The present invention relates to a delivery device in a sheet-fed offset rotary printing press, which is arranged on the upstream sheet convey direction side of a pile board and comprises a suction unit for decreasing a sheet convey speed.
In a sheet-fed offset rotary printing press of this type, a sheet printed by a printing unit is conveyed as it is gripping-changed from the grippers of an impression cylinder to the grippers of delivery chains. After that, the sheet is released from the grippers at the convey terminal end and drops onto a pile board to be stacked there. Since the sheet conveyed by the delivery chains is gripped by the grippers only at its leading edge, the trailing edge of the sheet may flutter. Also, when the sheet is released to drop, an inertia occurs as the sheet travels, and the edge of the sheet may not be aligned when stacked.
In order to prevent this, a plurality of suction wheels line up below the sheet under conveyance on the upstream sheet convey direction side of the pile board in the widthwise direction of the sheet. The suction wheels have suction surfaces which draw the sheet by suction in slidable contact with it and rotate at a peripheral speed lower than the sheet convey speed. Thus, the traveling speed of the released sheet that has been gripped by the grippers is decreased. In double-sided printing, if the suction wheels described above are located within a pattern printed on the reverse surface of the sheet, the suction surfaces of the suction wheels damage the image portions printed on the sheet to degrade the printing quality. Hence, the suction wheels must be located in non-image portions which are not printed.
If non-image portions do not exist other than the two ends of the sheet in the widthwise direction or the number of non-image portions is small, the number of suction wheels is limited, and the center of the sheet becomes slack between the suction wheels, that is, so-called middle slack occurs. When such middle slack occurs, the two ends of the sheet may be disengaged from the suction wheels and are not drawn by them by suction, so the sheet convey speed cannot be sufficiently decreased. As a result, the sheet flutters. When the sheet is stacked, the edge of the sheet is not aligned well, and comes into contact with the brackets of the suction wheels to damage the printing surface.
In order to solve this, an apparatus is proposed as shown in Japanese Patent Laid-Open No. 2000-95409, which comprises a plurality of suction wheels which are arranged in the widthwise direction of a sheet to be conveyed, and at least a pair of nozzles which are arranged below the sheet on the two sides of the sheet to sandwich the center of the sheet in the widthwise direction. The pair of nozzles discharge air to blow upward the sheet under conveyance. In this apparatus, the air discharge directions from the nozzles are directed outwardly in the widthwise direction of the sheet to correct the middle slack, in which the sheet becomes slack downward, by an air layer formed by air from the nozzles. Thus, the two ends of the sheet are not disengaged from the suction wheels.
In the delivery device in the conventional sheet-fed offset rotary printing press, to prevent the middle slack of the sheet, the nozzles are additionally arranged in addition to the suction wheels. This increases the number of components. Also, in addition to a hose to communicate suction air to the suction wheels, a hose to supply discharge air to the nozzles is also required. This makes the structure complicated to increase the manufacturing cost.
It is an object of the present invention to provide a delivery device in a sheet-fed offset rotary printing press, in which a structure to prevent middle slack of a sheet-type object to be delivered is simplified to decrease the manufacturing cost.
In order to achieve the above object, according to the present invention, there is provided a delivery device in a sheet-fed offset rotary printing press, comprising a plurality of suction units which are arranged above a pile board on an upstream sheet convey direction side below a sheet under conveyance in a widthwise direction of the sheet and which draw by suction the sheet under conveyance in slidable contact therewith, at least one discharge unit which replaces one of the plurality of suction units which is other than those on two ends and which discharges air outwardly in the widthwise direction of the sheet under conveyance, at least one support member on which one of the plurality of suction units which is other than those on the two ends and the discharge unit can be mounted selectively, and air switching means for supplying suction air to the suction unit when the suction unit is mounted on the support member and supplying discharge air to the discharge means when the discharge means is mounted on the support member.
A delivery device for a sheet-fed offset rotary printing press according to an embodiment of the present invention will be described with reference to FIGS. 1 to 10.
Referring to
A pile board 7 with four corners suspended by four elevating chains 8 moves vertically when a motor (not shown) rotates clockwise/counterclockwise. A flat rectangular parallelepiped pallet 9 having a hole where the forks of a fork lift or the like can be inserted is placed on the pile board 7. On the upstream sheet convey direction (a direction of an arrow B) side of the pile board 7, five suction units 10A to 10E comprising suction wheels arranged below the sheet 6 under conveyance line up in the widthwise direction (directions of arrows C and D) of the sheet 6 under conveyance, i.e., in a direction perpendicular to the convey direction (directions of an arrow A and the arrow B) of the sheet 6, as shown in
As shown in
The screw shafts 17A and 17B which support support members 25A, 25B, 25D, and 25E to be movable in the sheet widthwise direction are longitudinal feed inverse helical screws and each have a screw pitch that is larger on the outer side than on the inner side. A support member 25C which is located at the center has no threaded portion and does not move accordingly. Hence, the gap between a discharge unit 80 and suction unit 10 in the widthwise direction of the sheet 6 under conveyance is adjusted in accordance with the size of the sheet 6.
