Paper web feed unit used in a rotary press and equipped with a paper web traveling tension controller

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a paper web feed unit used in a rotary press and equipped with a paper web traveling tension controller, and more particularly to a paper web feed unit which is used in a rotary press and in which a paper web having a width double that of paper used in a press unit is longitudinally cut, by use of cutting means, into two cut paper webs having substantially the same width; only one of the cut paper webs is passed through an angle bar section; and the traveling tension of each cut paper web is controlled by use of a paper web traveling tension controller.

2. Description of the Related Art

Japanese Patent Publication (kokoku) No. 51-007083 discloses a conventional rotary press in which a paper web is longitudinally cut, by use of cutting means, into two cut paper webs having substantially the same width; the first cut paper web is fed to a first press unit via an angle bar section; and the second cut paper web is fed directly to a second press unit without passing through the angle bar section.

In the rotary press, while the first cut paper web passes through the angle bar section, the traveling path thereof is transferred such that the first cut paper web is fed to the first press unit in a state in which the center line thereof is aligned with the center line of the second cut paper web that is fed to the second press unit.

Further, a traveling tension controller as disclosed in “Newspaper Printing Handbook,” pp. 111-112, published by Japanese Newspapers Association, Apr. 10, 1997 (§3 “Newspaper Offset Rotary Press,” (2) Infeed Tension) has generally been used to control the traveling tension of a paper web fed to a press unit.

The traveling tension controller is used to stabilize the traveling tension of a paper web fed to a press unit and is designed to control the traveling tension of the paper web at a location before the press unit by use of an infeed roller and a dancer roller.

FIG. 4

shows such a traveling tension controller combined with the above-described rotary press.

In

FIG. 4

, a paper web WO′ having a width double that of paper used in an unillustrated press unit of a rotary press is taken out of a paper roll W′ and is longitudinally cut, by use of cutting means C′, into two cut paper webs having substantially the same width. Subsequently, a first cut paper web W

1

′ of a single width is passed through an angle bar section D′, so that the center line of the first cut paper web W

1

′ coincides with the center line of a second cut paper web W

2

′ of a single width.

For the cut paper webs W

1

′ and W

2

′, paper web traveling tension controllers T

1

and T

2

are provided in order to enable the cut paper webs W

1

′ and W

2

′ to be fed to respective press units while their traveling tensions are controlled independently.

The paper web traveling tension controller T

1

(T

2

) includes a dancer roller

42

a

(

42

b

) connected to a fluid cylinder

41

a

(

41

b

). The dancer roller

42

a

(

42

b

) applies a pushing pressure to the cut paper web W

1

′ (W

2

′) due to projection of the piston rod of the fluid cylinder

41

a

(

41

b

), and moves in accordance with variation in the traveling tension of the cut paper web W

1

′ (W

2

′).

Further, an infeed roller

43

a

(

43

b

) driven by a drive source

45

a

(

45

b

) is provided upstream of the dancer roller

42

a

(

42

b

); and a sensor

44

a

(

44

b

) for detecting the position of the dancer roller

42

a

(

42

b

) is attached to the fulcrum of a support arm of the dancer roller

42

a

(

42

b

). The drive source

45

a

(

45

b

) receives a detection signal from the sensor

44

a

(

44

b

) and changes the circumferential speed of the infeed roller

43

a

(

43

b

) in order to control the amount of the paper web fed to the dancer roller

42

a

(

42

b

) such that the dancer roller

42

a

(

42

b

) is always located at a neutral position (ordinary position) in the slack/tension direction of the cut paper web W

1

′ (W

2

′).

Thus, a stable traveling tension is applied to the cut paper web W

1

′ (W

2

′) fed to the press unit.

The above-described conventional techniques involve various drawbacks, as described below.

In the rotary press disclosed in Japanese Patent Publication No. 51-007083, no paper web traveling tension controller is provided in a paper threading path extending from the cutting means of the paper web feed unit where a paper web taken out of the paper roll is cut to the press unit. Therefore, when the traveling tension of the cut paper web changes (for example, decreases) due to resistance of rollers for supporting and guiding the cut paper web and a paper dragging operation performed downstream of the press unit, the traveling cut paper web slacks and meanders, resulting in paper breakage or other problems. On the contrary, when the traveling tension of the cut paper web increases, wrinkles are generated in the traveling cut paper web, also resulting in paper breakage or other problems.

In order to overcome the above-mentioned drawbacks, as shown in

FIG. 4

, the above-described paper web traveling tension controller is combined with the rotary press disclosed in Japanese Patent Publication No. 51-007083. However, the rotary press shown in

FIG. 4

has a drawback in that a difference in traveling state is produced between the cut paper web W

1

′—which travels from the cutting means C′ to the infeed roller

43

a

along a paper threading path containing an angle bar section D′ which generates extremely high friction resistance—and the cut paper web W

2

′—which travels from the cutting means C′ to the infeed roller

43

b

along a paper threading path containing no angle bar section.

