JPH0136609Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double-sided paper reversing device for double-sided printing in a sheet-fed printing press, which sucks the trailing edge of paper and grips and flips the trailing edge of the paper with a reversing claw.

With the diversification of printing, sheet-fed rotary printing presses equipped with various reversing devices that can be used for single-sided printing and double-sided printing have been proposed and put into practical use.
This type of printing press differs in the number and arrangement of cylinders, as well as the structure of the paper reversing device used for double-sided printing.
The paper reversing operation is the same in all cases. In other words, this type of printing press is equipped with a cylinder equipped with a non-reversing claw and a cylinder equipped with a reversing claw, with their peripheral surfaces facing each other, and in the case of single-sided printing, the reversing claw stops reversing. Then, the paper is replaced in the mouth in the same way as normal single-sided printing. In the case of double-sided printing, the phases of both cylinders are shifted in the circumferential direction by the length of the paper so that the trailing edge of the paper gripped by the claws of the upstream cylinder faces the reversing claws of the downstream cylinder. The end of the paper is caught in a reversing claw and conveyed as the cylinder rotates, thereby reversing the paper and printing on the back side with the next printing cylinder to perform double-sided printing.

In such a double-sided printing operation, when the trailing edge of the paper to be reversed faces the reversing claw, the trailing edge of the paper is separated from the reversing claw by the upstream cylinder side and cannot be held in the reversing claw. Since this is not possible, a suction device is often used that sucks the end of the paper toward the reverse claw side. This suction device is equipped with a suction head connected to an air source via a rotary valve, and the paper is suctioned by suctioning air through suction holes on the end face of this suction head. In a suction device, the suction head that has suctioned the paper rotates as the cylinder rotates, so that the paper is peeled off from the suction end surface, and the suction holes do not suck the paper, but allow outside air to pass through between the paper and the paper. The suction may cause the paper to be peeled off before it is held in the reversing claw, resulting in so-called paper drop, making it impossible to expect satisfactory paper delivery performance.

The present invention was developed in view of the above points, and the suction head is provided with a plurality of suction holes, and the diameter of the intake passage connecting each of these suction holes and the communication hole on the air source side is determined based on the paper tail of the suction paper. To provide a double-sided printing paper reversing device for a sheet-fed printing press, in which the diameter of the side on the gripping side is smaller than that on the side, so that the suction function can be maintained during the operation of holding the paper in the grip, thereby preventing paper from dropping. be. Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 7 show an embodiment of the double-sided paper reversing device according to the present invention, FIG. 1 is a cylinder arrangement diagram of a sheet-fed printing press in which this is implemented, and FIG. 2 is the driving side of the reversing cylinder. 3 is a side view of the operation side of the reversing cylinder, FIG. 4 is an enlarged cross-sectional view of the outer peripheral part of the reversing cylinder, and FIG. 5 is a partially broken plane showing the outer peripheral part of the driving side shaft end of the reversing cylinder developed. Fig. 6 is a partially cutaway plan view showing the outer periphery of the operation side shaft end of the reversing cylinder developed, and Fig. 7 is a partially cutaway plan view showing the outer periphery of the reversing cylinder showing the state in which the end of the paper is held in the double-sided printing corresponding to Fig. 4. FIG. In the figure, the first printing unit and the second printing unit of the printing press are
Plate cylinders 1 each having a printing plate attached to its circumferential surface
It is equipped with an inking device and a water supply device (not shown) that supply ink and water to the printing plate.Below the printing cylinder 1, a blanket cylinder 2 having the same diameter and onto which the image on the printing plate is transferred is installed. are placed facing each other.
Further, below each blanket cylinder 2, an impression cylinder 3 and an impression cylinder 4 having twice the diameter are arranged so that their circumferential surfaces are in contact with each blanket cylinder 2, and both impression cylinders 3 , 4 is provided with a reversing cylinder 5 having the same diameter as the reversing cylinder 5 with its circumferential surfaces facing each other. Reference numeral 6 denotes a swing device that swings using a cam mechanism, and is equipped with a swing claw that opens and closes using the cam mechanism. First impression cylinder 3
It is configured to supply The outer periphery of each double-diameter impression cylinder 3, 4 that rotates in the direction shown by arrow A in the figure is provided with a cam mechanism that opens and closes the swing pawl of a swing device 6 and a reversing pawl device 24 (described later) on the reversing cylinder 5. A plurality of sets of gripping claw devices 9 (hereinafter referred to as claws 9) each consisting of a claw and a claw base that alternately grip the paper 8 and wrap it around the circumferential surface of the trunk by rotation of the barrel are located at positions that divide the circumference into two. They are arranged in parallel at a predetermined interval on a pair of pawl shafts 10 that are mounted on a shaft. Number 1 in Figure 2
1 is an opening/closing cam that is fixed to the machine frame side and opens and closes the pawl 9, and the cam surface has a free end portion of the cam lever 12 that is fixed to the shaft end of the pawl shaft 10 by split tightening. The cam followers 13 of the two are in contact with each other.

