Printing machine

Abstract

To provide a printing machine, which has a wide region surrounded by a processing cylinder and an inversion path.SOLUTION: The printing machine, which can perform two-sided printing, comprises a processing cylinder that conveys a sheet and passes the sheet on a printing position, and an inversion path on which a printed sheet is received from the processing cylinder, and front and rear sides of the sheet are inverted and then the sheet is delivered to the processing cylinder. The inversion path includes a receiving cylinder that receives a sheet from the processing cylinder, a delivering cylinder that delivers a sheet to the processing cylinder, and an intermediate conveying part that conveys a sheet from the receiving cylinder to the delivering cylinder. The intermediate conveying part includes inverting means that inverts a sheet and at least one intermediate conveying cylinder that conveys a sheet to a downstream side of the intermediate conveying part. When a cylinder whose diameter is smallest among a plurality of cylinders is defined as a reference cylinder, the receiving cylinder and the delivering cylinder have diameters twice or more the diameter of the reference cylinder.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a printing press capable of double-sided printing on sheets. [Background technology]

[0002] Printing presses capable of double-sided printing on sheets have been known for some time (see Patent Document 1). As shown in Fig. 6, this printing press 500 includes a processing drum 501 that transports the sheets and passes them through a printing position PP1, and a reversing path 510 that receives the printed sheets from the processing drum 501, turns the sheets over, and then passes them back to the processing drum 501.

[0003] The reversing path 510 includes a reversing transfer drum 511 that receives the sheet from the processing drum 501, a reversing drum 512 that receives the tail end of the sheet (the downstream end in the conveying direction) from the reversing transfer drum 511 and passes the tail end as the head end (the upstream end in the conveying direction) to invert the sheet, and a printing side transfer drum 513 that passes the sheet received from the reversing drum 512 to the processing drum 501.

[0004] In this printing press 500, a sheet on a processing drum 501 passes through printing position PP1, whereby printing is performed on one side of the sheet, and the printed sheet is transferred to a reversing transfer drum 511 and transported along a reversing path 510. During transport along this reversing path 510, the sheet is reversed by a reversing drum 512, and then transferred to the processing drum 501 by a printing-side transfer drum 513. Then, the sheet transferred to this processing drum 501 passes through printing position PP1 again, whereby printing is performed on the other side of the sheet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6899658 Summary of the Invention [Problem to be solved by the invention]

[0006] In the printing press 500 described above, the area S1 surrounded by the processing cylinder 501 and the reversing path 510 is defined by four conveying members (the processing cylinder 501, the reversing transfer cylinder 511, the reversing cylinder 512, and the printing side transfer cylinder 513). However, because this is a narrow area, it is not easy to work within this area S1 when an operator needs to access it for maintenance, troubleshooting, etc.

[0007] Therefore, an object of the present invention is to provide a printing press in which the area surrounded by the processing cylinder and the reversing path is wide. [Means for solving the problem]

[0008] The printing press of the present invention comprises: A printing press capable of performing double-sided printing on a sheet while transporting the sheet by a plurality of cylinders, a processing cylinder for transporting the sheet through a printing position; a reversing path that receives the printed sheet from the processing cylinder, turns the sheet over, and then passes it to the processing cylinder; The reverse path is a receiving drum for receiving the sheets from the processing drum; a transfer drum that transfers the paper sheets to the processing drum; an intermediate conveying section that conveys the sheet from the receiving drum to the transfer drum, The intermediate conveying unit is a reversing means for receiving the trailing edge of the sheet from a drum positioned immediately upstream in the reversing path and passing the received trailing edge as the leading edge to a drum positioned immediately downstream, thereby reversing the sheet; at least one intermediate conveying cylinder that conveys the sheet downstream of the intermediate conveying section; When the cylinder with the smallest diameter among the plurality of cylinders is taken as a reference cylinder, each of the receiving cylinder and the transfer cylinder has a diameter that is at least twice the diameter of the reference cylinder.

[0009] According to this configuration, the area surrounded by the processing cylinder and the reversing path is defined by five or more conveying members (cylinders or reversing swings), so that the area is sufficiently large.

[0010] Further, in the printing machine, When viewed from the direction of the central axis of rotation of the processing drum, the angle formed by a first imaginary line connecting the center of rotation of the processing drum and the center of rotation of the receiving drum and a second imaginary line connecting the center of rotation of the processing drum and the center of rotation of the transfer drum may be 90° or less.

