Abstract:
A suction unit in a sheet-fed rotary printing press includes a plurality of suction wheels, a plurality of supports, a drive shaft, a motor, a shaft, a coupling, a bearing, a sleeve, and a gear, and a knob and a screw. The suction wheels are provided below a sheet convey path to draw a sheet-like printing product in a slidable contact by suction. The supports support the suction wheels to be movable in a sheet convey direction. The drive shaft, motor, shaft, coupling, bearing, sleeve, and gear drive the suction wheels in the sheet convey direction. The knob and screw detachably fix the suction wheels to the supports. The suction wheels are connected to/disconnected from the drive shaft, motor, shaft, coupling, bearing, sleeve, and gear when the suction wheels are fixed to/released from the supports by the knob and screw.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a suction unit provided to a delivery unit in a sheet-fed rotary printing press, which draws a printing product being conveyed in a slidable contact state by suction, and decelerates it. 
     In a sheet-fed rotary printing press, a printing product (to be referred to as a sheet hereinafter) printed by a printing unit is transferred from the grippers of an impression cylinder to the grippers of delivery chains, conveyed, released from the grippers at a convey terminal end, and dropped onto a pile board and stacked there. In this delivery unit, as the sheet to be conveyed is merely gripped at its leading end by the grippers, the trailing end of the sheet may flap. When the gripped sheets are released and dropped, the ends of the stacked sheets may not be aligned since traveling inertia remains in the sheets. 
     In order to prevent this, a countermeasure is proposed as shown in Japanese Utility Model Publication No. 7-26288. According to this reference, a plurality of suction wheels each having suction surfaces are aligned near the convey terminal end in the widthwise direction of the sheet (a direction perpendicular to the convey direction). A sheet released from grippers is attached to the surfaces of the suction wheels so that the sheet convey speed is decreased. In this suction unit, the suction wheels that rotate at a peripheral velocity lower than the printed sheet convey speed are formed upstream of the delivery unit in the delivery direction. The suction surfaces connected to a suction air source are formed in the circumferential surfaces of the suction wheels to draw a sheet by suction while coming into slidable contact with the sheet. 
     When the suction unit having the above arrangement is used in a perfector, if the suction wheels are arranged at positions corresponding to an image printed on the lower surface of the sheet, the suction surfaces of the suction wheels damage the image printed on the sheet to degrade the printing quality. For this reason, the suction wheels must be arranged to correspond to non-image areas where an ink is not attached to the sheet. In the non-image areas, the number of images changes depending on plate making for the image (image assignment in the widthwise direction of the sheet). Accordingly, the number of suction wheels must also be changed in accordance with the number of images. 
     In the conventional suction unit of the sheet-fed rotary printing press, since a drive shaft extends through the suction wheels, the suction wheels cannot be removed from the drive shaft. If some wheels may not be used as the result of a change in image plate making, unnecessary suction wheels must be moved to the outer side of the sheet width, which is cumbersome. 
     In a printing press serving as both a perfecter and a single-sided printing press, when double-sided printing is to be performed, suction wheels each having a width smaller than the width of a non-image area are required. In single-sided printing, when high-speed printing is to be performed on a thick sheet, wide suction wheels having a large suction force are required. When these suction wheels are required, the entire assembly of the suction wheel is exchanged. Alternatively, both suction wheels required for double-sided printing and single-sided printing are mounted in the suction wheel assembly, and an unnecessary suction wheel is moved outside the sheet in the sheet widthwise direction, as described above. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a suction unit in a sheet-fed rotary printing press, the position and number of which can be changed easily in accordance with a change in number and position of non-image areas. 