Next, the configuration of the reversing cylinder 5 will be explained. The reversing cylinder 5 is rotatably supported by left and right frames 14 and 15 via tapered roller bearings 16, and rotates in the direction shown by arrow B in the figure, and two sets of paper holding and reversing devices are opposed to each other on its outer periphery. It is arranged as follows. Since these two sets have exactly the same configuration, only one of them will be explained. That is, the inversion trunk 5 is lightweight and integrally formed by a shaft core part, an outer peripheral part, and a plurality of skeletons connecting these parts, and disk-shaped pillows 17 and 18 are integrally provided at both ends. ing. In the left and right pillows 17 and 18, a pawl shaft 19 is regulated from moving in the axial direction by a collar 20 and is pivotally supported at both ends via a needle bearing 21. It is pivotally supported by a pawl bearing 23 fixed to the bottom of the trunk circumferential notch 2 . 24 indicates the impression cylinder 3,
A plurality of sets of reversing pawl devices are arranged in parallel on a pawl shaft 19 with different phases in the axial direction from the pawls 9 on the top of the screen, and the reversing pawls 25 shown in FIG. 8a and the pawl bases shown in FIG. 8b Accessories 2
It consists of 6. Of these, reversal claw 25
The pawl holder 29 is fixed to the pawl shaft 19 together with a spring receiver 27 with a bolt 28, and a pawl 31 is rotatably attached to an eccentric portion of the pawl holder 29 with a pivot 30. , the claw 31 has an adjustment screw 32 with a stepped portion in contact with the upper surface of the claw holder 29.
The claw 31 is screwed in through a letter-shaped anti-rotation washer 33, and the claw 31 is disposed between the claw holder 29 and the claw holder 29.
A toe spring 34 is attached to the toe spring 34 which biases the rotation force in the counterclockwise direction as shown in FIG. 8a. Also nail stand accessory 26
is formed of a nail rest holder 35 formed in a boat shape that encloses the reversing claw 25, and a nail rest 37 attached to its tip with a bolt 36 facing the claw 31. Between the other free end of the small item 26 and the spring receiver 27 of the reversing claw 25, there is a claw spring 3 that springs in the direction of closing the claw 31 and the claw base 37.
8 is interposed. Furthermore, a stopper stand 40 extending over the entire length of the body is fixed to a notch 39 provided in the trunk circumference near the tip of the reversing claw device 24 with bolts 41, and this stopper stand 40 has the following features:
A stopper 42 that restricts rotation of the reversing claw device 24 by abutting the bolt 36 of the claw base accessory 26 is screwed into each reversing claw device 24 with screws 43 and 44 to prevent loosening. . And reversal claw device 2
4 is constructed so that the entire body can be rotated approximately 250 degrees between the position shown in FIG. 4 and the position shown in FIG. 7 by means of a reversing drive device to be described later.

On the other hand, in the notch 22 of the reversing cylinder 5, a suction lever shaft 45 formed in the shape of a hollow tube is rotatably supported by the left and right pillows 17 and 18 via a needle bearing 46. A plurality of locations in the center thereof are supported by bearings 47 within the notch 22, and movement in the axial direction is restricted by a collar 48. Reference numeral 49 denotes a plurality of suction levers arranged in parallel on the suction lever shaft 45 in correspondence with the respective reversing claw devices 24, which are formed in an L-shape both in side view and plan view. It is fixed to the suction lever shaft 45 with a bolt 50.