That is, when the rotary press is started and the supply of cut paper webs W

1

′ and W

2

′ to the respective press units is started at the same paper speed by means of paper drag rollers (not shown) provided downstream of the press units, the dancer rollers

42

a

and

42

b

of the paper web traveling tension controllers T

1

and T

2

start to move in the tensing direction of the cut paper webs W

1

′ and W

2

′ (rightward in

FIG. 4

) as the traveling tensions of the cut paper webs W

1

′ and W

2

′ increase. However, due to the action of the infeed rollers

43

a

and

43

b

, the dancer rollers

42

a

and

42

b

are controlled to return to the respective neutral positions (ordinary positions).

In the above-described case, since the cut paper web W

1

′ is subjected to the high friction resistance of the angle bar section D′, the cut paper web W

1

′ elastically deforms and stretches in a region between the angle bar section D′ and the infeed roller

43

a

, and thus travels slightly slower than the cut paper web W

2

′ in a region between the cutting means C′ and the angle bar section D′. As a result, in the region between the cutting means C′ and the angle bar section D′, a difference in traveling tension is produced between the cut paper web W

1

′ and the cut paper web W

2

′, with the result that the cut paper web W

1

′ slacks.

However, when the rotary press is operated continuously, the difference between the traveling tension of the cut paper web W

1

′ in the region between the cutting means C′ and the angle bar section D′ and the traveling tension of the cut paper web W

1

′ in the region between the angle bar section D′ and the infeed roller

43

a

converges to a constant value determined from the friction resistance between the angle bar section D′ and the cut paper web W

1

′, and in this state, the cut paper web W

1

′ starts to travel at substantially the same speed as the cut paper web W

2

′. Therefore, no significant problems occur.

However, when low speed operation and stoppage of the rotary press are performed repeatedly many times within a short period of time; for example, in a work step in which an operator attaches a printing plate onto a plate cylinder, the difference between the traveling tension of the cut paper web W

1

′ in the region between the cutting means C′ and the angle bar section D′ and that in the region between the angle bar section D′ and the infeed roller

43

a

does not converge to a constant value, even though the rotation of the infeed roller

43

a

is controlled such that the dancer roller

42

a

returns to the neutral (ordinary) position. In this case, the cut paper web

1

′ travels intermittently, with the result that the amount of slack in the cut paper web W

1

′ at a region downstream of the cutting means C′ increases.

By contrast, unlike the cut paper web W

1

′, the cut paper web W

2

′ does not slack, with the result that at a location where the cutting means C′ cuts the paper web W

0

′, the cut paper web W

2

′ comes into a slightly pulled state as compared to the cut paper web W

1

′.

Therefore, a cut line formed by the cutting means C′ meanders or skews slightly.

When the cut paper web W

1

′ and the cut paper web W

2

′ are caused to travel simultaneously upon a speed increasing operation after start of printing, a large difference in traveling tension is suddenly produced between the cut paper web W

1

′ and the cut paper web W

2

′ in a region immediately after the cutting means C′, with the result that one or both of the cut paper webs W

1

′ and W

2

′ is broken, and a slacked portion of the cut paper web W

1

′ is caught by the cutting means C′ or other rollers, which stops the operation.

Accordingly, there has been a strong desire for a paper web traveling tension controller which can be used in the structure in which a paper web taken out of a paper roll is longitudinally cut, by means of cutting means, into two cut paper webs having substantially the same width, and one of cut paper webs is passed through an angle bar section in order to transfer the traveling path of the cut paper web; which prevents sudden generation of a large difference in traveling tension between the two cut paper webs which would otherwise be generated in a region downstream of the cutting means when the rotary press is operated intermittently at slow speed; and which does not cause any problem during continuous operation of the rotary press.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a paper web feed unit used in a rotary press and equipped with a paper web traveling tension controller which prevents sudden generation of a large difference in traveling tension between two cut paper webs which would otherwise be generated in a region downstream of the cutting means when the rotary press is operated intermittently at slow speed, and which does not cause any problem during continuous operation of the rotary press.

The present invention provides a paper web feed unit used in a rotary press in which a paper web taken out of a paper roll passes through the paper web feed unit and a press unit along a paper threading path having guide rollers. The paper web feed unit comprises feed-out means, cutting means, an angle bar section, and a paper web traveling tension controller. The feed-out means is rotated by drive means and is adapted to feed to a downstream side the paper web wound around the outer circumferential surface of the feed-out means, by means of frictional force between the outer circumferential surface of the feed-out means and the paper web. The cutting means cuts the traveling paper web into first and second cut paper webs having substantially the same width. The angle bar section comprises angle bars around which only the first cut paper web is wound, so that the traveling path of the first cut paper web is transferred. The paper web traveling tension controller controls the traveling tensions of the first and second cut paper webs in a region downstream of the angle bar section.

