JP2008207892A - Sheet-fed printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet-fed printer capable of conveying/treating sheet at stable attitude, capable of double-side printing and one-side printing. <P>SOLUTION: The sheet-fed double-side printer 1 is provided with a gripper 35 for gripping the printed sheet 9 and moved while passing through a sheet conveying route S; and a sheet guide device 29 having a guide route part K arranged below the sheet conveying route S and arranged approximately parallel to the sheet conveying route S and having an endless belt 57 having wider width than the maximum width of the sheet 9 circulated/driven so as to be moved in the same direction as the gripper 35 at the approximately same speed in the guide route part K. On the sheet guide device 29, an opening part 75 provided on at least one position on a midway of the guide route part K and forming a non-continuous portion of the endless belt 57 and a suction part 59 arranged on the opening part 75 so as to be positioned below the guide route part K and applying suction force having adjustable magnitude to the sheet conveying route S side are provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sheet-fed printing machine, and more particularly to a sheet-fed printing machine that combines both double-sided printing and single-sided printing.

In a paper discharge device of a sheet-fed printing press, a printed sheet is conveyed with its leading end held by a gripper in a state where the printing surface is not sufficiently dried, and therefore the whole tends to be greatly undulated as it travels.
This waving may cause the sheet to come into contact with the surrounding members and be rubbed, resulting in scratches or smudges on the sheet or its printed surface. In particular, this prevention is important in double-sided printing that is also printed on the lower surface.
On the other hand, especially in single-sided printing, the tendency of the sheet to stick to the blanket cylinder due to the viscosity of the ink is concentrated on one side and overlaps multiple times, so the sheet tends to bend (curl) to one side. Is strong. For this reason, there is a type in which a decurler for removing the curl by sucking the free end side of the conveyed sheet is provided in the sheet conveyance path.

Various devices have been proposed for conveying a sheet in a stable posture and preventing the sheet from being damaged or soiled. These guides guide the sheet by arranging the guide substantially parallel to the sheet conveyance path, and are roughly classified into those that prevent the sheet from contacting the guide and those that contact the guide.
The former is simply provided with a fixed guide so that the air layer between the sheets does not contact the guide, or air is flowed over the surface of the guide to attract the sheet to the guide by the Bernoulli effect and There are some that float the sheet by the air layer and move it along the guide, such as an air layer that suppresses contact of the sheet with the guide.
In the latter, a belt that moves at substantially the same speed as the sheet along the sheet conveyance path is used as a guide, and the sheet is brought into contact with this belt (because the belt and the sheet are at substantially the same speed, they do not rub against each other). ) Information.

As what performs the latter method, what is shown by patent document 1 and patent document 2, for example is proposed.
Patent Document 1 uses a perforated belt that moves at substantially the same speed as the sheet, and acts on the sheet through the belt hole by the suction force provided by the suction means provided on the back of the belt substantially the entire length of the conveyance area. The sheet is conveyed by holding the sheet on the belt.
In Patent Document 2, a belt having a width wider than two sheets moving at the same speed as a sheet with a space along a sheet conveyance path is disposed, and a decurler is selectively disposed between the two belts. It is supposed to be located. Also shown is a belt divided into a plurality of parts in the width direction. In this case, a belt is installed on the lower surface of the belt, air is passed over the surface, and the sheet is sucked into the belt. Also shown in contact with.

Japanese Patent Laid-Open No. 6-211402 Japanese Patent Laid-Open No. 4-211943

However, the technique disclosed in Patent Document 1 requires a large suction means, and there is a problem that there is no room for a decurler and it cannot be used for single-sided printing.
Further, in the case of double-sided printing that does not use a decurler, the one disclosed in Patent Document 2 does not attract the sheet to the belt side, and thus disturbances in the sheet conveyance state occur, for example, centrifugal force acting on the curved portion, etc. There is a problem that the sheet may flutter and contact the belt irregularly, the sheet may rub, and scratches or dirt may occur.
When the belt is divided into a plurality of parts in the width direction, the sheet is sucked, so this problem does not occur except for the interval between the belts. However, since the sheet is sucked and contacts a plurality of belts in the width direction, it is rubbed at the corners of both ends of each belt, and there is a possibility that the sheet may be scratched or soiled. In a sheet-fed printing press that processes a sheet having a size, since the influence on the sheet is different between the guide in which air is jetted on the guide surface and the plate-like guide, the behavior of the sheet changes. The change of the behavior causes the sheet to wave, so that the sheet may hit the plate-shaped guide or the like to cause scratches or dirt.

  The present invention has been made in view of such circumstances, and provides a sheet-fed printing machine capable of transporting and processing a sheet in a stable posture corresponding to double-sided printing and single-sided printing. With the goal.

In order to solve the above problems, the present invention employs the following means.
That is, the sheet-fed printing press according to the present invention is provided with a gripper that moves through a sheet conveyance path in response to a printed sheet, and is disposed below the sheet conveyance path and substantially parallel to the sheet conveyance path. A guide device having a belt member wider than the maximum width of the sheet that is driven to circulate so as to move at the same speed in the same direction as the gripper in the guide route portion. A sheet-fed printing press provided with at least one location in the middle of the guide path portion in the guide device, the discontinuous portion where the belt member is discontinuous, and the guide path portion in the discontinuous portion And a suction portion that is arranged so as to be positioned below and applies a suction force whose size can be adjusted to the sheet conveyance path side.

By gripping the leading end by the gripper, the sheet conveyed through the sheet conveying path moves with the trailing end hanging downward. Since the belt member that is driven to rotate at substantially the same speed as the gripper travels on the guide path portion that is disposed substantially in parallel below the sheet conveyance path, the rear end portion of the sheet is in contact with the belt member. Moves with it in state. In other words, the sheet moves while being guided by the belt member.
When the sheet reaches the discontinuous portion, the sheet is pulled by the suction force by the suction portion and moved to the belt side. In this way, since the suction portion pulls the sheet toward the belt, it is possible to effectively suppress the sheet from floating from the belt even when a disturbance such as separation from the belt acts on the sheet.
As described above, since the sheet is prevented from being lifted by the suction portion, it is possible to prevent the sheet from flapping and coming into contact with the belt member or the like by being lifted, thereby preventing the occurrence of scratches, dirt, and the like, thereby preventing deterioration in print quality. be able to.