     In order to achieve the above object, according to the present invention, there is provided a suction unit in a sheet-fed rotary printing press, comprising a plurality of suction members provided below a sheet convey path to draw a sheet-like printing product in a slidable contact by suction, a plurality of support members for supporting the suction members to be movable in a sheet convey direction, a drive mechanism for driving the suction members in the sheet convey direction, and a fixing member for detachably fixing the suction members to the support members, wherein the suction members are connected to/disconnected from the drive mechanism when the suction members are fixed to/released from the support members by the fixing member. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view schematically showing a delivery unit for a sheet-fed rotary printing press; 
     FIGS. 2A and 2B are plan views respectively showing the right and left halves of a suction unit in a sheet-fed rotary printing press according to an embodiment of the present invention; 
     FIG. 3 is a sectional view taken along the line III—III of FIG. 2A; 
     FIG. 4 is a sectional view taken along the line IV—IV of FIG. 2A; 
     FIG. 5 is a sectional view taken along the line V—V of FIG. 2A; 
     FIG. 6A is a sectional view taken along the line V′—V′ of FIG. 2A, and FIG. 6B is a sectional view taken along the line VI′—VI′ of FIG. 6A; 
     FIG. 7 is a sectional view taken along the line VI—VI of FIG. 2A; 
     FIGS. 8A and 8B are views for explaining the positions of suction wheels in the case of four-surface printing and two-surface printing, respectively; and 
     FIGS. 9A and 9B are views for explaining the positions of the suction wheels when the paper size is changed. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The present invention will be described in detail with reference to the accompanying drawings. 
     FIG. 1 shows a delivery unit in a sheet-fed rotary printing press according to an embodiment of the present invention. Referring to FIG. 1, a pair of sprockets  3  are rotatably provided to the rear portion, in the sheet convey direction, of a pair of opposing frames  2   a  and  2   b  of a delivery unit  1 . A pair of sprockets  4  are rotatably provided to the front portion, in the sheet convey direction, of the frames  2   a  and  2   b.  A pair of delivery chains  5  extend between the sprockets  3  and  4 . 
     Gripper bars  6  extend between the delivery chains  5  at a predetermined pitch. Each gripper bar  6  is provided with a gripper unit (not shown) composed of a gripper and a gripper pad. In this arrangement, as the delivery chains  5  travel, a sheet  7  printed by the printing apparatus main body is conveyed in a direction of an arrow A as it is gripped by the gripper units. At the convey terminal end, the sheet  7  is released from the gripper units and dropped onto a pile board  8  to be stacked on it. The sheets  7  dropped and stacked on the pile board  8  are aligned in the vertical direction by abutting their leading ends against a paper lay  9 , and in the horizontal direction by a side jogger plate  10 . A suction unit  12  is provided upstream of the convey terminal end of the delivery unit  1  to reduce the traveling inertia of the sheet  7  under transfer to the pile board  8 . 
     The suction unit  12  will be described with reference to FIGS. 2A and 2B. 
     The suction unit  12  is provided with a pair of opposing frames  15  and  16 . A pair of stays  17  and  18  extend between the frames  15  and  16 , and a shaft  19  also horizontally extends between the frames  15  and  16 . The shaft  19  is rotated by a drive unit (not shown) to move the suction unit  12  in the vertical direction of the sheet  7 . A shaft  22  of a motor  21  fixed to the frame  16  is connected, through a coupling  23 , to the projecting end, projecting from the frame  16 , of a drive shaft  20  rotatably supported between the frames  15  and  16 . A support  24  extending between the stays  17  and  18  supports the shaft  19  and rotatably, axially supports the drive shaft  20  through a bearing. 
     A support plate  26  is attached to the outer side of the frame  15  through studs  25 , and a cylindrical operation shaft  27  is rotatably supported by the support plate  26 . A handle  28  is axially mounted on one end of the operation shaft  27  which projects from the support plate  26 , and one end of a connecting shaft  29  is fitted in and fixed to the other end of the operation shaft  27 . When a head  30   a  of an operation shaft movement adjusting member  30  threadably engaging with the threaded portion of the frame  15  is rotated with a spanner or the like, all the suction wheels move at once in a direction of arrows B-C. Movement of the operation shaft movement adjusting member  30  is regulated by urging the distal end of a set screw  31  against the threaded portion on the surface of the operation shaft movement adjusting member  30 . 