The paper web traveling tension controller comprises dancer roller means, detection means, and control means. The dance roller means comprises a first rotatable dancer roller around which the first cut paper web passing through the angle bar section is wound, and a second rotatable dancer roller around which the second cut paper web not passing through the angle bar section is wound. The first and second dancer rollers can move in a synchronized manner in order to change the lengths of respective traveling paths along which the first and second cut paper webs travel, and a predetermined pushing pressure is applied to each of the first and second dancer rollers in a direction for increasing the length of the traveling path of the corresponding cut paper web. The detection means detects the positions of the first and second dancer rollers. The control means receives a detection signal output from the detection means and outputs a control signal to the drive means in order to control the rotational frequency of a driven roller of the feed-out means to thereby maintain each of the first and second dancer rollers at a constant position.

Preferably, the dancer roller means further comprises a first movable arm having a free end which rotatably supports the first dancer roller, a second movable arm having a free end which rotatably supports the second dancer roller, pressing means for individually applying a pushing pressure to each of the first and second movable arms in order to move the corresponding dancer roller toward a direction for increasing the length of the traveling path of the cut paper web wound around the corresponding dancer roller, and a link for coupling the first and second movable arms to each other such that the first and second dancer rollers move simultaneously in a synchronized manner; and the detection means detects positions of the first and second dancer rollers through detection of an angular position of one of the first and second movable arms.

Preferably, the angle bar section comprises two parallel bars which are disposed with a predetermined distance therebetween such that the bars skew with respect to the driven roller, whereby the traveling path of the first cut paper web wound around the bars is transferred to become parallel to the traveling path of the second cut paper web not passing through the angle bar section.

In the paper web feed unit according to the present invention, no large difference in traveling tension is produced between the first cut paper web and the second cut paper web in a region right downstream the cutting means, even when the press units are intermittently operated at low speed.

As a result, even when the rotary press is intermittently operated at low speed for preparation of the regular operation, and subsequently the speed of the rotary press is increased upon start of the regular operation, no large difference in traveling tension is produced between the two cut paper webs, so that the two cut paper webs travel smoothly to the respective press units.

Accordingly, it becomes possible to prevent occurrence of problems such as web breakage during regular operation of the rotary press, to thereby reduce the amount of spoilage and the amount of labor required for troubleshooting.

BRIEF DESCRIPTION OF THE DRAWINGS

Various other objects, features and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description of the preferred embodiment when considered in connection with the accompanying drawings, in which:

FIG. 1

is a front view of a paper web traveling tension controller according to an embodiment of the present invention;

FIG. 2

is a side view as viewed from the direction of arrow II in

FIG. 1

;

FIG. 3

is a view showing the structure of a rotary press equipped with the paper web traveling tension controller shown in

FIG. 1

; and

FIG. 4

is a front view of a conventional paper web traveling tension controller for a rotary press.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A paper web feed unit used in a rotary press and equipped with a paper web traveling tension controller according to an embodiment of the present invention will next be described with reference to the drawings.

As shown in

FIG. 3

, an exemplary rotary press P comprises a plurality (two in this example) of press units R disposed above a paper web feed unit Q provided on a base

70

, and a folding unit S having drag rollers

50

is disposed adjacent to the press units R.

The paper web feed unit Q comprises a paper roll support provided on an unillustrated frame and adapted to rotatably support a paper roll W. The paper web feed unit Q further comprises feed-out means A, an angle bar section D, and a paper web traveling tension controller T, which are provided in this sequence from the lower side to the upper side of frames provided on the base

70

. The feed-out means A has cutting means C and is driven by drive means B.

The paper roll support, the feed-out means A, the angle bar section D, the paper web traveling tension controller T, the press units R, the folding unit S, and guide rollers provided therebetween form two paper threading paths.

In the rotary press P, while following the paper threading paths, a paper web W

0

taken out of the paper roll W passes through the feed-out means A having the cutting means C, the angle bar section D, the paper web traveling tension controller T, and the press units R, and then reaches the folding unit S. More specifically, the paper web W

0

having a width double that of paper used in the press units R is longitudinally cut, by the cutting means C, into two cut paper webs W

1

and W

2

having substantially the same width. Only the first cut paper web W

1

is passed through the angle bar section D, where the traveling path of the first cut paper web W

1

is transferred such that the first cut paper web W

1

is aligned widthwise with the second cut paper web W

2

.