At this time, when processing a sheet printed on both sides, the printed surface may be damaged if it comes into contact with a non-moving suction part, so that the suction force of the suction part is in contact with the suction part. It is adjusted in the range below the size of not to do.
In addition, if the sheet is pulled so as to be close to the suction part, rubbing may occur between the belt member at both ends of the discontinuous part and the sheet. It is preferable to set the size so as to be able to counter the force to lift.
Therefore, a suction portion is installed in a portion where a large force to lift the sheet in the sheet conveyance path is applied, for example, a curved portion where a centrifugal force acts in the direction in which the sheet is lifted, and the suction force It is preferable to increase the value.
When there are many locations where such a force (disturbance) that lifts the sheet acts, suction portions may be provided at a plurality of locations as necessary.

On the other hand, when processing a sheet printed on one side and performing curl removal, the suction force of the suction unit is increased.
When the suction force of the suction part is increased, the sheet is pulled greatly by the suction part and moves downward. Therefore, the sheet is formed in a convex shape where it contacts the belt member on both sides of the discontinuous part, and is lowered downward by the suction part. It is a convex shape.
As the sheet advances, the position in this state sequentially moves to the rear end side, so that the sheet is squeezed up and down. When squeezed in this way, the curl (generally an upwardly convex curve) generated in printing can be deformed in the reverse direction to correct the curl.

In this way, by adjusting the suction force of the suction portion, the sheet can be conveyed in a stable posture by preventing the sheet from lifting, or the curvature (curl) of the sheet can be corrected. Both types of single-sided printing can be easily handled.
Since the belt member wider than the maximum width of the sheet is used, the surface where the sheet contacts the belt member is a flat plane. For this reason, since the contact state in the width direction of the sheet is constant, printing troubles such as back dirt, scratches, and scratches can be further suppressed.

Moreover, in the said invention, it is suitable for the said attraction | suction part to adjust the magnitude | size of the said attraction | suction force by making it contact / separate with respect to the said guidance path | route.
If it does in this way, if a suction part approaches a guidance course, suction power will become large, and if it separates, suction power can be made small.
Moreover, in the said invention, it is suitable for the said suction part that the magnitude | size of the said suction force is adjusted by adjusting the magnitude | size of the space | interval of the said discontinuous part in the upper direction.
If the interval between the discontinuous portions above the suction portion is reduced, the resistance to the air passing through this portion increases, so the suction force decreases. On the contrary, when the interval between the continuous portions is increased, the resistance to the air passing therethrough is reduced, so that the suction force can be increased.

  In the sheet-fed printing press according to the present invention, the belt member is detoured so as to pass under the suction portion at the discontinuous portion.

Thus, since the belt member is detoured so as to pass below the suction portion at the discontinuous portion, the guide path portion can be constituted by a single belt member.
As described above, when the belt member is constituted by a single belt member, the belt member driving device and the cleaning device for cleaning the surface of the belt member may be each one, so that it can be manufactured at low cost.
Further, since it is a single drive device, the speed can be easily synchronized and the operability can be improved as compared with a device that operates with a plurality of units.
Furthermore, although the surface cleaning of the belt member is performed relatively frequently, since it is a single cleaning device, its workability can be improved as compared with a device provided with a plurality of cleaning devices.

  In the sheet-fed printing press according to the present invention, the belt member is divided at the discontinuous portion and is driven separately.

Thus, since the belt member is divided at the discontinuous portions and driven separately, the length of one belt member can be shortened.
For this reason, since the length of each belt member is shortened, maintenance work such as replacement of the belt member can be easily performed, and when applying tension to the belt member, the amount of extension of the belt member can be reduced, The adjusting means can be reduced in size.

  In the sheet-fed printing press according to the present invention, the sheet conveyance path and the guide path include a curved portion that is curved upward and the suction portion is at least the curved portion of the guide path or the vicinity thereof. Is provided.

Since the upward centrifugal force acts on the passing sheet in the upwardly curved curved portion existing in the sheet conveyance path and the guide path, the sheet tends to move upward away from the belt member.
In the present invention, since the suction portion is provided at least in the curved portion of the guide path or in the vicinity thereof, the suction portion sucks the sheet which is about to move away from the belt member and the belt member Can be prevented from floating.
Accordingly, it is possible to prevent the sheet from fluttering and coming into contact with the belt member or the like to cause scratches, dirt, and the like, and to prevent deterioration in print quality.

According to the present invention, the guide device is provided in at least one position in the middle of the guide path portion, and the belt member is discontinuous, and the discontinuous portion is positioned below the guide path portion. And a suction part having a suction part that applies a suction force that can be adjusted in size on the side of the sheet conveyance path, so that the lift of the sheet is prevented by adjusting the suction force of the suction part. Thus, the sheet can be conveyed in a stable posture, or the curvature (curl) of the sheet can be corrected. Therefore, both double-sided printing and single-sided printing can be easily handled.
As a result, the sheet is prevented from being lifted by the suction part, so that the sheet can be prevented from fluttering and coming into contact with the belt member or the like due to the sheet floating, thereby preventing the occurrence of scratches, dirt, etc., and preventing deterioration in print quality. Can do.
Further, when the suction force of the suction part is increased, the curl generated by printing can be deformed in the reverse direction to correct the curl.

Embodiments according to the present invention will be described below with reference to the drawings.
[First embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a front view showing an overall schematic configuration of a sheet-fed duplex printing machine (sheet-fed printing machine) 1.
The sheet-fed duplex printing machine 1 realizes color printing by printing different colors, for example, with the sheet feeding device 3 that supplies the stacked sheets from the upstream side to the downstream side to which the sheet to be printed is supplied A plurality of printing units 5 and a paper discharge device 7 for placing printed sheets in a stacked state.

The sheet feeding device 3 picks up and supplies the sheets 9 stacked on the sheet feeding table 11 one by one from the top by a sheet feeding mechanism (paper suction, cam, etc.) not shown.
The paper feed tray 11 is configured to move up in response to the supply of the sheet 9 so that the paper feed mechanism maintains a substantially constant positional relationship with the sheet 9.

A plurality of printing units 5 are provided for each color to be printed. In the present embodiment, a four-color machine that prints with four colors consisting of C (cyan), M (magenta), Y (yellow), and BL (black) is shown, and printing is performed on both the front and back sides of the substrate. Therefore, a total of eight printing units 5 (printing unit 5a for front side printing and printing unit 5b for back side printing: hereinafter, when not distinguishing between front side printing and back side printing, the suffix is omitted) Is provided.
Four printing units 5b for printing the back surface (lower surface) of the sheet 9 in the first half and four printing units 5a for printing the front surface (upper surface) of the sheet 9 in the second half are arranged so as to be continuous. Between these groups of printing units 5, a connecting unit 6 that adjusts the printing surface on the sheet 9 is provided.