[0011] In this way, by arranging the receiving drum and the transfer drum around the processing drum so that the angle between the first imaginary line and the second imaginary line is 90° or less, it is possible to ensure the radial dimension of the processing drum in the area surrounded by the processing drum and the reversing path (see arrow β in FIG. 2 as an example). In other words, by balancing the circumferential size and radial size of the processing drum in the surrounded area, it becomes easier to access the surrounded area during maintenance, etc.

[0012] The reversing means may be a reversing swing.

[0013] With this configuration, compared to when the reversing means is a reversing cylinder, it is easier to access from the outside the area surrounded by the processing cylinder and the reversing path during maintenance, etc.

[0014] Further, in the printing machine, The intermediate conveying unit is the reversing swing receiving the sheet from the receiving cylinder; and at least one intermediate transport cylinder disposed downstream of the reversing swing.

[0015] In this way, by making all the conveying members downstream of the reversing swing in the reversing path drums (intermediate conveying drum, transfer drum), even if the sheet moves wildly due to its transport in the reversing swing, the sheet is transported along the outer peripheral surface of each drum before being handed over to the processing drum, so that the movement is contained and the flow of the sheet is stabilized.

[0016] Further, the printing machine a first drive source that drives a first intermediate transfer cylinder that is an intermediate transfer cylinder located immediately downstream of the reverse swing; The machine may further include a second drive source that drives the plurality of cylinders excluding the first intermediate transfer cylinder and the reversing swing.

[0017] In this way, by driving each drum except the first intermediate conveying drum and the reverse swing with a single drive source (second drive source), the rotation and oscillation of each conveying member (drum and reverse swing, etc.) are synchronized to prevent discrepancies in the timing of sheet transfer, while the first intermediate conveying drum, which receives sheets from the reverse swing, whose oscillation phase is changed according to sheets of different top and bottom sizes (length in the conveying direction), is driven independently with a single drive source (first drive source) to adjust the rotational speed, thereby making it possible to adjust the timing of sheet transfer to the downstream drum, and thereby effectively suppressing misalignment of the sheets during transfer.

[0018] Further, in the printing machine, The first intermediate transfer drum may deliver the sheet at a position opposite to the position where the sheet is received from the reversing swing, across the center of rotation of the first intermediate transfer drum.

[0019] In this way, by making the rotational distance of the first intermediate conveying drum from the sheet receiving position from the reverse swing to the sheet handover position to the downstream drum approximately the same as the rotational distance of the first intermediate conveying drum from the handover position to the receiving position, acceleration (positive acceleration and negative acceleration control) can be suppressed when adjusting the rotational speed in accordance with changes in the top and bottom size of the sheet being conveyed.

[0020] Further, in the printing machine, The intermediate conveying section may be composed of an inverting swing or inverting drum that receives the sheet from the receiving drum and inverts it, and an intermediate conveying drum that receives the sheet from the inverting swing or inverting drum and passes it to the transfer drum.

[0021] In this way, by configuring the reversing path so that only two conveying members (the reversing swing and the first intermediate conveying drum) are arranged between the receiving drum and the transfer drum, the distance between the receiving drum and the transfer drum in the circumferential direction of the processing drum is reduced, thereby ensuring the radial dimension of the processing drum in the area surrounded by the processing drum and the conveying path. In other words, by balancing the circumferential size and radial size of the processing drum in the area surrounded by the processing drum and the reversing path, it becomes easier to access the surrounded area during maintenance, etc. [Effects of the Invention]

[0022] As described above, according to the present invention, a printing press having a wide area surrounded by the processing cylinder and the reversing path can be provided. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a printing press according to this embodiment. [Figure 2] FIG. 2 is a schematic diagram for explaining the processing cylinder and the reversing path in the printing press. [Figure 3] FIG. 3 is a view of the intermediate transfer drum and the independent drive motor as viewed from a direction perpendicular to the direction of the central axis of rotation. [Figure 4] FIG. 4 is a view of the intermediate transfer drum as seen from the direction of the rotational axis. [Figure 5] FIG. 5 is a diagram for explaining the control of the rotation speed of the intermediate transfer drum. [Figure 6] FIG. 6 is a schematic diagram showing the configuration of a conventional printing press. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, one embodiment of the present invention will be described with reference to FIGS.