Subsequently, the cut paper webs W

1

and W

2

are caused to travel to the respective press units R, while their traveling tensions are controlled by the paper web traveling tension controller T. After being printed in the press units R, the cut paper webs W

1

and W

2

are superposed on each other and fed to the folding unit S by means of the drag rollers

50

. In the folding unit S, the cut paper webs W

1

and W

2

are cut to predetermined lengths, and cut paper sheets are folded in the form of a signature, which is then discharged from the folding unit S.

The paper web feed unit Q will be described in more detail with reference to

FIGS. 1 and 2

. Frames

30

and

31

—which support the paper web traveling tension controller T, the angle bar section D, and the feed-out means A equipped with the cutting means C—are disposed on the base

70

such that the frames

30

and

31

face each other with a distance therebetween greater than the width of the paper web W

0

, and two parallel stays

34

are disposed between the upper ends of the frames

30

and

31

.

Another frame

33

is disposed on the upper end of the frame

31

to extend upward therefrom, and yet another frame

32

facing the frame

33

is provided to straddle the stays

34

at a position offset toward the frame

30

from the center between the frames

30

and

31

.

The above-described feed-out means A, the drive means B, and the cutting means C are disposed between the frames

30

and

31

. The feed-out means A has a driven roller

2

for feeding to the downstream side the paper web W

0

taken out of the paper roll W of the paper roll support. The drive means B drives the driven roller

2

. The cutting means C cuts the paper web W

0

longitudinally into two cut paper webs W

1

and W

2

having substantially the same width. The above-described angle bar section D for transferring the traveling path of the first cut paper web W

1

is disposed across the space between the frames

30

and

31

and the space between the frames

32

and

33

.

Further, dancer roller means E and detection means F are provided between the frames

30

and

31

. The dancer roller means E comprises dancer rollers

5

a

and

5

b

and fluid cylinders

8

a

and

8

b

which produce pushing pressures from the piston rods thereof. The pushing pressures are applied via the dancer rollers

5

a

and

5

b

to the cut paper web W

1

passing through the angle bar section D and the cut paper web W

2

not passing though the angle bar section D. The detection means F detects the positions of the dancer rollers

5

a

and

5

b

. Further, control means G is provided at an appropriate position. The control means G receives a detection signal output from the detection means F and outputs a control signal to the drive means B in order to control the rotational frequency of the driven roller

2

of the feed-out means A such that each of the dancer rollers

5

a

and

5

b

is maintained at a constant position; i.e., at an ordinary position.

Next, each of the above-described means A-G will be described in further detail.

In the feed-out means A, the opposite end portions of a rotation shaft

1

concentrically integrated with the driven roller

2

are rotatably supported by the frames

30

and

31

, and one end portion projects outward from the frame

30

as a projected end portion

1

a

. An annular groove is formed circumferentially in the outer surface of the driven roller

2

at an axially central position such that a disk blade

4

a

of the cutting means C, which will be described later, can enter the groove.

Between the driven roller

2

and the paper roll support, a guide roller

61

is disposed parallel to the driven roller

2

at a position close thereto, and the opposite shaft end portions of the guide roller

61

are rotatably supported by the frames

30

and

31

.

The drive means B comprises a motor

3

attached to the outer wall of the frame

30

via a bracket

3

a

. The output shaft of the motor

3

is connected to the projected end portion

1

a

of the rotation shaft

1

via a shaft coupling.

The cutting means C comprises a block

4

which rotatably supports the shaft of the disk blade

4

a

and is equipped with a motor for rotating the shaft in a manner interlocked with the operation of the rotary press. The block

4

is attached to the frames

30

and

31

via an unillustrated bracket such that the circumferential cutting edge of the disk blade

4

a

can enter and exit from the annular groove of the driven roller

2

. When the disk blade

4

a

is rotated by the motor

3

in a state in which the circumferential cutting edge of the disk blade

4

a

is located in the annular groove of the driven roller

2

, the paper web W

0

, which travels while being supported by the outer circumferential surface of the driven roller

2

, is divided into two portions having substantially the same width.

As shown in

FIG. 2

, the angle bar section D comprises two parallel bars

51

and

52

disposed with a predetermined distance therebetween such that the bars

51

and

52

skew with respect to the driven roller

2

and extend across the space between the frames

30

and

31

and the space between the frames

32

and

33

. Specifically, the first ends of the bars

51

and

52

are attached, via attachment members

54

, to a shaft

53

whose opposite ends are supported by the frames

30

and

31

, and the second ends of the bars

51

and

52

are attached, via attachment members

56

, to a shaft

55

whose opposite ends are supported by the frames

32

and

33

.

Each of the attachment members

54

and

56

is movable in the axial direction and can be fixed in at least one desired position, and the first and second ends of the bars

51

and

52

are coupled to the attachment members

54

and

56

. Therefore, the distance between and inclination of the bars

51

and

52

can be adjusted.

