FIG. 2 showing a state at constant speed feeding.

FIG. 4 is a drawing similar to FIG. 2 showing a state during deceleration.

FIG. 5 is an overall layout diagram of a general sheet continuous traveling type flexographic rotary press.

FIG. 6 is a detailed view of the printing unit in FIG.

FIG. 7 is a configuration diagram of a conventional pull roll portion.

FIG. 8 is a configuration diagram of another conventional pull roll portion.

[Explanation of symbols]

 3 sheet 11 pull roll 15 feed roll 16 holding roll 22 tension member 24 tension member 26 drum 27 drag roll

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayuki Masatoki 1-chome, Kotobukicho, Mihara-shi, Hiroshima Mihara Rishige Engineering Co., Ltd.

Claims (1)

[Claims] 1. A drum for winding and guiding a continuous sheet,
A drag roll having a pair of pulling members provided on the surface of the drum for contacting the sheet on the drum, and a feed roll and a holding roll for detachably contacting the sheet on the drum are provided. An intermittent feeding device for a continuous sheet, characterized in that the sheet is accelerated and decelerated, the feeding roll feeds the sheet at a constant speed, and the holding roll holds the sheet tension when the sheet is stopped.