[0025] The printing press of this embodiment is a printing press capable of double-sided printing on sheets while transporting the sheets using multiple cylinders. As shown in Fig. 1, this printing press P includes a paper feed unit 1 that feeds sheets, a printing unit 2 that receives the sheets fed from the paper feed unit 1 and prints on the sheets, and a paper discharge unit 3 that discharges and stores the sheets printed in the printing unit 2. The printing press P also includes two drive sources (a main motor (second drive source) M1 and an independent drive motor (first drive source) M2).

[0026] The paper supply unit 1 supplies (feeds) stocked paper sheets to the printing unit 2. The paper supply unit 1 includes a paper supply tray 11 on which paper sheets are stocked, and a feeder 12 that supplies (feeds) the paper sheets from the paper supply tray 11 to the printing unit 2 in sequence.

[0027] Specifically, in the paper supply unit 1, the paper supply tray 11 stores stacked paper sheets, and the feeder 12 supplies the paper sheets stacked on the paper supply tray 11 to the printing unit 2 in a predetermined supply cycle, starting from the top, through the feeder board 121. In the paper supply unit 1, the supply cycle of paper sheets to the printing unit 2 during double-sided printing is twice the supply cycle to the printing unit 2 during single-sided printing.

[0028] The printing unit 2 performs double-sided printing or single-sided printing on the sheets supplied from the paper supply unit 1. The printing unit 2 includes a processing drum 22 that transports the sheets and passes them through a printing position PP, and an inversion path 25 that receives the sheets that have been printed on one side from the processing drum 22, inverts the sheets, and then passes them to the processing drum 22.

[0029] Specifically, printing unit 2 includes a swing 21 that receives and transports sheets from feeder 12, a transfer drum 255 that receives and transports sheets from swing 21, a processing drum 22 that receives and transports sheets from transfer drum 255 while passing through a printing position PP, and a reversing path 25 that reverses the sheets received from processing drum 22 and returns them to processing drum 22. Printing unit 2 also includes a print processing unit 23 that is disposed opposite the outer peripheral surface of processing drum 22 and prints on sheets being transported by processing drum 22. The position where print processing unit 23 and processing drum 22 face each other is the printing position PP.

[0030] The swing 21 is disposed at the tip end of the feeder board 121 and transports sheets from the feeder board 121 to the transfer drum 255. The swing 21 has a gripper 21g at its tip end, which is composed of a claw base and a claw, and swings around a swing axis 211. At the tip end (gripper arrangement position) of the swing 21, multiple grippers 21g are disposed at intervals in the direction of the swing axis. When the swing 21 receives a sheet, each gripper 21g grips (squeezes) the sheet with the claw base and claw, and when the swing 21 passes the sheet, the gap between the claw base and claw opens, releasing the gripped sheet.

[0031] The transfer drum 255 is disposed adjacent to the swing 21 and rotates around a rotation center C1 to transport sheets from the swing 21 to the processing drum 22. As shown in FIG. 2 , the transfer drum 255 of this embodiment is disposed adjacent to the processing drum 22 so that the rotation center C1 of the transfer drum 255 is located below the rotation center C2 of the processing drum 22.

[0032] Furthermore, the transfer drum 255 of this embodiment also serves as the most downstream drum among the multiple drums included in the reversing path 25. That is, the transfer drum 255 is included in the sheet transport path from the paper feed unit 1 to the processing drum 22, and is also included in the reversing path 25. Therefore, the transfer drum 255 can also transport (transfer) the sheet transported along the reversing path 25 to the processing drum 22.

[0033] Specifically, the transfer drum 255 is provided with grippers 255g at two locations in the circumferential direction. At each location of the grippers 255g in the circumferential direction (hereinafter simply referred to as "gripper location locations"), multiple grippers 255g are arranged at intervals in the direction of the central axis of rotation of the transfer drum 255. In the transfer drum 255 of this embodiment, the grippers 255g at the two locations are arranged at equal intervals in the circumferential direction. The configuration of each gripper 255g is the same as that of the gripper 21g of the swing 21. The transfer drum 255 is configured so that the temperature of the outer periphery can be adjusted.