  Each printing unit 5 includes an inking device 13 for supplying ink, a dampening device 15 for supplying dampening water, a plate cylinder 17 disposed opposite to the inking device 13 and the dampening device 15, and this printing cylinder. 17 is provided with a blanket cylinder 19 disposed opposite to the pressure cylinder 17, an impression cylinder 21 disposed opposite to the blanket cylinder 19, and an intermediate cylinder 23 disposed between the impression cylinders 21 of the printing units 5.

The inking device 13 includes a plurality of ink rollers, and sequentially supplies ink from the ink fountain where ink is stored to the plate cylinder 17 side.
The dampening device 15 includes a plurality of rollers, and supplies dampening water stored in the water boat to the plate cylinder 17 side.
The inking device 13 and the dampening device 15 are configured to be separated from the plate cylinder 17 when printing is not performed or the like.

The plate cylinder 17 has a cylindrical shape in which a printing plate on which a printing image is formed is wound around the outer periphery. A printing plate is created and exchanged for each image to be printed.
Here, although not shown, the plate cylinder 17 is in a state where a part of the angular range of the outer periphery is notched in the axial direction, and at this position, the plate head and the printing plate which are the upstream end of the printing plate. A plate clamping device is provided for holding and fixing the plate bottom, which is the downstream end of the plate.

The blanket cylinder 19 receives the ink on the printing plate of the plate cylinder 17 and transfers the ink to the sheet 9 passing between the impression cylinder 21 (offset printing). A blanket made of an elastic material such as rubber is wound around the outer periphery of the blanket cylinder 19.
Here, although not shown, the blanket cylinder 19 is in a state where a part of the angular range of the outer periphery is cut out in the axial direction, and the upstream end and the downstream end of the blanket are grasped and fixed at this position. A pair of rubber-clad shafts is provided.
The blanket cylinder 19 is configured to be separated from the impression cylinder 21 and the plate cylinder 17 when printing is not performed or the like.

The impression cylinder 21 is disposed opposite to the blanket cylinder 19 and has a cylindrical shape. In addition, although the impression cylinder 21 in this embodiment is what is called double cylinder tailoring which has a diameter twice as large as the diameter of the plate cylinder 17 and the blanket cylinder 19, it is not restricted to this, The plate cylinder 17 and Even if a single cylinder type impression cylinder having the same diameter is employed, the present invention can be suitably implemented.
Here, claw devices (not shown) for holding the front end of the sheet 9 are provided at two locations on the peripheral surface of the impression cylinder 21 with the axis center in between.
The impression cylinder 21 contacts the blanket cylinder 19 through the sheet 9 during printing, and applies a desired pressure to the sheet 9 supplied between the impression cylinder 21 and the blanket cylinder 19. Thereby, the ink on the blanket cylinder 19 is transferred onto the sheet 9.

The intermediate cylinder 23 is provided between the impression cylinders 21 of the printing units 5 and has a cylindrical shape. In addition, although the intermediate | middle cylinder 23 in this embodiment is what is called a double cylinder tailoring which has a diameter twice as large as the diameter of the plate cylinder 17 and the blanket cylinder 19, it is not restricted to this, The impression cylinder mentioned above Similarly to the above, even if a single cylinder type intermediate cylinder having the same diameter as that of the plate cylinder 17 is employed, the present invention can be suitably implemented.
Here, claw devices (not shown) for holding the front end of the sheet 9 are provided at two locations on the peripheral surface of the intermediate cylinder 23 with the axis center in between. The sheet 9 is sent from the upstream impression cylinder 21 to the downstream impression cylinder 21 by the intermediate cylinder 23.

The inking device 13, dampening device 15, plate cylinder 17, blanket cylinder 19, impression cylinder 21 and intermediate cylinder 23 are provided on the sheet-fed double-sided printing machine 1 so that their peripheral speeds are substantially the same. It is rotated by a main motor (not shown).
That is, the rotational force from the main motor is transmitted to each member via the gear.

Next, the paper discharge device 7 will be described with reference to FIGS.
FIG. 2 is a front view illustrating a schematic configuration of the paper discharge device 7. FIG. 3 is an enlarged partial front view showing a part of the moving sheet guide portion.
The paper discharge device 7 includes a chain gripper 25 that conveys the sheet 9 while holding the leading end thereof, a paper discharge table 27 on which the sheets 9 are stacked, and a sheet guide device (guide device) 29 that guides the conveyed sheet 9. And a vacuum suction wheel 31 that brakes the sheet 9 traveling upstream of the paper discharge table 27.

The chain gripper 25 includes an endless chain 33 and a gripper 35.
A pair of endless chains 33 are installed on both sides of the paper discharge device 7, and each includes a paper discharge shaft 37 adjacent to the impression cylinder 21 and a driven shaft 39 installed above the downstream end of the paper discharge table 27. It is stretched between.
The endless chain 33 is guided by a guide member (not shown), passes below the paper discharge shaft 37, moves obliquely upward, moves substantially horizontally above the paper discharge table 27, and moves from the lower portion to the upper portion of the driven shaft 39. It is configured to be driven along a circuit path that moves around the upper position of the discharge shaft 37 by moving around the upper position of the discharge table 27 substantially horizontally, moving obliquely downward.

The gripper 35 is disposed so as to extend in the width direction (direction perpendicular to the paper surface in FIGS. 1 to 3), and both end portions are respectively held by the endless chains 33 on both sides.
A plurality of claw devices 41 (see FIG. 7) for holding or opening the sheet 9 by opening / closing operations are attached to the gripper 35 at intervals in the width direction.

The gripper 35 holds the sheet 9 at the position where the discharge shaft 37 and the impression cylinder 21 are engaged, holds the sheet 9 until it is released above the discharge table 27, and conveys the sheet 9 in the sheet conveyance direction SH.
In the case of the present embodiment, the position where the claw device 41 grips the sheet 9 is substantially the same as the movement trajectory of the endless chain 33, so that the movement trajectories of both are substantially the same. That is, of the movement trajectory of the endless chain 33, the movement trajectory of the endless chain 33 from the sheet 9 receiving position of the discharge shaft 37 to the position beyond the vacuum suction wheel is the sheet conveyance path S of the present invention.

In the sheet conveyance path S, a concave curved portion 49 that passes below the paper discharge shaft 37, a straight portion 51 that moves linearly obliquely upward from the exit of the paper discharge shaft 37, and a horizontal direction following the upper end of the straight portion 51 Further, there is a convex curved portion (curved portion) 53 that is convexly curved and a horizontal portion 55 that moves substantially horizontally following the convex curved portion (curved portion) 53.
The sheet guiding device 29 is provided below the sheet conveying path S, and guides the sheet 9 that is picked up and conveyed by the gripper 35 to the vacuum suction wheel 31.