     The connecting shaft  29  is rotatably supported in a through hole  30   b  extending through the operation shaft movement adjusting member  30  in the axial direction. A pair of rings  32  are axially mounted on the connecting shaft  29  to sandwich the two ends of the operation shaft movement adjusting member  30 , thereby regulating the movement of the connecting shaft  29  in the axial direction (the direction of the arrows B-C). A pointer  33  is attached to the connecting shaft  29  such that it moves together with the connecting shaft  29  when the connecting shaft  29  moves in the axial direction, while it is rotatable when the connecting shaft  29  moves in the rotating direction. A scale  34  is formed on the stay  17  to correspond to the distal end of the pointer  33 . 
     The other end of the connecting shaft  29  is connected to one end of a first screw rod  35  through a connecting member  36 . The axis of the first screw rod  35  coincides with that of the connecting shaft  29 . The first screw rod  35  rotates together with the connecting shaft  29 . The other end of the first screw rod  35  is connected to one end of a second screw rod  37 . The axis of the second screw rod  37  coincides with that of the first screw rod  35 . The second screw rod  37  rotates together with the first screw rod  35 . The other end of a shaft portion  37   a,  which corresponds to a portion of the second screw rod  37  extending from substantially its center to the other end not formed with a threaded portion, is connected to one end of a third screw rod  39  through a connecting member  38 . The axis of the third screw rod  39  coincides with that of the shaft portion  37   a.  The third screw rod  39  rotates together with the shaft portion  37   a.    
     The other end of the third screw rod  39  is connected to one end of a fourth screw rod  40 . The axis of the fourth screw rod  40  coincides with that of the third screw rod  39 . The fourth screw rod  40  rotates together with the third screw rod  39 . The other end of the fourth screw rod  40  is connected to one end of a shaft  42  through a connecting member  41 . The axis of the shaft  42  coincides with that of the fourth screw rod  40 . The shaft  42  rotates together with the fourth screw rod  40 . 
     The shaft  42 , the shaft portion  37   a  of the second screw rod  37 , and the connecting shaft  29  are rotatably supported through the support  24  extending between the stays  17  and  18 , and another support (not shown). The pitches of the first and fourth screw rods  35  and  40  located on two end sides of the frames  15  and  16  are set to be substantially twice those of the second and third screw rods  37  and  39 , respectively, located at the center of the frames  15  and  16 . The first and second screw rods  35  and  37  form right-hand threads, and the third and fourth screw rods  39  and  40  form left-hand screws. 
     Four suction wheel units  45 A,  45 B,  45 D, and  45 E, and one suction wheel unit  45 C are axially mounted on the first to fourth screw rods  35 ,  37 ,  39 , and  40 , and the shaft portion  37   a  of the second screw rod  37 , respectively. The suction wheel units  45 A to  45 E have the same structure. 
     The structure of the suction wheel unit  45 A will be described with reference to FIG.  4 . Referring to FIG. 4, the suction wheel unit  45 A is constituted by a suction wheel  46 A, a duct  47 , and a lid  48  interposed between the duct  47  and suction wheel  46 A. The suction wheel  46 A is formed with a large number of slit-like air paths  46   a  in the rotational direction of the suction wheel  46 A at the equal pitch. One side surface and a circumferential end face of each air path  46   a  are open. The openings in the circumferential end face of the suction wheel  46 A form suction holes  46   b.  The large number of suction holes  46   b  are formed in the circumferential surface of the suction wheel  46 A at the equal pitch. 
     The lid  48  is made of a flat plate having substantially the same outer diameter as the outer diameter of the suction wheel  46 A, and a window  48   a  having a semicircular shape when seen from the side surface is formed in the upper portion of the lid  48 . The duct  47  is formed with a hollow portion  47   a  having one side surface that opens to the lid  48 . 