[0034] The transfer cylinder 255 is a so-called double cylinder that has grippers 255g at two circumferential locations and has a diameter twice that of a reference cylinder (hereinafter referred to as a "diameter reference cylinder"). Here, the diameter reference cylinder is the cylinder with the smallest diameter among the multiple cylinders that transport sheets in the printing press P. In the printing press P of this embodiment, the diameter reference cylinders are the first to third delivery cylinders 321 to 323, etc.

[0035] The processing drum 22 is disposed adjacent to the transfer drum 255, and while rotating about a rotation center C2, transports the paper sheet from the transfer drum 255 to the paper discharge section 3 (specifically, the first paper discharge drum 321) or the reversal path 25 (specifically, the receiving drum 251). The processing drum 22 transports the paper sheet so that it passes through a position (printing position) PP opposite the print processing section 23.

[0036] Specifically, the processing cylinder 22 is provided with grippers 22g at three locations in the circumferential direction. At each gripper location, multiple grippers 22g are arranged at intervals in the direction of the central axis of rotation of the processing cylinder 22. In the processing cylinder 22 of this embodiment, the three grippers 22g are arranged at equal intervals in the circumferential direction. The configuration of each gripper 22g is the same as that of the gripper 21g of the swing 21.

[0037] The processing drum 22 has a large number of suction holes arranged on its outer circumferential surface, which attracts almost the entire area of ​​the sheet to the outer circumferential surface during transport, thereby preventing the sheet from floating from the outer circumferential surface during transport.

[0038] The processing cylinder 22 is a so-called triple cylinder, which has grippers 22g at three locations in the circumferential direction and has a diameter three times the diameter of the diameter reference cylinder.

[0039] The print processing unit 23 is a device that prints (performs a print process) on sheets being transported by the processing drum 22, and the print processing unit 23 in this embodiment is an inkjet device. The print processing unit 23 is arranged at the printing position PP with the inkjet head facing the outer circumferential surface of the processing drum 22. Note that the print processing unit 23 is not limited to an inkjet device.

[0040] The reversing path 25 is a sheet transport path constituted by a reversing means (for example, a reversing swing 253 and a reversing drum) and a plurality of drums, and the like, and the sheet received from the processing drum 22 is inverted during transport and then passed to the processing drum 22. Specifically, the reversing path 25 includes a receiving drum 251 that receives the sheet from the processing drum 22, a transfer drum 255 that passes the sheet to the processing drum 22, and an intermediate transport section 252 that transports the sheet from the receiving drum 251 to the transfer drum 255. In the reversing path 25 of this embodiment, the reversing means is the reversing swing 253, and the intermediate transport section 252 is constituted by the reversing swing 253 and an intermediate transport drum (first intermediate transport drum) 254.

[0041] The receiving drum 251 is disposed adjacent to the processing drum 22, and rotates around a rotation center C3 while transporting sheets from the processing drum 22 to the intermediate transport section 252. In this embodiment, the receiving drum 251 is disposed adjacent to the processing drum 22 so that the rotation center C3 of the receiving drum 251 is lower than the rotation center C2 of the processing drum 22 and lower than the rotation center C1 of the transfer drum 255.

[0042] In addition, when viewed from the direction of the central axis of rotation of the processing drum 22, the receiving drum 251 and the transfer drum 255 are positioned relative to the processing drum 22 so that the angle α formed by the first imaginary line L1 connecting the rotation center C2 of the processing drum 22 and the rotation center C3 of the receiving drum 251 and the second imaginary line L2 connecting the rotation center C2 of the processing drum 22 and the rotation center C1 of the transfer drum 255 is 90° or less.

[0043] Specifically, the receiving cylinder 251 is provided with a gripper 251g at one location in the circumferential direction. At the gripper arrangement position, multiple grippers 251g are arranged at intervals in the direction of the central axis of rotation of the receiving cylinder 251. The configuration of each gripper 251g is the same as that of the gripper 21g of the swing 21. In addition, the receiving cylinder 251 has a diameter twice the diameter of the diameter reference cylinder.