The sheet guide device 29 includes a moving sheet guide unit 43, a fixed sheet guide unit 45, and a compressed air supply unit 47.
The moving sheet guide unit 43 guides the sheet 9 in a part of the horizontal part 55, the convex curved part 53, and the straight part 51.
The movable sheet guide unit 43 includes an endless belt (belt member) 57 and a suction unit 59.
The endless belt 57 is formed of an elastic material having heat resistance, for example, silicone rubber, fluorine rubber, or the like. The width of the endless belt 57 is larger than the width of the maximum sheet 9 to be printed.

The endless belt 57 has a moving path such that the endless belt 57 is driven around by a driving guide roller 61, a moving guide roller 63, an adjusting guide roller 65, a plurality of large diameter guide rollers 67, a plurality of small diameter guide rollers 69, and a fixed guide 71. Is formed.
Of the movement path of the endless belt 57, the side facing the sheet conveyance path S is formed by a drive guide roller 61, a guide roller 69, a fixed guide 71, and a movement guide roller 63 so as to be substantially parallel to the sheet conveyance path S. The guide route portion K of the present invention is configured. In this embodiment, the driving roller 61 is used for driving. However, the position of the driving roller is not limited to this, and another guide roller may be used as a driving roller, and a dedicated driving roller is provided. May be.

The drive guide roller 61 is installed so as to extend in the width direction at a substantially upstream end position of the linear portion 51, and is configured to be rotationally driven by a drive means (not shown).
The endless belt 57 is moved inwardly from the guide path portion K by the four guide rollers 69 at a substantially intermediate position of the straight portion 51 of the guide path portion K, an upstream position of the convex curve portion 53 and a downstream position of the convex curve portion 53. A concave movement path 73 is formed in which the cross section is recessed so as to form a substantially isosceles trapezoidal shape, in other words, detoured from the guide path portion K. An opening (discontinuous portion) 75 where the endless belt 57 does not exist is formed at a position along the guide path portion K of the concave moving path 73. The opening 75 extends in the width direction.
The concave movement path 73 and the opening 75 are provided at three locations. When these are distinguished, suffixes “a”, “b”, and “c” are added from the upstream side.

The fixed guide 71 is fixedly attached between the concave movement path 73b and the concave movement path 73c. The fixed guide 71 has a box shape and is formed so that the upper surface thereof follows the shape of the convex curved portion 53. Instead of the fixed guide 71, a plurality of driven rollers that form the rotation surface path of the endless belt 57 may be provided, and the convex curved portion 53 may be conveyed in such a manner that the virtual cross-sectional shape is a polygon.

The moving guide roller 63 is installed at the upstream side position of the vacuum suction wheel 31 so as to extend in the width direction. The movement guide roller 63 is attached such that the axis center is movable along the sheet conveyance direction SH. The moving guide roller 63 is moved approximately the same distance in the same direction as the moving amount of the vacuum suction wheel 31 accompanying the dimension change of the sheet 9 so that the distance from the vacuum suction wheel 31 is always kept substantially constant.
The moving guide roller 63 may be moved by using the driving means of the vacuum suction wheel 31 integrally with the vacuum suction wheel 31 or by using a separate and independent driving means.

The adjustment guide roller 65 is provided in a moving path from the moving guide roller 63 of the endless belt 57 toward the driving guide roller 61, and forms a moving path detouring in a direction crossing the moving path in cooperation with the pair of guide rollers 67. is doing.
The adjustment guide roller 65 is attached to be movable in this intersecting direction. The adjustment guide roller 65 adjusts the length of the detoured movement path by moving, thereby adjusting the tension of the endless belt 57 and adjusting the length of the guide path portion K accompanying the movement of the movement guide roller 63. It plays the function to do.

The suction part 59 is fixedly installed in a space surrounded by the concave movement path 73 and the opening 75.
In addition, the suction part 59 is provided in three places, and when distinguishing these, the suffix "a", "b", and "c" is attached from the upstream side.
The suction part 59 is a hollow isosceles trapezoidal column, and is arranged so that the longitudinal direction extends in the width direction. The suction part 59 is arranged such that a guide surface 77 that forms a short base of a trapezoidal cross section is substantially parallel to the guide path part K and located inside.

A slit 81 extending in the width direction is formed at a substantially intermediate position on a side surface (surface connecting both sides of the trapezoid) 79 of the suction portion 59. The slits 81 may be provided continuously in the width direction or may be provided separately.
A narrow space 83 is formed by the side surface 79 of the suction portion 59 and the endless belt 57. The slit 81 is configured to eject the compressed air introduced into the space diagonally downward with respect to the space 83.
Here, as an example of reducing the load of cleaning maintenance by human power, the present embodiment employs a structure provided with cleaning means 95 for cleaning the belt surface below the endless belt 57.

The fixed sheet guide 45 guides the sheet 9 in the concave curved portion 49.
The fixed sheet guide portion 45 has a hollow box shape, and is fixed below the paper discharge shaft 37 so as to be along the outer periphery thereof. The sheet discharge shaft 37 side of the fixed sheet guide 45 is constituted by a guide surface 85 formed so as to be substantially parallel to the sheet conveyance path S. The length in the width direction of the guide surface 85 is made larger than the width of the maximum sheet 9 to be printed.

Although not shown, the guide surface 85 has a plurality of air discharge nozzles that are capable of discharging compressed air toward both width ends with the central portion in the sheet conveying direction SH as a boundary. Installed. The air discharge nozzles are arranged in a plurality of rows at intervals in the sheet conveying direction SH.
In the present embodiment, the fixed sheet guiding portion 45 is configured by a single box-shaped structure, but it may be configured by a plurality of box-shaped structures separated in the sheet conveying direction SH.

The compressed air supply unit 47 includes a blower 87, a buffer tank 89, a supply pipe 91, and a regulating valve 93.
The blower 87 is a compressed air supply source, and a plurality of blowers 87 may be used as necessary. Moreover, you may make it use another means, for example, a compressor, as a supply source of compressed air.
The buffer tank 89 is a tank that temporarily stores the compressed air sent from the blower 87, and suppresses variations in the pressure and supply amount of the compressed air.
The suction part 59 is connected to the buffer tank 89 by a supply pipe 91.
The supply pipe 91 is provided with an adjustment valve 93 that adjusts the supply amount of compressed air.