     In this structure, the lid  48  is fixed to the duct  47  with a set screw  49  such that its window  48   a  opposes the hollow portion  47   a.  A screw  51  is fitted in the center hole of the suction wheel  46 A through a sleeve  50 , and the screw  51  extends also through the center hole of the duct  47 . When a nut  52  is threadably engaged with the screw  51 , the suction wheel  46 A is rotatably supported by the duct  47  through the sleeve  50 . The suction wheel unit  45 A is fixed to a support  55 A with a screw  57  having a knob  56 . A through hole  55   b,  through which the drive shaft  20  extends through a sleeve  62 , is formed in the support  55 A. 
     As shown in FIG. 3, a bush  58  formed with a threaded portion to threadably engage with the first screw rod  35  is fitted on and fixed to the support  55 A such that its circumferential movement is regulated by a rotation preventive member  58   a . A paper guide  53  is screwed to the duct  47 . 
     The second, third, and fourth screw rods  37 ,  39 , and  40  respectively threadably engage with the threaded portions of bushes  58  of supports  55 B,  55 D, and  55 E of the suction wheel units  45 B,  45 D, and  45 E. A through hole (not shown) where the shaft portion  37   a  of the second screw rod  37  is to be inserted is formed in a support  55 C of the central suction wheel unit  45 C. 
     The arrangement of the suction wheel unit  45 B will be described with reference to FIG.  5 . The suction wheel unit  45 D is identical to the suction wheel unit  45 B. 
     The suction wheel unit  45 B is different from the suction wheel unit  45 A in that the suction wheel unit  45 B can be adjusted to be movable in the direction of the arrows B-C. Referring to FIG. 5, a pivotal member  53  formed with a small-diameter portion  53   a  threadably engages with the second screw rod  37 . A support  54 B is integrated with the duct  47  by a set screw  54   a . The small-diameter portion  53   a  of the paper guide  53  extends through a through hole formed in the lower portion of the support  54 B. This support  54 B is sandwiched by a removal preventive ring  54   b  and a step  53   b  of the pivotal member  53 , and moves together with the pivotal member  53  in the direction of the arrows B-C. 
     A bolt  54   c  threadably engages with the support  54 B. The pivotal member  53  is fixed to the support  54 B by screwing the bolt  54   c . When the bolt  54   c  is loosened, the pivotal member  53  can pivot. When the pivotal member  53  is pivoted, the suction wheel unit  45 B is movably adjusted in the direction of the arrows B-C through the support  54 B. 
     As shown in FIG. 6A, a hollow portion  55   c  extending in the back-and-forth direction of the sheet is formed in the lower portion of the support  55 A. One end side of the hollow portion  55   c  communicates with the hollow portion  47   a  of the duct  47 . An opening formed at the other end side of the support  55 C is connected to one end of a hose  59  which is connected to a suction air source (not shown) at its other end. Namely, the air paths  46   a  of the suction wheel  46 A, the window  48   a  of the lid  48 , the hollow portion  47   a  of the duct  47 , the hollow portion  55   c  of the support  55 A, and the hose  59  communicate with each other. 
     Therefore, the outer air near the suction holes  46   b  of the suction wheel  46 A is drawn by the suction air source through the air paths  46   a , the window  48   a , the hollow portion  47   a  of the duct  47 , the hollow portion  55   c  of the support  55 A, and the hose  59 , to attract the sheet  7  by the circumferential surface of the suction wheel  46 A. 
     The hose  59  is made of a flexible member and connected to the suction air source with a margin. Accordingly, even when the suction wheel unit  45 A is moved as will be described later, the hose  59  is kept connected to the suction air source. 
     A structure for rotatably driving the suction wheel  46 A will be described with reference to FIGS. 6A and 6B, and FIG.  7 . 