FIG. 9 is a sectional view and a perspective view showing one free end of the suction lever 49, and a prismatic suction head 51 with an arcuate end face is attached to the free end. A pair of suction holes 51a and 51b are bored in the arcuate end surface of the reversing cylinder 5 in parallel along an arc curved in the circumferential direction.
Each of the suction holes 51a and 51b is connected to a communication hole 52 which passes through the suction head 51 and communicates with the inside of the suction lever shaft 45, through suction passages 51c and 51d, respectively. The diameter of the other intake passage 51d on the suction paper holding side is much smaller than the diameter of the intake passage 51c on the reversing claw device 24 side. In the middle of the communication hole 52,
A valve pin 53 for opening and closing the communication hole is provided and softly braked by a synthetic resin bolt 54. Further, on the other free end of the suction lever 51, a stopper 55, which is integrated with a spring receiver, a bolt, and a nut, and which restricts the rotation of the small pawl block 26, is attached in the protruding direction by a compression coil spring 56. It is mounted so that it can slide freely. Furthermore, a hollow suction lever shaft 4
5 has one end closed and the other end connected from the pillow 17 to the frame 1
This protruding part is rotatably fitted into the rotary valve 57 formed in an annular shape, and the circular arc-shaped hollow part formed in a part of the rotary valve 57 and the inside of the suction lever shaft 45 are connected to each other. are in communication. On the other hand, on the frame 14 side, there is a valve 58 formed in an annular shape so that the inner circumferential surface of the rotary valve 57 is in sliding contact with the outer circumferential surface of the bolt 5.
9, and an intake port 60 that communicates with the interior of the rotary valve 57 when facing the rotary valve 57 is installed at one location.
0 is fitted with a flexible tube 61 connected to an intake device attached to the machine base.

Next, a driving device for reversing and opening/closing the reversing claw device 24 and rotating the suction lever 49 will be described. On the downstream side in the rotational direction of the reversing cylinder 5 with respect to the pawl shaft 19, a reversing drive shaft 62 formed in a hollow tubular shape is rotatably mounted via a bush 63 and a needle bearing 64 in the thick portions of the pillows 17 and 18. The movement in the axial direction is restricted by a collar 65 and a segment gear 66, which will be described later. The segment gear 66 is fixed to the protruding part of the reversing drive shaft 62 from the pillow 17 with bolts 67, and the segment teeth at its free end mesh with the pinion 68 fixed to the protruding part of the pawl shaft 19. There is. A pin 69 is slidably supported in the center of the segment gear 66.
, there is a reversing cam 70 fixed to the frame 14 side.
A cam follower 71 facing the is fitted,
Move the pin 69 along the long hole 72 and remove the bolt 7.
3, the cam follower 71 moves as shown by a solid line and a chain line in FIG. . By doing this, when the reversing cylinder 5 rotates, the segment gear 66 swings due to the action of the cam surface of the reversing cam 70 and the cam follower 71, and the reversing claw device 24 rotates approximately 250 degrees at a predetermined timing as described above. and flip it. The reference numeral 74 in FIG. 5 is a scale plate that indicates the position of the cam follower 71. Furthermore, the reversing drive shaft 62
A pair of left and right spring levers 75 are located above the pillows 17 and 18.
A spring shaft 76 is split-fastened close to the inside of the spring lever 75, and one end of the spring shaft 76 is pivoted to the free end of the spring lever 75. The spring shaft 76 extends through the vicinity of the trunk core to the opposite trunk circumference, and has the other end connected to a bearing. It is slidably supported. A cam follower 71 is mounted on this spring shaft 76.
A compression coil spring 77 is attached to apply a rotational force to the segment gear 66 in the direction of pressing the segment gear 66 into contact with the cam surface of the reversing cam 70. Reference numeral 78 denotes a stopper fixed to the outer circumference of the pillow 17, which includes a pin 81 with a compression coil spring 80 slidably supported on the support plate 79, and an oval-shaped cam 8 attached to the tip of the pin 81.
2, and the pin 81 is connected to the compression coil spring 8.
By rotating the cam 82 by 90 degrees while pushing against the elastic force of 0 to change the engagement position of the notch 83, the cam 82
The large diameter part of the bolt 84 is the free end of the segment gear 66.
, the cam follower 71 is slightly separated from the cam surface of the reversing cam 70, and the cam follower 71
is configured to facilitate axial movement of the