The attachment members

54

are positioned on the shaft

53

such that one attachment member

54

is located at the approximate center of the shaft

53

, and the other attachment member

54

is located to substantially correspond to the outer edge of the cut paper web W

1

. The attachment members

56

are positioned on the shaft

55

such that one attachment member

56

is located to substantially correspond to the outer edge of the cut paper web W

2

, and the other attachment member

56

is located to substantially correspond to the cut edge of the cut paper web W

2

.

Accordingly, since the cut paper web W

1

is turned by and wound around the bars

51

and

52

, the traveling direction of the cut paper web W

1

is changed by the bar

51

to a direction corresponding to the inclination of the bar

51

and then changed by the bar

52

to a direction parallel to the traveling direction of the cut paper web W

2

(see FIG.

2

).

Between the driven roller

2

and the shaft

53

, guide rollers

62

and

63

are disposed parallel to the driven roller

2

, and the opposite shaft end portions of the guide rollers

62

and

63

are rotatably supported by the frames

30

and

31

. Each of the guide rollers

61

,

62

, and

63

functions as a snub roller for increasing the winding angle of the paper web around the driven roller

2

.

The dancer roller means E comprises parallel rotation shafts

6

a

and

6

b

which are disposed horizontally while being vertically separated from each other, the opposite ends of the rotation shafts

6

a

and

6

b

being supported by the frames

32

and

33

. The base end portions of movable arms

7

a

directed upward are integrally attached to the opposite end portions of the rotation shaft

6

a

, so that the movable arms

7

a

create angular displacements together with the rotation shaft

6

a

. Similarly, the base end portions of movable arms

7

b

directed upward are integrally attached to the opposite end portions of the rotation shaft

6

b

, so that the movable arms

7

b

create angular displacements together with the rotation shaft

6

b.

The shaft of the dancer roller

5

a

is supported by the free ends of the movable arms

7

a

, and the shaft of the dancer roller

5

b

is supported by the free ends of the movable arms

7

b.

The fluid cylinders (air cylinders)

8

a

and

8

b

are provided for the movable arms

7

a

and

7

b

to be located on the side where the frame

33

is present. The projection end of the piston rod of the fluid cylinders

8

a

is pin-connected to an intermediate portion of the movable arm

7

a

via a coupling member

10

, and the projection end of the piston rod of the fluid cylinders

8

b

is pin-connected to an intermediate portion of the movable arm

7

b

via another coupling member

10

. The base end portions of the fluid cylinders

8

a

and

8

b

are pivotally supported by shaft pins

9

a

and

9

b

which are attached to the frame

33

to project toward the inner side of the frame

33

. That is, the movable arms

7

a

and

7

b

and the fluid cylinders

8

a

and

8

b

can create angular displacements about parallel axes.

Further, coupling members

12

a

and

12

b

are attached to the intermediate portions of the movable arms

7

a

and

7

b

such that the coupling members

12

a

and

12

b

project toward the side opposite the fluid cylinders

8

a

and

8

b

. The opposite ends of a connecting rod

11

are coupled to the coupling members

12

a

and

12

b

via pins

13

a

and

13

b.

In the above-described configuration, the movable arms

7

a

and

7

b

, the coupling members

12

a

and

12

b

, and the connecting rod

11

constitute a link, and further constitute a link mechanism together with the rotation shafts

6

a

and

6

b

and the pins

13

a

and

13

b

. Accordingly, the dancer roller

5

a

and the dancer roller

5

b

move simultaneously in an interlocked manner.

Compressed air of a predetermined constant pressure is supplied from, for example, a compressed air supply pipe (not shown) to the fluid cylinders

8

a

and

8

b

, so that their piston rods project under pressure.

In the dancer roller means E, paired lower and upper guide rollers

21

and

22

are provided on one side (right side in

FIG. 1

) of the dancer roller

5

a

where the fluid cylinder

8

a

is present, and paired lower and upper guide rollers

23

and

24

are provided on one side (right side in

FIG. 1

) of the dancer roller

5

b

where the fluid cylinder

8

b

is present.

The guide rollers

21

and

22

are arranged such that the cut paper web W

1

wound therearound travels toward the dancer roller

5

a

from the side of the fluid cylinder

8

a

(from the right side in FIG.

1

), travels along the dancer roller

5

a

from the lower side to the upper side, and reverses direction to travel toward the side of the fluid cylinder

8

a

(toward the right side in FIG.

1

). Similarly, the guide rollers

23

and

24

are arranged such that the cut paper web W

2

wound therearound travels toward the dancer roller

5

b

from the side of the fluid cylinder

8

b

(from the right side in FIG.

1

), travels along the dancer roller

5

b

from the lower side to the upper side, and reverses direction to travel toward the side of the fluid cylinder

8

b

(toward the right side in FIG.

1

).