The sheet-fed duplex printing machine 1 described as above operates as follows.
The sheets 9 stacked on the paper feed tray 11 of the paper feed device 3 are picked up one by one from the top by a paper feed mechanism (not shown) and supplied to the printing unit 5.
The supplied sheet 9 is picked up by the nail device of the intermediate drum 23 of the printing unit 5, and then changed from the intermediate drum 23 to the impression drum 21. This is repeated and conveyed through the connecting unit 6 and the eight printing units 5.

In each printing unit 5, water is supplied from the dampening device 15 to the non-image area of the printing plate attached to the peripheral surface of the plate cylinder 17, and then ink is supplied from the ink supply device 13 to the image area of the printing plate. Is done.
The printed image on the printing plate thus obtained is transferred to the blanket cylinder 19.
The printed image transferred to the blanket cylinder 19 is transferred to the sheet 9 conveyed by the impression cylinder 21, and printing of one color is performed.

When the sheet 9 passes between the blanket cylinder 19 and the impression cylinder 21 of the first four printing units 5b, four colors are printed on the back surface. Thereafter, when the sheet 9 printed on the back surface passes through the four printing units 5a located on the downstream side, printing of four colors is performed on the front surface. The sheet 9 on which double-sided printing is performed in this way is sent to the paper discharge device 7.
In the case of single-sided printing, in the printing unit 5b, the blanket cylinder 19 is separated from the impression cylinder 21, so that printing on the back surface is not performed, and printing is performed only on the front surface by the printing unit 5a.

The printed sheet 9 is changed over from the impression cylinder 21 of the last printing unit 5a to a gripper 35 that winds the paper discharge shaft 37.
The gripper 35 grips the leading end portion of the sheet 9, moves along the sheet conveyance path S, and is released by a paper release cam (not shown) when reaching the upper portion of the sheet discharge table 27 to release the grip of the sheet 9. .
The sheet 9 released from the gripper 35 falls downward while the speed in the traveling direction is suppressed (brake applied) by the vacuum suction wheel 31. The sheet 9 is brought into contact with the paper pad 32 to be positioned at the leading end, and is stacked on the sheets 9 stacked on the paper discharge table 27.

Next, the sheet 9 conveying operation in the paper discharge device 7 in single-sided printing or double-sided printing will be described with reference to FIG.
FIG. 7A is a schematic diagram showing a conveyance state of the sheet 9 printed on one side. FIG. 7B is a schematic diagram illustrating a conveyance state of the sheet 9 printed on both sides.
First, in the case of single-sided printing, in the printing unit 5a, the sheet 9 tends to stick to the blanket cylinder 19 due to the viscosity of the ink. That is, the rear end portion of the sheet 9 tries to go up. On the other hand, since the front end portion of the sheet 9 is gripped by the impression cylinder 21 and moves downward, the rear end portion is pulled by this and moves downward. For this reason, the rear end portion of the sheet tends to be curved so as to be convex upward. Since these are stacked by the four printing units 5a, they tend to bend, that is, curl so that the rear end portion of the sheet 9 is convex upward.
In the case of double-sided printing, the printing unit 5b is curved in the opposite direction, so both cancel out and curl is reduced.

In the sheet guide device 29, the drive guide roller 61 is operated, and the endless belt 57 moves along the movement locus at substantially the same speed as the endless chain 33. As a result, the endless belt 57 moves in the same direction as the endless chain 33 at substantially the same speed in the guide path portion K formed substantially parallel to the sheet conveying path S.
Then, the adjustment valve 93 is opened, and the compressed air whose pressure in the buffer tank 89 is adjusted is supplied to the internal space of the fixed sheet guide portion 45 and the internal spaces of the suction portions 59a, 59b, and 59c.
In addition, when there is a spatial restriction in the arrangement inside the apparatus, instead of the configuration in which the buffer tank 89 is provided, a structure in which piping is directly branched from the blower and the pressure is adjusted by an adjustment valve may be employed.

The compressed air supplied to the internal space of the fixed sheet guide 45 is ejected in the width direction along the guide surface 85 from the air discharge nozzle.
The compressed air supplied to the internal space of the suction part 59 is ejected downward along the side surface 79 from the slit 81.
At this time, for example, the regulating valve 93 provided in the supply pipe 91 that supplies the compressed air to the suction part 59a is largely released to increase the supply amount of the compressed air to be supplied. Thereby, the compressed air ejected from the slit 81 of the suction part 59a is ejected more strongly than that of the suction parts 59b and 59c.

In this state, when the sheet 9 is gripped by the gripper 35 and enters the concave curved portion 49, the top of the sheet 9 conveyed by the air flow caused by the air ejected from the air ejection nozzle of the fixed sheet guiding portion 45. Since a flow velocity difference (pressure difference) of air is generated on the lower surface, the static pressure of the guide surface 85 is reduced, and a suction force that causes the sheet 9 to follow the guide surface 85 is generated (Bernoulli effect). Be attracted to.
On the other hand, since the sheet 9 attracted to the guide surface 85 side is restrained from moving to the guide surface 85 by the air layer due to the air flow continuously ejected, the suction force by the Bernoulli effect and the restraining force by the air layer are reduced. At the balance position, the sheet 9 is conveyed in a stable posture with the trailing end portion hanging down.

When the sheet 9 maintains this posture and enters the straight portion 51 from the concave curved portion 49, the sheet 9 is conveyed in a state where the rear end portion of the sheet 9 is in contact with the endless belt 57.
In this state, the sheet 9 sequentially reaches the suction part 59a from the front end part.
In the suction part 59a, the compressed air is strongly jetted downward along the side surface 79 from the slit 81. Therefore, a large negative pressure is generated in the slit 81, and a large amount is formed between the upper part, for example, the air in the opening 75a. A pressure difference occurs.
Due to this pressure difference, the upper air moves downward, in other words, in the suction part 59a, the air in the opening 75a is pulled and moved by the pressure difference, so that a negative pressure is generated in the opening 75a and the passing sheet. A large pressure difference is generated in the air on the upper and lower surfaces of 9. When the sheet 9 reaches the suction part 59a due to this pressure difference, it is strongly attracted downward.