A rotating shaft 19 is rotatably supported between the pair of subframes 13A and 13B. When a motor (not shown) rotatably drives the rotating shaft 19 clockwise/counterclockwise, the subframes 13A and 13B move in the directions of the arrows A and B with respect to the pair of delivery frames 2 through pinions 20 and racks (not shown) axially mounted on the two ends of the rotating shaft 19. A sheet lay 21 which abuts against the trailing edge of the sheet 6 dropping onto the pile board 7 to align it has a large number of air vent holes 21a and is attached to the stay 14 to extend in the directions of the arrows C and D.
As shown in
The suction units 10A to 10E and the support members 25A to 25E which support them will be described with reference to FIGS. 4 to 6. The suction units 10A to 10E and the support members 25A to 25E have the same basic structure. Hence, only the suction unit 10E and support member 25E will be described hereinafter, and the remaining suction units 10A to 10D and support members 25A to 25D will be described when necessary.
As shown in
As shown in
A coming-out preventive member 40 is mounted on the other end of the sleeve 35 with a set screw. The coming-out preventive member 40 and a step 35a formed on the sleeve 35 sandwich the support member 25E. Thus, when the support member 25E moves in the directions of the arrows C and D, the sleeve 35 moves together with the support member 25E. A slide member 38B fitted on the driving shaft 16 is mounted on the outer surface of the coming-out preventive member 40.
A substantially cylindrical moving element 42 having a threaded portion 42a to threadably engage with the screw shaft 17B is fitted in the through hole 33 of the support member 25E. A ring member 43 axially mounted on one end of the moving element 42 and a step 42b of the moving element 42 sandwich the support member 25E. When the moving element 42 moves in the directions of the arrows C and D, the support member 25E also moves together with the moving element 42 in the directions of the arrows C and D. As shown in
As shown in
As shown in
As shown in
As described above, when the support target member 26E is mounted on the support member 25E, the upper end opening 45a of the air passage 45 comes into contact with the lower end opening 68b of the air passage 68, so the air passage 45 of the support member 25E communicates with the air passage 68 of the support target member 26E, as shown in
As shown in
The air blowing boxes 80A and 80C and an air blowing box 80B (discharge units) will be described with reference to
As shown in
The hollow body 82 has five air blowing ports 87B and a large number of small-diameter discharge ports 88. The air blowing ports 87B blow air outwardly (the direction of the arrow D) in the widthwise direction of the sheet 6 under conveyance. The discharge ports 88 discharge air upward. A pair of screw holes 89 are formed in the front surface in the direction of the arrow A of the hollow body 82. As shown in
The air blowing boxes 80B and 80C are different from the air blowing box 80A described above in the direction of air discharged from air blowing ports 87. More specifically, as shown in
Five air supply devices 100A to 100E shown in
The air intake source 101 and air exhaust source 102 are connected to the air supply devices 100A to 100E through a switching device 103. The switching device 103 comprises an air intake passage 105 which is connected to the intake source 101 through a hose 104, an air blowing passage 107 which is connected to the air exhaust source 102 through a hose 106, an air supply passage 109 which is connected to the hose joint 46 through a common hose 108, and a switching valve 110 which selectively changes over the air passage 109 between the air passages 105 and 107.
The switching valve 110 has a notch 110a with a semilunar section. When the notch 110a is at the position indicated by an alternate long and two short dashed line in
Delivery operation in the delivery device having the above arrangement will be described. First, a case will be described when the convey speed of the sheet delivered by the suction units 10A to 10E is to be decreased. In this case, the support target members 26 are mounted on the mount surfaces 27 of the support members 25A to 25E of all the suction units 10A to 10E with the bolts 31, as shown in
Thus, suction air is supplied to the air passages 45 of the support members 25A to 25E of all the suction units 10A to 10E, and to the air passages 68 of support target members 26A to 26D and of the support target member 26E which communicate with the corresponding air passages 45. The suction air supplied to the air passages 68 is then supplied to the air ducts 67, so the sheet 6 under conveyance is drawn by suction by the suction surfaces 66b of the suction belts 66 which oppose the air ducts 67.
Referring to
The sheet 6 which is released from the gripper units 5 to drop at the convey terminal end of the delivery device 1 is drawn by suction at its trailing edge by the suction surfaces 66b of the five suction belts 66 to be in slidable contact with them. Thus, the traveling speed of the sheet 6 is decreased, so the sheet 6 is stacked on the pallet 9 on the pile board 7.