Through the action of the fluid cylinders

8

a

and

8

b

, their piston rods tend to project appropriately. Therefore, when the traveling tensions of the cut paper webs W

1

and W

2

decrease, the movable arms

7

a

and

7

b

swing appropriately, so that the dancer rollers

5

a

and

5

b

move in a direction for increasing the length of the traveling path of the cut paper web W

1

between the adjacent guide rollers

21

and

22

and the length of the traveling path of the cut paper web W

2

between the adjacent guide rollers

23

and

24

. When the traveling tensions of the cut paper webs W

1

and W

2

increase, the movable arms

7

a

and

7

b

swing appropriately, so that the dancer rollers

5

a

and

5

b

move in a direction for decreasing the length of the traveling path of the cut paper web W

1

between the adjacent guide rollers

21

and

22

and the length of the traveling path of the cut paper web W

2

between the adjacent guide rollers

23

and

24

.

In the dancer roller means E, the two dancer rollers

5

a

and

5

b

; i.e., the two movable arms

7

a

and

7

b

, move in an interlocked manner. Therefore, in the detection means F, a potentiometer

14

attached to the frame

32

is connected to an end portion of one of the two rotation shafts

6

a

and

6

b

(the rotation shaft

6

b

in the illustrated example), the end portion projecting outward from the frame

32

. Thus, the potentiometer

14

detects the rotational position of the rotation shaft

6

b

; i.e., the angular position of the movable arm

7

b

. Through detection of the angular position of the movable arm

7

b

, the position of the dancer roller

5

b

and the position of the dancer roller

5

a

interlocked with the dancer roller

5

b

can be determined.

As described above, since the two dancer rollers

5

a

and

5

b

; i.e., the two movable arms

7

a

and

7

b

, are interlocked with each other, traveling tension can be adjusted through use of the potentiometer

14

connected to either the rotation shaft

6

a

or the rotation shaft

6

b

, even in the case where a paper web is taken out of a roll paper having a width that can be used as is in the press unit R and is passed through a paper threading path for the cut paper web W

2

(a paper threading path that does not pass through the angle bar section D) shown in

FIG. 1

to be fed to the press unit R.

The control means G is disposed at an appropriate position. The control means G is connected to the detection means F in order to receive a detection signal from the detection means F and is connected to the drive means B in order to output a control signal in accordance with the detection signal.

In addition to the above-described guide rollers

21

,

22

,

23

,

24

,

61

, and

62

, other guide rollers are appropriately provided in order to define the traveling paths of the cut paper webs W

1

and W

2

.

In the illustrated example, a guide roller

64

is provided between the bar

52

and the guide roller

21

; a guide roller

65

is provided between the guide roller

62

and the guide roller

23

; and guide rollers

66

and

67

are provided downstream of the guide roller

24

.

The operation of the paper web feed unit of the above-described rotary press will next be described.

Before startup of the rotary press shown in

FIG. 3

, the paper roll W is attached to the paper web feed unit Q, and the paper web W

0

taken out of the paper roll W and having a width double that used in the press units R is threaded, by means of an unillustrated threading apparatus or an operator, along the threading path extending from the paper web feed unit Q to the folding unit S via the press units R.

That is, as shown in

FIG. 1

, the paper web W

0

is wound around the roller

2

of the feed-out means A operated upon startup of the rotary press P, and is longitudinally cut, by the action of the disk blade

4

a

of the cutting means C, into two cut paper webs W

1

and W

2

having substantially the same width.

The first cut paper web W

1

is passed through the bars

51

and

52

of the angle bar section D, so that the center line of the first cut paper web W

1

coincides with the center line of the second cut paper web W

2

. Subsequently, the first cut paper web W

1

is engaged with the guide roller

21

, wound around the dancer roller

5

a

of the dancer roller means E, and then engaged with the guide roller

22

to thereby complete the threading operation for the cut paper web W

1

.

The second cut paper web W

2

is engaged with the guide roller

23

, wound around the dancer roller

5

b

of the dancer roller means E, and then engaged with the guide roller

24

to thereby complete the threading operation for the cut paper web W

2

.

The thus-threaded cut paper webs W

1

and W

2

are passed through the respective press units R, superposed on each other, and then fed to the folding unit S by means of the drag rollers

50

(see FIG.

3

).

Upon startup of the rotary press P, the threaded cut paper webs W

1

and W

2

are caused to travel. Subsequently, the speed of the rotary press P is increased in order to start printing, so that the speed of the cut paper web W

1

traveling to the corresponding press unit R and the speed of the cut paper web W

2

traveling to the corresponding press unit R increase, and a difference is produced between the speed at which the cut paper webs W

1

and W

2

travel to the press units R and the speed at which the paper web W

0

(cut paper webs W

1

and W

2

) is fed out by the feed-out means A. Therefore, in a region downstream of the feed-out means A, the traveling tensions of the cut paper webs W

1

and W

2

increase independently of each other.