Since the sheet 9 is strongly attracted to the suction part 59a, the range in contact with the endless belt 57 is further increased. Further, since the rear end portion of the sheet 9 that is originally in contact is pulled in the direction of the suction portion 59a as shown in FIG. 7A by the strong suction force of the suction portion 59a, both end portions of the opening 75a. Is pressed against the endless belt 57 wound around the guide roller 69 to form a state along the curvature, that is, a convex shape upward. And in the space 83 part, it is pulled downward and becomes a downwardly convex shape.
As the sheet 9 advances, the position in this state sequentially moves to the rear end side, so that the sheet 9 is squeezed in the vertical direction.
Thus, curling caused by printing can be deformed in the reverse direction to correct the curl.

Further, the sheet 9 is conveyed and passes through the convex curved portion 53. At this time, since the convex curved portion 53 is convexly convex upward, a centrifugal force directed outward (upward) acts on the conveyed sheet 9. The seat 9 tends to leave the endless belt 57 by this centrifugal force.
When the sheet 9 passes through the opening 75 b that is the entrance portion of the convex curved portion 53, the sheet 9 is sucked by the suction portion 59 b in the same manner as the suction portion 59 a described above, and is pulled toward the endless belt 57. Will be allowed to.
Next, when the sheet 9 passes through the opening 75 c that is the exit portion of the convex curved portion 53, the seat 9 is sucked by the suction portion 59 c and pulled toward the endless belt 57.

The suction part 59b and the suction part 59c are arranged at intervals such that the suction force with respect to the conveyed sheet 9 acts continuously. When the length of the convex curved portion 53 in the sheet conveying direction is long and this state does not occur, one or more suction portions 59 are provided in the middle.
The suction portions 59b and 59c reduce the supply amount of compressed air by the adjustment valve 93 as compared with the suction portion 59a, and the suction force counters the centrifugal force applied to the seat 9 and the resistance of the air below the seat 9. It is to be about. Thereby, since the sheet 9 is not strongly pressed against the endless belt 57, the openings 75b and 75c are not damaged similarly to the opening 75a.

When the curling is corrected by the suction part 59b or the suction part 59c, the adjustment valve 93 may be opened to increase the supply amount of compressed air.
That is, by adjusting the suction force of the suction valve 59, any of the suction valves 59a, 59b, 59c can be decurled. If it cannot be removed at one place, it may be removed using a plurality of places.
Furthermore, since the sheet 9 passing through the straight portion 51 hangs downward due to its weight, it is easy to assume a posture in contact with the endless belt 57. For this reason, for example, if the above-mentioned curl removal can be performed in the suction portions 59b and 59c, the suction portion 59a may be omitted depending on the situation.

In this way, the sheet 9 in which the curl is removed by the suction portion 59a and the lifting at the convex curved portion 53 is suppressed by the suction portions 59b and 59c is endless in a stable posture in which the rear end portion is in contact with the endless belt 57. It moves with the belt 57.
In this way, curl peculiar to single-sided printing can be removed.
Further, even if a centrifugal force (disturbance) that moves away from the endless belt 57 acts on the seat 9, it is possible to effectively suppress the seat 9 from floating from the endless belt 57. As a result, it is possible to prevent problems such as the sheet 9 being bent, being lifted too much and contacting the upper structural parts such as a chain, causing damage to the surface of the sheet, or paper stacking being disturbed in the paper discharge unit. .

When the sheet 9 printed on one side is handled, since it is not printed on the back side, for example, if the surface of the endless belt 57 is formed of a material having a small friction coefficient, the endless belt 57 is not driven. However, it can be transported well.
An example of the material having a small friction coefficient is polytetrafluoroethylene, which forms the surface of the endless belt 57 (coating or the like).
Moreover, you may form with the nylon which adjusted the surface roughness smoothly.

Next, in the case of double-sided printing, the adjustment valve 93 of the suction part 59a is adjusted to reduce the supply amount of compressed air compared to single-sided printing, and the suction force counteracts the resistance of air on the lower side of the sheet 9. To be.
As a result, the sheet 9 passing through the opening 75a is sucked by the suction part 59a and pulled by the endless belt 57 as shown in FIG. 7B, but protrudes largely to the suction part 59a side by the opening 75a. Things will disappear. In this case, of course, the guide surface 77 is not contacted.

Accordingly, since the sheet 9 hardly wraps around the curvature portion of the guide roller 69, the speed difference between the endless belt 57 and the sheet 9 hardly occurs. For this reason, it can suppress that the sheet | seat 9 is damaged, a stain | pollution | contamination, etc. generate | occur | produce.
In the suction part 59b and the suction part 59c, as in the above-described single-sided printing, the suction force counteracts the centrifugal force applied to the sheet 9 and the resistance of air below the sheet 9. As a result, the sheet 9 is not strongly pressed against the endless belt 57, so there is no contact with the suction part 59 at the openings 75b and 75c, and no damage occurs.

In this way, the sheet 9 whose lifting at the convex curved portion 53 is suppressed by the suction portions 59a, 59b, and 59c moves together with the endless belt 57 in a stable posture in which the rear end portion contacts the endless belt 57.
Thus, since the suction portions 59a, 59b, and 59c pull the seat 9 toward the endless belt, it is effective that the seat 9 is lifted from the endless belt 57 even when a disturbance such as separation from the endless belt 57 acts on the seat 9. Can be suppressed.
Therefore, since the sheet 9 is prevented from being lifted by the suction portions 59a, 59b, 59c, the sheet 9 can be prevented from fluttering and coming into contact with the endless belt 57 and the like to be scratched and stained. Deterioration of print quality can be prevented.

  Further, since the suction force of the suction portions 59a, 59b, 59c is adjusted to a magnitude that can counter the expected force to lift the sheet, it is not strongly pressed against the endless belt 57. Scratches can be suppressed in the portions 75a, 75b, and 75c.

If such a printing operation is continued for a while, the surface of the endless belt 57 becomes dirty with ink or the like. Therefore, the cleaning means 95 is operated at an appropriate timing, for example, once every printing operation for one hour, and the surface of the endless belt 57 is Clean.
Thereby, possibility that the sheet | seat 9 will become dirty can be reduced further.
In addition, since the moving sheet guide portion is composed of one endless belt 57, the number of the cleaning means 95 may be one, and it can be manufactured at a low cost, and includes a plurality of cleaning means. Compared with this, the workability can be improved.

In this embodiment, the suction force of the suction unit 59 is performed by adjusting the amount of compressed air supplied by the adjustment valve 93. However, the suction force of the suction unit 59 is not limited to this and is appropriately determined. Means may be used.
For example, as shown in FIG. 5, the suction part 59 is attached to the guide path part K so as to be able to come into contact with and separate from the guide path part K, and the magnitude of the suction force is adjusted by moving the suction part 59 toward and away from the guide path part K. Good.
That is, when the suction part 59 approaches the guide path part K (see the two-dot chain line in FIG. 5), the suction force increases, and when it is separated (see the solid line in FIG. 5), the suction force decreases.