A case will be described wherein the delivery device is to be shifted from single-sided printing to double-sided and the conditions of the non-image portions are not met. More specifically, assume that the number of non-image portions is limited and non-image portions are not provided at the center in the widthwise direction of the sheet 6, or even if they are provided, their widths are narrow. In such a case, the three suction units 10B, 10C, and 10D cannot be arranged to be located at the center in the widthwise direction of the sheet 6 under conveyance. In this case, the air blowing boxes 80A, 80B, and 80C are provided in place of the suction units 10B, 10C, and 10D.
First, the bolts 31 that mount the support target members 26B, 26C, and 26D are loosened, and the suction units 10B, 10C, and 10D are removed together with the support target members 26B, 26C, and 26D from the support members 25B, 25C, and 25D. Subsequently, the air blowing boxes 80A, 80B, and 80C are mounted on the support members 25B, 25C, and 25D with the bolts 31.
In this state, the manipulation levers 113 of the air supply devices 100A and 100E are pivoted counterclockwise, as indicated by the alternate long and two short dashed line in
Thus, discharge air is supplied to the air passages 45 of the support members 25B, 25C, and 25D, and to the air passages 84 of the air blowing boxes 80A, 80B, and 80C that communicate with the air passages 45. The discharge air supplied to the respective air passages 84 is discharged from the air blowing ports 87A and 87B and discharge ports 88 of the air blowing boxes 80A, 80B, and 80C. When the driving shaft 16 is driven to rotate by the motor (not shown), the suction belts 66 of the suction units 10A and 10E mounted on the support members 25A and 25E travel in the direction of the arrow A at a speed slightly lower than the convey speed of the sheet 6.
When delivery operation is performed in this state, air discharged from the air blowing ports 87A and 87B of the three air blowing boxes 80A, 80B, and 80C, which are arranged under the sheet 6 released from the gripper units 5 to drop at the convey terminal end of the delivery device 1, forms an air layer that flows outwardly in the widthwise direction of the sheet 6. This air layer conveys the sheet 6 to slightly float from the air blowing boxes 80A, 80B, and 80C. This prevents middle slack of the sheet 6, and the two ends of the sheet 6 will not disengage from the suction belts 66 of the suction units 10A and 10E, so that the convey speed of the sheet 6 can be decreased sufficiently. As a result, fluttering of the sheet 6 is prevented reliably, and misalignment of the edge of the sheet when stacked can be prevented, and the sheet can be prevented from coming into contact with the brackets of the suction wheels, so its printing surface will not be damaged.
Air is discharged from the discharge ports 88 of the air blowing boxes 80A, 80B, and 80C toward the lower surface of the sheet 6 under conveyance to float the sheet 6. Thus, middle slack of the sheet 6 can be prevented reliably. The trailing edge of the sheet 6, which is drawn by suction with the suction units 10A and 10E to decrease the convey speed, is guided to the sheet lay 21 by the guide members 90. Thus, the sheet 6 is stacked on the pallet 9 smoothly and reliably.
According to this embodiment, the suction units 10B to 10D and air blowing boxes 80A to 80C can be selectively mounted on the support members 25B to 25D. No discharge units need be provided in advance independently of the suction units, thus simplifying the structure. Both the mounting structures of the suction units 10B to 10D with respect to the support members 25B to 25D and the mounting structures of the discharge units 80A to 80C with respect to the support members 25B to 25D employ the bolts 31. Thus, two types of mounting structures are not needed, so the structure can be simplified and the number of components can be decreased.
The switching device 103 is provided which switches air supply from the air intake source 101/air exhaust source 102 to the suction unit 10/discharge unit 80. Thus, air can be supplied to the suction unit 10 and discharge unit 80 with the common hose 108, so the structure can be simplified and the number of components can be decreased.
In this embodiment, the three discharge units 80A to 80C are provided. Alternatively, the central unit may employ a suction unit, and the pair of units on the two sides may employ discharge units. Of the three discharge units 80A to 80C, the central unit may employ a discharge unit, and the units on the two sides may employ suction units. The sizes of the air blowing boxes 80A to 80C in the longitudinal direction may be adjustable in accordance with the sheet size. The sheet suffices as far as it is a sheet-type object.
As has been described above, according to the present invention, the suction units and discharge units can be selectively mounted on the support members. No discharge units need be provided in advance independently of the suction units, so the structure can be simplified. Two types of mounting structures are not separately needed for the suction units and discharge units, so the structure can be simplified and the number of components can be decreased. Common pipes allow communication of air between the suction units and discharge units to simplify the structure and decrease the manufacturing cost.
Number | Date | Country | Kind |
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260355/2005 | Sep 2005 | JP | national |