[0044] The receiving drum 251 has an outer circumferential guide surface 251a that guides the paper sheets in a range from the gripper arrangement position in the circumferential direction as viewed from the direction of the central axis of rotation to a position downstream by a predetermined angle. In this embodiment, the predetermined angle is 145 degrees. Meanwhile, the outer circumferential surface of the receiving drum 251 in the circumferential direction other than the outer circumferential guide surface 251a has a smaller diameter than the outer circumferential guide surface 251a. The outer circumferential surface of the receiving drum 251 in a range downstream of the outer circumferential guide surface 251a has a smaller diameter outer circumferential surface 251b.

[0045] This guide outer peripheral surface 251a is divided into a plurality of parts at intervals in the direction of the central axis of rotation of the receiving drum 251. The tip end of the reversing swing 253 (more specifically, the gripper 253g) fits between these divided outer peripheral surfaces (divided guide outer peripheral surfaces 251a), thereby avoiding collision between the receiving drum 251 and the reversing swing 253.

[0046] The intermediate conveying section 252 includes a reversing swing 253 or a reversing drum that receives the tail end of a sheet (the rear end of the sheet in the conveying direction) from a drum located immediately upstream in the reversing path 25 and passes the received tail end as the head end (the front end of the sheet in the conveying direction) to a drum located immediately downstream, thereby reversing the sheet, and at least one intermediate conveying drum 254 that conveys the sheet downstream of the intermediate conveying section 252. The intermediate conveying section 252 of this embodiment is made up of a reversing swing 253 that receives a sheet from the receiving drum 251 and at least one intermediate conveying drum (first intermediate conveying drum) 254 (one in the example shown in FIG. 1) that is arranged downstream of the reversing swing 253.

[0047] The reversing swing 253 is disposed adjacent to the receiving drum 251 and transports sheets from the receiving drum 251 to the intermediate transport drum 254. This reversing swing 253 has the same configuration as the above-described swing 21 that receives sheets from the feeder 12. That is, the reversing swing 253 has a gripper 253g at its tip and swings around a swing shaft 2531. At the tip (gripper arrangement position) of the reversing swing 253, a plurality of grippers 253g are arranged at intervals in the direction of the swing shaft. The configuration of each gripper 253g is the same as the gripper 21g of the swing 21. The reversing swing 253 of this embodiment repeats a predetermined swinging motion.

[0048] In this embodiment, the inverting swing 253 is disposed so that the swing shaft 2531 is located below the rotation center C3 of the receiving drum 251. The inverting swing 253 is also disposed so that the swing shaft 2531 is located on the opposite side to the processing drum 22 with respect to a third imaginary line L3 connecting the rotation center C3 of the receiving drum 251 and the rotation center C4 of the intermediate transfer drum 254. This reduces the swing range of the inverting swing 253.

[0049] The reversing swing 253 can change the phase of its swinging motion in accordance with differences in the position of the tail end of a sheet being conveyed, which is based on differences in the top-bottom size (size of the sheet in the conveying direction) of the sheet received from the receiving drum 251. Specifically, a phase adjustment mechanism that adjusts the phase of the swinging motion of the reversing swing 253 is disposed midway along the transmission path (power transmission mechanism) that transmits power (driving force) from the main motor M1 to the reversing swing 253. This phase adjustment mechanism has a clutch or the like, and adjusts the phase of the swinging motion of the reversing swing 253 by transmitting and cutting off power using the clutch or the like.

[0050] The reversing swing 253 configured as described above rotates counterclockwise in FIG. 1 to grip the tail end of the sheet on the outer circumferential guide surface 251a of the receiving drum 251 with the gripper 253g, and then rotates clockwise to pass the tail end as the head of the sheet to the intermediate conveying drum 254.

[0051] The intermediate transfer drum 254 is disposed adjacent to the reversing swing 253 and rotates about a rotation center C4 to transfer sheets from the reversing swing 253 to the transfer drum 255. The intermediate transfer drum 254 is disposed so that the rotation center C4 of the intermediate transfer drum 254 is located on the opposite side to the processing drum 22 with respect to a fourth imaginary line L4 connecting the rotation center C3 of the receiving drum 251 and the rotation center C1 of the transfer drum 255. The intermediate transfer drum 254 is disposed so that the rotation center C4 is located above the rotation center C3 of the receiving drum 251 and below the rotation center C1 of the transfer drum 255.