Further, as shown in FIG. 6, the pair of guide rollers 69 forming the opening 75 can be separated from each other, and the size of the suction force is adjusted by adjusting the distance between the openings 75. Also good.
That is, when the pair of guide rollers 69 are brought close to each other and the interval between the openings 75 is reduced (see the two-dot chain line in FIG. 6), the resistance to the air passing through this portion increases, so the suction force decreases. When the pair of guide rollers 69 are separated and the distance between the openings 75 is increased (see the solid line in FIG. 6), the resistance to the air passing therethrough is reduced, so that the suction force can be increased.

Further, in the present embodiment, the suction force in the suction part 59 is generated by ejecting the compressed air supplied from the blower 87 from the slit 81 provided on the side surface 79, but is not limited thereto. Any appropriate means may be used.
For example, a suction pump 99 may be used as shown in FIG. That is, in the suction portion 59, a slit 97 extending in the width direction is provided on the guide surface 77 instead of the slit 81 on the side surface 79.

The suction pump 99 is operated to make the cushion tank 101 have a negative pressure, and the negative pressure is applied to the hollow portion of the suction portion 59 via the supply pipe 91. The sheet 9 is sucked through the slit 97 by the negative pressure of the hollow portion.
The suction valve 59 adjusts the suction force of the suction part 59 by adjusting the magnitude of the negative pressure.
In addition, you may make it adjust a suction force as a structure like FIG. 5 and FIG.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS.
In this embodiment, the basic configuration is the same as that of the first embodiment, and the configurations of the printing unit 5 and the paper discharge device 7 are different. Therefore, in the present embodiment, this difference will be described, and redundant description of other parts will be omitted.
In addition, the same code | symbol is attached | subjected to the component same as 1st embodiment, and the detailed description is abbreviate | omitted.
FIG. 8 is a front view showing an overall schematic configuration of the sheet-fed duplex printing machine (sheet-fed printing machine) 1. FIG. 9 is a front view illustrating a schematic configuration of the paper discharge device 7.

In the present embodiment, the printing unit 5a for the front surface and the printing unit 5b for the back surface are alternately arranged by two units in this order from the upstream side.
The impression cylinders 21 of each printing unit 5 are connected by two intermediate cylinders 23 having the same diameter as the plate cylinder 17.
An intermediate cylinder 23 that conveys the sheet 9 from the impression cylinder 21 obliquely upward is interposed between the impression cylinder 21 of the most downstream printing unit 5 b and the paper discharge shaft 37.

In the present embodiment, the paper discharge shaft 37 of the paper discharge device 7 has substantially the same diameter as the driven shaft 39 and is installed at substantially the same height. However, the present invention is not limited to this. In the case of adopting the configuration in which the paper discharge shaft having the diameter is provided, a conveyance path corresponding to the path may be provided.
Specifically, as a configuration having substantially the same diameter, the sheet conveyance path S in the movement locus of the chain gripper 33 is formed to extend in the lateral direction (substantially horizontal direction).
The sheet guide device 29 includes a moving sheet guide unit 43 and a compressed air supply unit 47.
The movable sheet guide unit 43 guides the sheet 9 from the paper discharge shaft 37 to the vicinity of the vacuum suction wheel 31.
The constituent members of the moving sheet guide 43 are the same as those in the first embodiment. Of the movement path of the endless belt 57, the side facing the sheet conveyance path S is the drive guide roller 61, the guide roller 69, and the movement guide roller 63 so as to be substantially parallel to the sheet conveyance path S, that is, substantially horizontally. The formed guide route portion K is configured.
In this embodiment, the driving guide roller 61 is used for driving. However, the position of the driving roller is not limited to this, and another guide roller may be used as a driving roller, and a dedicated driving roller may be used. It may be provided.

The endless belt 57 is recessed from the guide path portion K so as to form a substantially isosceles trapezoidal shape inside by the four guide rollers 69 at a substantially intermediate position of the guide path portion K, in other words, the guide path portion K. A concave moving path 73 is formed that is detoured from.
An opening (discontinuous portion) 75 where the endless belt 57 does not exist is formed at a position along the guide path portion K of the concave moving path 73. The opening 75 extends in the width direction.
Similar to the first embodiment, the movement guide roller 63 is moved by substantially the same distance in the same direction as the movement amount of the vacuum suction wheel 31 when the size of the sheet 9 is changed. The adjustment guide roller 65 adjusts the tension of the endless belt 57 by moving, and adjusts the length of the guide path portion K accompanying the movement of the movement guide roller 63.
The suction part 59 has the same structure as that of the first embodiment, and is fixedly installed in a space surrounded by the concave movement path 73 and the opening part 75.

As described above, the sheet-fed duplex printing machine 1 according to the present embodiment operates as follows.
The sheets 9 supplied from the paper feeding device 3 to the printing unit 5 are sequentially changed by the nail devices of the intermediate cylinder 23 and the impression cylinder 21 and conveyed.
In the middle of the conveyance, the sheet 9 is printed on the surface when passing between the blanket cylinder 19 and the impression cylinder 21 of the first printing unit 5a. Next, when passing between the blanket cylinder 19 and the impression cylinder 21 of the printing unit 5b, printing is performed on the back surface. Then, when passing through the printing unit 5a and the printing unit 5b, printing is performed on the front surface and the back surface.

In this manner, the sheet 9 on which the two colors are printed on the front and back surfaces is sent to the paper discharge device 7.
In the case of single-sided printing, in the printing unit 5b, the blanket cylinder 19 is separated from the impression cylinder 21, so that printing on the back surface is not performed, and printing is performed only on the front surface by the printing unit 5a.
The double-side printed sheet 9 is transferred from the impression cylinder 21 of the last printing unit 5 b to the gripper 35 that winds the paper discharge shaft 37 through the intermediate cylinder 23 and is conveyed along the sheet conveyance path S.

Since the sheet 9 conveyed while being gripped by the gripper 35 moves in a state where the rear end portion hangs downward, a part of the sheet 9 moves while resting on the endless belt 57.
At this time, the amount of compressed air adjusted by the adjusting valve 93 is supplied from the buffer tank 89 to the suction unit 59. However, since there is only one suction part 59 as in this embodiment, the configuration may be such that the buffer tank 89 is omitted from the viewpoint of reducing the number of parts, and compressed air is directly supplied to the suction part 59 via an adjustment valve. .
When this compressed air is jetted downward along the side surface 79 from the slit 81, a negative pressure is generated in the portion of the slit 81, and a pressure difference is generated between, for example, the air in the opening 75.