Generally, the traveling tension of the cut paper web W

1

passing through the angle bar section D is higher than that of the cut paper web W

2

, due to the influence of the angle bar section D.

Therefore, as the traveling tension increases, the dancer roller

5

a

—around which the cut paper web W

1

is wound—moves toward the tensing direction of the cut paper web W

1

(toward the right in FIG.

1

), against the pushing pressure that is applied to the dancer roller

5

a

from the piston rod of the fluid cylinder

8

a

via the movable arm

7

a

. As a result, the movable arm

7

a

creates a clockwise angular displacement in

FIG. 1

; i.e., a clockwise rotation of the rotation shaft

6

a

in FIG.

1

.

The clockwise angular displacement of the movable arm

7

a

is transmitted to the movable arm

7

b

via the link mechanism formed by the connecting rod

11

, the coupling members

10

, the shaft pins

9

a

and

9

b

, and the movable arms

7

a

and

7

b

, so that the movable arm

7

b

creates an angular displacement in synchronism with the movable arm

7

a

. Thus, the rotation shaft

6

b

rotates clockwise in

FIG. 1

in synchronism with the rotation shaft

6

a.

In response to the clockwise rotation of the rotation shaft

6

b

, control is performed in order to return the dancer rollers

5

a

and

5

b

to the respective neutral positions (ordinary positions) shown in FIG.

1

. That is, in order to make the traveling tensions of the cut paper webs W

1

and W

2

attain their center values, the feed-out speed at which the paper web W

0

(cut paper webs W

1

and W

2

) is fed by the feed-out means A is controlled in order to follow the speeds of the cut paper webs W

1

and W

2

traveling to the respective press units R.

The movements of the dancer rollers

5

a

and

5

b

stemming from variations in the traveling tension of the cut paper webs W

1

and W

2

are detected by the potentiometer

14

as a change in the angular position of the movable arm

7

b

; i.e., in the rotational angle position of the rotation shaft

6

b

. As described above, the detection signal output from the potentiometer

14

is supplied to the control means G. Upon receipt of the detection signal, the control means G controls the motor

3

of the drive means B in order to increase the rotational frequency of the driven roller

2

.

Since the circumferential speed of the driven roller

2

is increased through the above-described control, the feed-out speed of the paper web W

0

(the cut paper webs W

1

and W

2

) increases to follow the traveling speed of the cut paper webs W

1

and W

2

traveling to the respective press units R.

In this way, the traveling tensions of the cut paper web W

1

and W

2

in the dancer roller means E are decreased and maintained at a predetermined value. As a result, the dancer rollers

5

a

and

5

b

move leftward in

FIG. 1

until the potentiometer

14

detects that the movable arm

7

b

has returned to a neutral or center angular position, or that the rotation shaft

6

b

has returned to a neutral or center rotational angle position, so that the movable arm

7

b

creates a counterclockwise angular displacement to return to the neutral position (ordinary position).

In this case, needless to say, the dancer rollers

5

a

and

5

b

move in an interlocked manner.

Since the cut paper web W

1

is subjected to the high friction resistance of the angle bar section D during the traveling, the cut paper web W

1

elastically deforms and stretches in a region downstream of the angle bar section D, and thus travels slightly slower than the cut paper web W

2

in a region between the cutting means C and the angle bar section D. As result, in the region between the cutting means C and the angle bar section D, a difference in traveling tension is produced between the cut paper web W

1

and the cut paper web W

2

, with the result that the cut paper web W

1

slacks.

However, when the rotary press is operated continuously, the difference between the traveling tension of the cut paper web W

1

in the region between the cutting means C and the angle bar section D and the traveling tension of the cut paper web W

1

in the region downstream of the angle bar section D converges to a constant value determined from the friction resistance between the angle bar section D and the cut paper web W

1

, and in this state, the cut paper web W

1

starts to travel at the same speed as the cut paper web W

2

. Therefore, no significant problems occur.

By contrast, a problem may occur when the cut paper webs W

1

and W

2

slack in a region between the feed-out means A and the dancer roller means E and the traveling tensions of the cut paper webs W

1

and W

2

decrease independently. In this case, due to decreases in traveling tension, the dancer rollers

5

a

and

5

b

—around which the cut paper webs W

1

and W

2

are wound—move toward the slaking direction of the cut paper webs W

1

and W

2

(toward the left in

FIG. 1

) due to the pushing pressure applied to the dancer rollers

5

a

and

5

b

from the piston rods of the fluid cylinders

8

a

and

8

b

via the movable arms

7

a

and

7

b

. However, as described above, the traveling tension of the cut paper web W

1

passing through the angle bar section D is higher than that of the cut paper web W

2

, due to the influence of the angle bar section D. Therefore, the traveling tension of the cut paper web W

1

does not decrease sufficiently.