A cam follower 86 is pivotally attached to a cam lever 85 that is fixed to a protruding portion of the claw shaft 19 from the pillow 18, and a gripping cam 87A is fixed to the frame 15 with a phase shift in the circumferential direction. ,
It is configured to come into contact with either the release cam 87B or the reverse gripping cam 88 at a predetermined timing. That is, the gripping cam 87A is the reversing claw device 2.
4 is not reversed and is in the state shown in FIG. When it is reversed and in the state shown in Figure 7, the first
The reversing claw 25 is used to change the grip of the paper 8 from the impression cylinder 3.
It is a cam that opens and closes the The release cam 87B is a cam that opens and closes the reversing claw 25 in order to transfer the paper 8 to the second impression cylinder 4. Further, a torsion bar 90 having a hexagonal head at one end fitted into a hexagonal hole 89 at the end of the shaft is passed through the inside of the reversing drive shaft 62, and a hexagonal head at the other end of the torsion bar 90 is inserted into the hexagonal hole 89 at the end of the shaft. It is fitted and fixed into a hexagonal hole 93 of a bearing plate 92 which is rotatably fixed to the side pillow 18 with a bolt 91. Reference numeral 94 is a pin for adjusting the scale for indicating the rotational position of the bearing plate 92. And the torsion bar 90 is the cam follower 71,8
6 is removed from any of the cams 70, 87A, 87B, and 88 and the rotation of the pawl shaft 19 is no longer restricted, the bearing plate 92 is torsionally adjusted so that elastic force is still accumulated. It is configured to urge the reversing claw 25 in the closing direction via the segment gear 66 and pinion 68.

Next, the reversing cylinder 5 relative to the suction lever shaft 45
On the upstream side in the rotational direction of the collar, a suction drive shaft 94 formed in the shape of a hollow tube is rotatably supported in the thick part of the pillows 17 and 18 via a bush 95 and a needle bearing 96. 97 and a segment gear 98 to be described later, movement in the axial direction is restricted. The segment gear 98 is fixed to the protruding part of the suction drive shaft 94 from the pillow 18 with bolts 99, and the segment teeth at its free end are connected to the pinion 100 fixed to the protruding part of the suction lever shaft 45.
It's meshing with each other. The other free end of the segment gear 98 has a cam follower 102 that is in contact with a suction lever rotation cam 101 fixed to the frame 15 side.
is fitted, and as the reversing cylinder 5 rotates, the segment gear 98 rotates due to the action of the suction lever rotation cam 101 and the cam follower 102, and the suction lever 4
9 is configured to rotate from the state shown in FIG. 4 to the state shown in FIG. 7 at a predetermined timing. Furthermore, a torsion bar 103 having a hexagonal head at one end fitted into a hexagonal hole at the end of the shaft is passed through the suction lever shaft 45, and the hexagonal head at the other end of this torsion bar 103 is inserted into the hexagonal hole at the other end of the torsion bar 103. Bearing plate 1 fixed to pillow 17 with bolts 104 so as to be rotatably adjustable
It is fitted and fixed into the hexagonal hole 106 of 05. 10
7 is a pin for adjusting the scale for indicating the rotational position of the bearing plate 105. The torsion bar 103 applies a rotational force to the segment gear 98 in the direction of pressing the cam follower 102 against the cam surface of the suction lever rotation cam. Further, the segment gear 98 has a stopper 108 on the outer periphery of the pillow 18 that restricts the rotation of the segment gear 98 in the counterclockwise direction in FIG. It is fixed and attached to. The stopper 108 has the same structure as the stopper 78, so each part is given the same reference numeral and the explanation thereof will be omitted.
The lift of the stopper 78 is much larger than that of the stopper 78, and is configured to move the cam follower 102 by a large amount.