Due to this pressure difference, the upper air moves downward. In other words, in the suction part 59, the air in the opening 75 is pulled downward and moves, so that a negative pressure is generated in the opening 75 and the sheet 9 passing therethrough is moved. A pressure difference occurs in the air on the upper and lower surfaces. This pressure difference causes the seat 9 to be pulled downward, that is, to the endless belt 57.
Since the sheet transport path S is substantially horizontal, there is little disturbance to try to lift the transported sheet 9. For this reason, in order to prevent the sheet 9 from coming into strong contact with the opening 75, the amount of compressed air supplied is adjusted to be small.

On the other hand, when the sheet 9 printed on one side is processed, the adjustment valve 93 is opened largely and the supply amount of the compressed air supplied to the suction unit 59 is adjusted to be increased.
Thereby, since the compressed air injected from the slit 81 of the suction part 59 is strongly injected, a large negative pressure is generated in the portion of the slit 81, and a large pressure difference with the air in the upper part, for example, the opening 75. Will occur.
Due to this pressure difference, a large pressure difference is generated in the air on the upper and lower surfaces of the passing sheet 9.

As a result, the sheet 9 is strongly attracted to the suction portion 59, and is thus pressed against the endless belt 57 wound around the guide roller 69 that forms both ends of the opening 75, and is in a state along its curvature, ie, upwardly projecting. Shape. And in the space 83 part, it is pulled downward and becomes a downwardly convex shape.
As the position of the sheet 9 advances, the position in this state sequentially moves to the rear end side, so that the sheet 9 is squeezed in the vertical direction.
Thus, curling can be corrected by deforming the curl generated in single-sided printing in the reverse direction.

  Thus, since the sheet 9 to be conveyed is forcibly attracted by the suction unit 59, even if a disturbance that lifts the sheet 9 occurs, the sheet 9 can be prevented from being lifted from the endless belt 57. It is possible to suppress the occurrence of scratches by fluttering and coming into contact with the endless belt 57 or the like. Further, when the amount of compressed air supplied to the suction unit 59 is increased to increase the suction force, the curl peculiar to the single-side printed sheet 9 can be removed.

In addition, when the length of the guide path part K is long, the suction part 59 may be provided at a plurality of places at intervals in the sheet conveyance direction SH.
Further, the suction structure shown in FIG. 4 may be used, or the structure shown in FIG. 5 or 6 may be used to adjust the suction force of the suction part 59.
Further, for example, if polytetrafluoroethylene is coated on the surface of the endless belt 57, when the sheet 9 printed on one side is handled, the endless belt 57 can be transported satisfactorily without being driven.

Further, in this embodiment, the movable sheet guide portion 43 is formed by a single endless belt 57, but as shown in FIG. 10, it is independently driven upstream and downstream of the suction portion 59. You may make it divide | segment into the upstream endless belt 103 and the downstream endless belt 105. FIG.
In this way, the upstream endless belt 103 and the downstream endless belt 105 are shorter in length than the endless belt 57, so that maintenance work such as replacement thereof can be easily performed. Further, when tension is applied to them, the amount of extension can be reduced, and the adjusting means can be reduced in size.

  Further, when the upstream endless belt 103 is driven slowly as compared with the downstream endless belt 105 or is driven slowly in the reverse direction, the squeezing force applied to the sheet 9 when the suction part 59 strongly sucks the sheet 9 is applied. Therefore, the curl removal effect of the sheet 9 printed on one side can be improved.

In each of the above-described embodiments, a four-color or two-color machine of a sheet-fed double-sided printing machine has been described as an example, but may be used for a sheet-fed printing machine such as a multi-color machine.
In addition, the present invention is not limited to the above-described embodiments, and can be appropriately changed without departing from the gist of the present invention.
For example, the trajectory of the sheet conveyance path S may have various shapes.

1 is a front view showing an overall schematic configuration of a sheet-fed double-sided printing press according to a first embodiment of the present invention. 1 is a front view illustrating a schematic configuration of a paper discharge device according to a first embodiment of the present invention. It is a front view which shows the suction part concerning 1st embodiment of this invention. It is a front view which shows another aspect of the attraction | suction part concerning 1st embodiment of this invention. It is a front view which shows another aspect of the attraction | suction part concerning 1st embodiment of this invention. It is a front view which shows another aspect of the attraction | suction part concerning 1st embodiment of this invention. It is a front view which shows operation | movement of the suction part concerning 1st embodiment of this invention. It is a front view which shows the whole schematic structure of the sheet | seat double-sided printing press concerning 2nd embodiment of this invention. It is a front view which shows schematic structure of the paper discharge apparatus concerning 2nd embodiment of this invention. It is a front view which shows another embodiment of the paper discharge apparatus concerning 2nd embodiment of this invention.

Explanation of symbols

1 sheet-fed double-sided printing machine 9 sheet 29 sheet guide device 35 gripper 53 convex curved part 57 endless belt 59 suction part 75 opening K guide path part S sheet conveyance path

Claims (6)

A gripper that picks up the printed sheet and moves through the sheet transport path;
The guide path portion is disposed below the sheet transport path and disposed substantially in parallel with the sheet transport path, and the guide path section is driven to rotate so as to move at the same speed in the same direction as the gripper. A sheet-fed printing press comprising a guide device having a belt member wider than the maximum width of the sheet,
In the guide device,
A discontinuous portion provided at least one place in the middle of the guide path portion, and the belt member is discontinuous;
A suction part that is arranged to be positioned below the guide path part in the discontinuous part, and that applies a suction force whose size can be adjusted to the sheet conveyance path side;
A sheet-fed printing machine comprising:   2. The sheet-fed printing press according to claim 1, wherein a magnitude of the suction force is adjusted by moving the suction unit toward and away from the guide path.   2. The sheet-fed printing press according to claim 1, wherein the suction unit adjusts the magnitude of the suction force by adjusting the size of the interval between the discontinuous parts above the suction unit.   4. The sheet-fed printing press according to claim 1, wherein the belt member is detoured so as to pass under the suction portion in the discontinuous portion. 5.   4. The sheet-fed printing press according to claim 1, wherein the belt member is divided at the discontinuous portion and driven separately. 5. The sheet conveying path and the guide path have a curved portion that is convexly convex upward, and the suction portion is provided at least in the curved portion of the guide path or in the vicinity thereof. A sheet-fed printing press according to any one of claims 1 to 5.

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