     As shown in FIG. 6A, the diameter of the through hole  55   b  of the support  55 A is larger than the diameter of the drive shaft  20 , and a bearing  60  is arranged in the through hole  55   b . The sleeve  62  fitted on the drive shaft  20  has a two-forked portion on which a spring  66  is wound. As shown in FIG. 6B, these portions constitute a pair of arcuate rotation transmitting portions  62   a  opposing each other. The sleeve  62  is inserted in the through hole  55   b  of the support  55 A through the bearing  60 . The support  55 A is sandwiched by a pair of removal preventive rings  63  fixed to the sleeve  62 , to regulate the axial movement of the sleeve  62  with respect to the support  55 A. 
     As shown in FIG. 6B, a pair of arcuate holders  65  having an outer diameter slightly larger than the outer diameter of the rotation transmitting portions  62   a  are interposed between the rotation transmitting portions  62   a  of the sleeve  62 . The spring  66  is wound on the holders  65  to press them against the drive shaft  20  with its fastening force. Since the spring  66  fastens the holders  65 , the holders  65  integrally rotate to follow rotation of the drive shaft  20 . As the holders  65  rotate, the pair of rotation transmitting portions  62   a  also rotate to transmit rotation of the drive shaft  20  to the sleeve  62 . 
     As shown in FIG. 7, a gear  68  which rotates together with the sleeve  62  is fitted on and fixed to one end of the sleeve  62  through a bush  67 . The gear  68  having teeth at the same pitch as that of the suction holes  46   b  of the suction wheel  46 A meshes with the suction holes  46   b . When the drive shaft  20  is rotated by the motor  21 , the gear  68  rotates through the holders  65  and sleeve  62 , so that the suction wheel  46 A also rotates about the sleeve  50  as the rotation center, as shown in FIG.  4 . 
     In this case, the outer diameter of the rotation transmitting portions  62   a  of the sleeve  62  is smaller than the outer diameter of the holders  65 . Therefore, the sleeve  62  is supported to be movable with respect to the drive shaft  20  in the axial direction, i.e., in the widthwise direction (the direction of the arrows B-C) of the sheet. The sleeve  62  and the support  55 , the axial movement of which is regulated, can also move with respect to the drive shaft  20  in the direction of the arrows B-C. 
     The sheet suction operation of the suction unit in the sheet-fed rotary printing press having the above arrangement will be described. 
     Referring to FIG. 1, after printing, the sheet  7  is gripped by the gripper units of the pair of delivery chains  5  and conveyed to the delivery sheet pile board  8 . At the convey terminal end, when the gripped end of the sheet  7  passes the suction wheels  46 A to  46 E, the sheet  7  travels in slidable contact with the suction wheels  46 A to  46 E. In this case, in FIGS. 2A and 2B, upon rotation of the motor  21  and drive shaft  20 , the respective gears  68  also rotate through the respective sleeves  62  of the suction wheel units  45 A to  45 E, thereby rotating the suction wheels  46 A to  46 E. The outer air near the suction wheels  46 A to  46 E is drawn by the suction air source (not shown) through the suction holes  46   b . Therefore, the sheet  7  is conveyed as it is attached to the circumferential surfaces of the suction wheels  46 A to  46 E. 
     As a result, the speed of the sheet  7  at portions other than its gripped side becomes lower than the convey speed, and the sheet  7  is kept taut in the horizontal state. Accordingly, the traveling inertia of the sheet  7  is attenuated, and the sheets dropped and stacked on the pile board  8  are aligned well. 
     How to remove non-use suction wheels in accordance with a change in image plate making for the sheet  7  will be described with reference to FIGS. 8A and 8B. 
     Referring to FIG. 8A, when four-surface printing is to be performed to print an image on the sheet  7 , four image areas  70 A to  70 D and five non-image areas  71 A to  71 E are assigned to the sheet  7 . In this case, the suction wheels  46 A to  46 E are positioned to respectively correspond to the non-image areas  71 A to  71 E. 
     As shown in FIG. 8B, when the number of images in plate making is to be reduced to switch to two-surface printing, two image areas  72 A and  72 B and three non-image areas  73 A to  73 C are assigned to a sheet  7   a . In this case, since the suction wheels  46 B and  46 D, which have been positioned to correspond to the non-image areas  71 B and  71 D, correspond to the image areas  72 A and  72 B, the suction wheels  46 B and  46 D cannot be used. 