The single-sided printing operation by the sheet-fed rotary printing press with a reversing mechanism configured as described above will be explained based on the above-mentioned figures and the operation explanatory diagram of FIG. 10. When switching from double-sided printing to single-sided printing, first rotate the cam 82 of the stopper 108 as shown by the chain line in FIG. It is regulated to prevent rotation from this state. As a result, the suction lever 49 is fixed so as not to move in the state shown in FIG. Next, by rotating the cam 82 of the stopper 78 and pushing the bolt 84 of the segment gear 66, the cam follower 71 is slightly separated from the reversing cam 70 to release the pressure applied by the spring, and then the cam follower 71 is rotated together with the pin 69. direction to escape from the reversing cam 70, and the stopper 78 is returned to its original state. By doing this, the reversing drive shaft 62 is attached to the pawl shaft 19 in FIG.
The elastic force of the torsion bar 90 inside acts through the segment gear 66 and pinion 68 to apply a rotational force in the counterclockwise direction in the figure. Since the rotation is restricted by the stopper 56 on the suction lever 49 side, the pawl 31 is pressed against the pawl base 37 by the rotational force of the pawl shaft 19 and the elastic force of the pawl spring 38, and is in the closed state. There is. In this state, the rotation of the claw shaft 19, that is, the opening and closing of the claw 31, is not driven from the segment gear 66 side, and the gripping cam 8
It operates in the same way as a general single-sided printing press, except that it is driven only from the release cam 7A and release cam 87B sides, and the shape of the nail rest is different. Note that since the suction lever 49 is not used, the intake device and the like connected to it are stopped. After preparing in this manner, when printing is started, the sheets of paper 8 are fed one by one onto the differential plate 7, pass through the swing device 6, are gripped by the claws 9 of the impression cylinder 3, and are wound around the impression cylinder 3. When passing between the rubber cylinder 2 and the blanket cylinder 2, printing is applied to the surface on the blanket cylinder 2 side. When each cylinder further rotates and the claw 9 of the impression cylinder 3 and the reversing claw device 24 of the reversing cylinder 5 face each other, the cam follower 86 comes into contact with the large diameter portion of the gripping cam 87A, so that the cam lever 85 is moved to the torsion bar 9.
After the claw 31 opens by swinging against the elastic force of 0, the claw 31 closes due to the elastic force of the torsion bar 90 after passing the large diameter portion. Since the pawl 9 on the impression cylinder 3 side opens and closes simultaneously with the opening and closing of the pawl 31, the paper 8 is transferred from the pawl 9 to the pawl 31 and wound around its circumferential surface by the rotation of the reversing cylinder 5. When the reversing pawl device 24 and the pawl 9 of the second impression cylinder 4 face each other, the cam follower 86 passes through the large diameter part of the release cam 87B and the pawl 31 opens and closes, and at the same time the pawl 9 opens and closes, so that the paper 8 is It is held in the second impression cylinder 4 and wound around its circumferential surface. Then, when the paper 8 passes between the blanket cylinder 2, printing is applied to the same side as the first color, and single-sided printing is performed.