Accordingly, the movement of the dancer roller

5

a

—around which the cut paper web W

1

is wound—toward the slacking direction (toward the left in

FIG. 1

) is resisted to a greater extent as compared to the movement of the dancer roller

5

b.

However, the dancer roller

5

b

follows the movement of the dancer roller

5

a

toward the slacking direction (toward the left in FIG.

1

), because the movable arm

7

b

of the dancer roller

5

b

is connected to the movable arm

7

a

of the dancer roller

5

a

via the link mechanism, so that the movable arm

7

b

causes the same counterclockwise angular displacement (

FIG. 1

) as that of the movable arm

7

a.

In this way, control is effected for returning the dancer rollers

5

a

and

5

b

to the respective neutral positions (ordinary positions) shown in FIG.

1

. That is, the feed-out speed at which the paper web W

0

(the cut paper webs W

1

and W

2

) is fed out by the feed-out means A is controlled to follow the traveling speed of the cut paper webs W

1

and W

2

traveling to the respective press units R.

Specifically, as described above, the movements of the dancer rollers

5

a

and

5

b

stemming from variations in the traveling tension of the cut paper webs W

1

and W

2

are detected by the potentiometer

14

as a change in the angular position of the movable arm

7

b

; i.e., in the rotational angle position of the rotation shaft

6

b

, and the detection signal output from the potentiometer

14

is supplied to the control means G. Upon receipt of the detection signal, the control means G controls the motor

3

of the drive means B in order to decrease the rotational frequency of the driven roller

2

.

Since the circumferential speed of the driven roller

2

is decreased through the above-described control, the feed-out speed of the paper web W

0

(the cut paper webs W

1

and W

2

) decreases relative to the traveling speed of the cut paper webs W

1

and W

2

traveling to the respective press units R. Consequently, the traveling tensions of the cut paper web W

1

and W

2

in the dancer roller means E are increased and maintained at a predetermined value. As a result, the dancer rollers

5

a

and

5

b

move rightward in

FIG. 1

until the potentiometer

14

detects that the movable arm

7

b

has returned to the neutral or center angular position, or that the rotation shaft

6

b

has returned to the neutral or center rotational angle position, so that the movable arm

7

b

creates a clockwise angular displacement to return to the neutral position (ordinary position).

When low speed operation and stoppage of the rotary press are performed repeatedly many times within a short period of time; for example, in a work step in which an operator attaches a printing plate onto a plate cylinder, the traveling tensions of the cut paper webs W

1

and W

2

increase due to operation of the rotary press, so that the dancer rollers

5

a

and

5

b

move simultaneously toward the tensing direction of the cut paper webs W

1

and W

2

(rightward in FIG.

1

).

The press units of the rotary presses are designed to operate at the same speed and cause the cut paper webs W

1

and W

2

to travel at the same speed.

Accordingly, when the traveling tension applied from the cut paper web W

1

to the dancer roller

5

a

is compared with the traveling tension applied from the cut paper web W

2

to the dancer roller

5

b

, the traveling tension applied from the cut paper web W

1

to the dancer roller

5

a

is understood to be greater than that applied from the cut paper web W

2

to the dancer roller

5

b

, by an amount corresponding to a traveling delay caused by the friction resistance of the angle bar section D.

Therefore, the two dancer rollers

5

a

and

5

b

move in an interlocked manner in accordance with variation in the traveling tension of the cut paper web W

1

, and the cut paper web W

2

travels along the dancer roller

5

b

in a slightly slacked state.

Meanwhile, as described above, the cut paper web W

1

slacks in the region between the cutting means C and the angle bar section D, due to the friction resistance of the angle bar section D. The slack of the cut paper web W

1

generated in a limited region causes slack of the cut paper web W

2

which is cut from the paper web W

0

from which the cut paper web W

1

is also cut, with the result that the slack of the cut paper web W

1

and the slack of the cut paper web W

2

both occur at a location downstream and in the vicinity of the cutting means C.

Accordingly, even when the cut paper webs W

1

and W

2

are caused to travel simultaneously upon a speed increasing operation after the start of printing, no large difference in traveling tension is produced between the cut paper webs W

1

and W

2

in a region immediate after the cutting means C, so that both the cut paper web W

1

and the cut paper web W

2

can travel smoothly.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.

Number	Name	Date
4452140	Isherwood et al.	Jun 1984
5361960	Fokos et al.	Nov 1994
5483893	Isaac et al.	Jan 1996
5927196	Murray	Jul 1999
6142074	Flament	Nov 2000

Paper web feed unit used in a rotary press and equipped with a paper web traveling tension controller

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (1)

US Referenced Citations (5)

Foreign Referenced Citations (1)