     To cope with this situation, in FIG. 4, the suction wheels  46 B and  46 D are removed by rotating the knobs  56  of the screws  57  of the corresponding supports  55  to disengage the screws  57  from the ducts  47 , and the suction wheel units  45 B and  45 D are removed from their supports  55 . 
     When double-sided printing is to be switched to single-sided printing to perform printing on a thick sheet at a high speed, all the suction wheels  46 A to  46 E are removed by rotating the knobs  56 . Instead, wide suction wheels are mounted on the supports  55  of the suction wheel units  45 A to  45 E by operation reverse to that described above. 
     According to this embodiment, when image plate making is to be changed, the suction wheels  46 B and  46 D corresponding to the image areas  72 A and  72 B can be easily removed by rotating the knobs  56 , leading to an improved operability. 
     When high-speed single-sided printing is to be performed on a thick sheet, a large suction force can be obtained with wide suction wheels. This solves conventional flapping of the trailing end of the sheet, or misalignment of the ends of the stacked sheets occurring due to the traveling inertia which is left when the gripped sheets are released and dropped. In double-sided printing, narrow wheels that can stop sheets at positions matching the image can be mounted. Therefore, slacking of the sheet at the intermediate portion can be prevented. 
     The suction wheel positioning operation which is performed when the size or image of the sheet  7  is changed will be described with reference to FIGS. 9A and 9B. 
     Referring to FIG. 9A, image plate making of the sheet  7  is determined as four-surface printing, and the four image areas  70 A to  70 D and the five non-image areas  71 A to  71 E are assigned to the sheet  7 . The suction wheels  46 A to  46 E are positioned to correspond to the non-image areas  71 A to  71 E. 
     As shown in FIG. 9B, when the size of the sheet  7  is changed to a larger sheet  7 A, the widths of image areas  72 A to  72 D become larger than the widths of image areas  70 A to  70 D of the sheet  7  by L. In this case, non-image areas  73 A,  73 B,  73 D, and  73 E are assigned with a larger span than that of the non-image areas  71 A,  71 B,  71 D, and  71 E of the sheet  7  with reference to a center G—G in the widthwise direction of the sheet. More specifically, the non-image areas  73 D and  73 E are assigned at positions shifted from the non-image areas  71 D and  71 E, located to the left from the center G—G in the widthwise direction of the sheet, to the left by distances L and 2L, respectively. The non-image areas  73 A and  73 B are assigned at positions shifted from the non-image areas  71 A and  71 B, located to the right from the center G—G in the widthwise direction of the sheet, to the right by distances L and 2L, respectively. 
     The handle  28  is rotated to rotate the operation shaft  27 , thereby rotating the first to fourth screw rods  35 ,  37 ,  39 , and  40  through the connecting shaft  29 . The respective supports  55  of the suction wheel units  45 A to  45 E are supported by the drive shaft  20  through the sleeve  62  to be movable in the direction of the arrows B-C. Thus, when the screw rods  35 ,  37 ,  39 , and  40  are rotated, the supports  55 , the bushes  58  of which threadably engage with the screw rods  35 ,  37 ,  39 , and  40 , move in the direction of the arrows B-C as they are guided by the drive shaft  20 . 
     In this case, the first and second screw rods  35  and  37  located to the right (direction of the arrow C) from the center form right-hand threads, and the third and fourth screw rods  39  and  40  located to the left (direction of the arrow B) from the center form left-hand threads. As the screw rods  35  and  37  rotate, the suction wheel units  45 A and  45 B move in the direction of the arrow C. Simultaneously, as the screw rods  39  and  40  rotate, the suction wheel units  45 D and  45 E move in the direction of the arrow B. 