Next, the double-sided printing operation will be explained based on the figures up to FIG. 9, the operation explanatory diagram of FIG. 11, and the suction operation explanatory diagram of FIG. 12. When switching from single-sided printing to double-sided printing, the reversing claw 25 of the reversing cylinder 5, which held the leading edge of the paper 8 during single-sided printing, grips the tail end of the paper, and the relative position with the claw 9 of the impression cylinder 3 changes. It is necessary to change the phase of each cylinder on the downstream side including the reversing cylinder 5 and each cylinder on the upstream side including the first impression cylinder 3 according to the size of the paper 8. The adjustment device allows the paper to be shifted by approximately the paper size. Further, the paper release timing of the cam that opens and closes the pawl 9 of the first impression cylinder 3 is delayed by approximately the same amount as the paper size. Then, the cam follower 71 for the reversing cam 70 is moved in the axial direction so as to come into contact with the reversing cam 70, and the segment gear 9 is moved by the stopper 108.
When the rotation restriction of 8 is released, the claw shaft 19 is moved to the reversing cam 70.
The suction lever 49 becomes rotatable by being driven from both the side, the gripping cam 87A, the releasing cam 87B, and the reversing gripping cam 88 side.
When printing is started after making preparations in this way, the paper, which has been printed on the side on the side of the blanket cylinder 2, is held in the claw 9 between the blanket cylinder 2 and the first impression cylinder 3, as in single-sided printing. 8, after being released from the grip of both trunks 2 and 3, the first
As shown in FIG. 1a, the paper is wound around the impression cylinder 3 until the trailing edge of the paper comes into contact with the reversing cylinder 5. When the cam follower 102 of the segment gear 98 reaches the large diameter part of the suction lever rotating cam 101 a little before this, the segment gear 98 rotates against the elastic force of the torsion bar 103 and attracts the suction lever via the pinion 100. The lever 49 is rotated to the position shown in FIG. 7 so as to escape from the claw base holder 35. Also, a moment later than this, the cam follower 71 of the segment gear 66 reaches the large diameter part of the reversing cam 70, and the segment gear 66
is rotated, and the pawl shaft 19 is largely rotated via the pinion 68, so that the entire reversing pawl device 24 is largely rotated to the position shown in FIG. At this time, the reversing claw 25
is closed. The suction lever 49 is attached to the claw stand holder 35
When it has finished dodging and no longer interferes with it, it returns to the position shown in Figure 4.

After the above operations are instantaneously performed, when the reversing claw device 24 and the suction lever 49 face the end of the paper as described above, the hollow part of the rotary valve 57 faces the intake port 60 of the valve 58. Since air is taken in, the intake hole 5 passes through the inside of the suction lever shaft 45, the communication hole 52, and the intake passages 51c and 51d.
Since outside air is sucked in from 1a and 51b, the tail of the paper 8 is attracted to the arc-shaped end surface of the suction head 51. From now on, each cylinder rotates approximately 30 degrees, and while the suction lever shaft 45 rotates as shown in the trajectory shown in FIG. 12, the suction lever 49 returns to the position shown in FIG. 7 while still suctioning the paper 8. It rotates and occupies the position shown in solid line in FIG. At this time, due to the rotation of the pawl shaft 19, the cam lever 85 attached to the other shaft end also rotates greatly, and the cam follower 85 is rotated as shown in FIG.
is opposed to the reversing gripping cam 88, the reversing cam 70 is removed, and the claw shaft 19 is facing the cam follower 86.
passes through the large diameter portion of the reversing gripping cam 88, thereby reciprocatingly rotates and the reversing claw 25 opens and closes. That is, when the reversing claw 25 is opened, the suction lever 49 that has sucked the tail of the paper rotates and brings the tail of the paper into its gripping position, and the reversing claw 25 closes, so that the tail of the paper is caught by the reversing claw 25. . As shown in FIG. 12, from when the tail of the paper is suctioned until it is gripped by the reversing claw 25, the paper 8, which was initially suctioned and extending tangentially to the suction surface of the suction head 51,
However, the paper 8 is gradually pulled in a direction such that it is peeled off from the suction surface, and a gap is created between the suction hole 51b side and the paper 8, which often attracts outside air. However, in this device, the suction hole 51b
By reducing the diameter of the side intake passage 51d,
Even if a part of the paper 8 is peeled off and outside air is sucked through the suction hole 51b, the air resistance is large and the air flow is poor.
It is concentrated on the 1a side, and the paper trailing edge is not strongly attracted and peeled off from the suction surface.

In this way, at the same time as the reverse pawl 25 grips the trailing edge of the paper, the pawl 9 of the first impression cylinder 3 opens and closes to release the paper 8 from its grip, and the suction air to the suction lever 49 is cut off. Then, as each torso rotates further,
The reversing gripping cam 88 disappears, and the reversing claw 25 rotates together with the reversing cylinder 5 while holding the tail end of the paper to transport the paper 8 as shown in FIG. The reversing claw device 24 as a whole returns to the posture shown in FIG. 4 due to the elastic force of the compression coil spring 77 and the torsion bar 90. As a result of the paper tail being conveyed in this manner, the paper 8 is reversed and wound around the reversal cylinder 5 so that the printed surface comes into contact with the circumferential surface of the reversal cylinder 5. When the reversing claw device 24 and the suction lever 49 have finished rotating, it is exactly the same as in the case of single-sided printing, and the reversing claw 25 opens and closes under the action of the release cam 87B, and the second
The claw 9 of the impression cylinder 4 opens and closes to change the grip on the paper 8, and then the paper 8 is wrapped around the impression cylinder 4.
When passing between the two, printing is applied to the back side, resulting in double-sided printing.

In this embodiment, the reversing cylinder is provided with a reversing claw device and a suction device, and this reversing cylinder is installed between the front and rear impression cylinders. There are no limitations on the arrangement, the structure of the reversing claw device, the structure of the drive mechanism of the suction device, etc.

As is clear from the above explanation, according to the present invention, a plurality of suction holes of a suction head are provided in a double-sided printing paper reversing device of a sheet-fed printing press, and an air intake connecting these suction holes and an air source side communication hole is provided. By making the diameter of the path on the side of the suction paper smaller than that on the side of the paper tail, the tail of the reversed paper adsorbed on the suction surface of the suction head is peeled off from the side of the suction head, and the path is placed in the mouth. Even if outside air is sucked in through the intake hole on the side of the paper, the air resistance of the small-diameter intake path prevents a large amount of outside air from being sucked in from this intake hole, and the suction force is concentrated on the intake hole on the edge of the paper. Since the paper continues to be strongly sucked, the paper to be reversed is not peeled off from the suction surface, and paper drop-off is prevented, the paper reversal function is significantly improved, and the occurrence of paper waste can be reduced.

[Brief explanation of the drawing]

1 to 12 show an embodiment of the double-sided paper reversing device for a sheet-fed printing press according to the present invention, and FIG. 1 is a cylinder arrangement diagram of a sheet-fed rotary printing press in which this is implemented, and FIG. Similarly, Fig. 3 is a side view of the driving side of the reversing cylinder, Fig. 3 is a side view of the operating side of the reversing cylinder, Fig. 4 is an enlarged sectional view of the outer periphery of the reversing cylinder, and Fig. 5 is an expanded view of the outer periphery of the shaft end of the reversing cylinder on the driving side. FIG. 6 is a partially cutaway plan view showing the outer periphery of the operating side shaft end of the reversing cylinder developed, and FIG. An enlarged cross-sectional view of the outer peripheral part of the reversing cylinder shown in FIG.
8b is a side view of the reversing claw, FIG. 8b is a side view of the small claw base, FIG. 9a is a sectional view of the suction head, FIG. 9b is a perspective view of the suction head, and FIG. 10 is an explanation of the operation of single-sided printing. 11 is an explanatory diagram of the double-sided printing operation, and FIG. 12 is an explanatory diagram of the suction operation. 3...Impression cylinder, 8...Paper, 25...Reversing claw, 49
...Suction lever, 51...Suction head, 51a,
51b...Adsorption hole, 51c, 51d...Intake path, 52...Communication hole.

Claims (1)

[Scope of utility model registration request] In a reversing device for double-sided printing of a sheet-fed printing press, in which the trailing edge of paper wrapped around an upstream cylinder is adsorbed by a suction device on a downstream cylinder that is in contact with the cylinder, and the paper is reversed by being gripped by a reversing claw. , a plurality of suction holes are formed in the end surface of the suction head provided in the suction device, and the diameter of the suction path connecting the suction holes located on the paper holding side and the air source side communication hole is set; A double-sided paper reversing device for a sheet-fed printing press, characterized in that the diameter is smaller than the diameter of an air intake path that connects the air intake hole located on the trailing edge side of the paper and the communication hole.