     The pitches of the first and fourth screw rods  35  and  40  serving as the outer screw rods are twice those of the second and third screw rods  37  and  39  serving as the inner screw rods. When the inner suction wheel units  45 B and  45 C move by the distance L, the outer suction wheel units  45 A and  45 E move by the distance 2L. Therefore, all of the suction wheels  46 A to  46 E are positioned simultaneously to correspond to the non-image areas  73 A to  73 E of the sheet  7 A. 
     According to this embodiment, since the positions of the counter handle side suction wheel units  45 D and  45 E are adjusted by operating one handle  28  from the center in the widthwise direction of the sheet  7 , the operability can be increased. Since the suction wheel positioning operation is performed by the handle  28  provided to the outside of the suction wheel units, the operability can be better than that of the conventional positioning operation performed inside the suction wheel units. 
     Suction wheel positioning operation which is performed when the number of images in plate making is changed or plate making is changed to nonuniform plate making will be described. 
     To change the number of images in plate making from four-surface printing to three-surface printing, the handle  28  is pivoted to move the suction wheel units  45 A to  45 E to the margins (non-image areas) on the two ends of the sheet. The bolts  54   c  (FIG. 5) of the suction wheel units  45 B and  45 D are loosened, and the pivotal members  53  are moved to move the suction wheel units  45 B and  45 D in the sheet widthwise direction (the direction of arrows B-C) separately. After the suction wheel units  45 B and  45 D are positioned at the margins (non-image areas) inside the sheet widthwise direction, the bolts  54   c  are fastened. Finally, the knobbed screw  57  of the central suction wheel unit  45 C is loosened to remove the suction wheel unit  45 C from the support  55 . As a result, the suction wheel units  45 A,  45 B,  45 D, and  45 E are positioned in the non-image areas of the sheet. 
     Adjusting operation which is performed when the center of a plate (not illustrated) is positionally offset in the sheet widthwise direction will be described. In this case, all of the suction wheels  46 A to  46 E do not correspond to the non-image areas  71 A to  71 E of the sheet  7 . 
     First, the set screw  31  (FIG. 2A) is loosened and the head  30   a  of the operation shaft movement adjusting member  30  is rotated with a spanner or the like to move the operation shaft movement adjusting member  30  in the direction of the arrows B-C. By this movement, the connecting shaft  29  is moved in the direction of the arrows B-C through the pair of rings  32 , and the screw rods  35 ,  37 ,  39 , and  40  are also moved at once in the direction of the arrows B-C by the same amount. As a result, the suction wheels  46 A to  46 E can be positioned in the non-image areas  71 A to  71 E. 
     According to this embodiment, the adjusting operation is easy, and the suction wheels  46 A to  46 E will not erroneously come into slidable contact with the ink of a printed portion, so that the printing quality can be improved. 
     To adjust movement of the suction wheels  46 A to  46 E, the positional error amount of the suction wheel  46  on the sheet  7  as the positional error amount of the plate may be set by using the pointer  33  and scale  34 . This can decrease the number of times of test printing to decrease the amount of wasted paper. Since the adjusting operation can be performed simply within a short period of time, the productivity is improved. 
     In the above embodiment, if an air source which can be switched between suction and exhaust is connected to the pipes connected to the suction wheels  46 A to  46 E, air ducts may be mounted on the supports  55  in place of the suction wheels  46 A to  46 E. In this case, if air is blown from the air ducts toward the outer side or upper side of the sheet widthwise direction, slacking of the sheet at the intermediate portion can be prevented. 
     In place of the suction wheels  46 A to  46 E, suction units having various types of pivotal belts can be mounted on the supports  55 . Therefore, the printing press can cope with various types of printing, leading to an improved versatility. The sheet  7  can be any sheet-like printing product including a film. 
     As has been described above, according to the present invention, since the suction members can be removed from the suction wheel units, a suction member which is not in use can be handled easily. Since another suction member, a paper receiving wheel, and the like can be attached and detached easily, the printing press can cope with various types of printing, leading to an improved versatility. Since the suction members can be rotatably driven with one drive shaft by utilizing the suction holes of the suction surfaces, the structure is simplified.