[0052] 3 and 4, the intermediate transfer drum 254 is provided with a gripper 254g at one location in the circumferential direction. At the gripper arrangement position, multiple grippers 254g are arranged at intervals in the direction of the central axis of rotation of the intermediate transfer drum 254. The configuration of each gripper 254g is similar to that of the gripper 21g of the swing 21.

[0053] The intermediate transfer cylinder 254 is a so-called single cylinder that has a gripper 254g at one location in the circumferential direction and has a diameter substantially the same as the diameter of the diameter reference cylinder.

[0054] In this embodiment, the intermediate conveying drum 254 receives a sheet from the reversing swing 253 at a position (receiving position) P1, and delivers the sheet to the delivery drum 255 at a position (delivery position) P2 on the opposite side of the rotation center C4 of the intermediate conveying drum 254. In other words, the sheet receiving position P1 and the sheet delivery position P2 of the intermediate conveying drum 254 are spaced apart by approximately 180° in the circumferential direction.

[0055] The intermediate transfer cylinder 254 is a so-called single cylinder, but in order to avoid collision with the gripper 253g of the reverse swing 253, the outer circumferential surface 254a of the intermediate transfer cylinder 254 is formed to have a smaller diameter than the diameter of the diameter reference cylinder.

[0056] The outer periphery (outer periphery surface) of the intermediate transfer drum 254 may be configured to have circumferential grooves for collision avoidance at positions corresponding to the grippers 253g of the reverse swing 253 in the rotation axis direction.

[0057] The intermediate transfer drum 254 is independently driven by an independent drive motor M2, separate from the machine motor M1 that drives the other transfer components. This independent drive causes the intermediate transfer drum 254 to increase or decrease its rotational speed. However, because the rotational speeds (circumferential velocities) of the other drums are constant, a difference in peripheral speed occurs between the outer circumferential surface of the drum that transfers the sheet (in this embodiment, the transfer drum 255) and the outer circumferential surface 254a of the intermediate transfer drum 254. This can cause friction between the sheet being transferred to the drum that transfers the sheet (in this embodiment, the transfer drum 255) and the outer circumferential surface 254a of the intermediate transfer drum 254. For this reason, the outer circumferential surface 254a of the intermediate transfer drum 254 in this embodiment is treated with a raised cloth (velvet) to prevent scratches, thereby reducing damage to the printed layer on the printed surface or the sheet itself due to the friction. Details of the independent drive by the independent drive motor M2 will be described later.

[0058] In the printing unit 2 configured as described above, a region (bag area) S is formed that is surrounded by the processing drum 22 and the reversal path 25 when viewed from the direction of the central axis of rotation of the processing drum 22 (see the area indicated by dots in FIG. 2). In this bag area S, the outer surface of the processing drum 22 is always exposed and not covered by the sheets, even while the sheets are being transported, making it easy to access the outer surface of the processing drum 22 during maintenance, etc. Also, auxiliary devices that directly act on the outer surface of the processing drum 22 can be installed.

[0059] The paper discharge unit 3 includes a paper discharge tray 31 for storing sheets printed on one side or both sides in the printing unit 2, and a transport path 32 for transporting the sheets printed in the printing unit 2 to the paper discharge tray 31.

[0060] The conveying path 32 includes a first discharge drum 321 that receives and conveys sheets from the processing drum 22, a second discharge drum 322 that receives and conveys sheets from the first discharge drum 321, a third discharge drum 323 that receives and conveys sheets from the second discharge drum 322, a fourth discharge drum 324 that receives and conveys sheets from the third discharge drum 323, and a chain delivery 325 that receives and conveys sheets from the fourth discharge drum 324.

[0061] The first delivery drum 321 is disposed upstream of the receiving drum 251 at a position where it can receive the paper sheets from the processing drum 22 .

[0062] Each of the first paper discharge drum 321, the second paper discharge drum 322, and the third paper discharge drum 323 is a so-called single drum, in which multiple grippers 321g, 322g, and 323g are arranged at intervals in the direction of the rotation axis, are arranged at one location in the circumferential direction, and have the same diameter as the diameter of the diameter reference drum.

[0063] The fourth delivery drum 324 is a so-called double drum, in which a plurality of grippers 324g are arranged at two locations in the circumferential direction with a gap in the direction of the central axis of rotation, and the diameter of the fourth delivery drum 324 is twice the diameter of the diameter reference drum.

[0064] The chain delivery 325 is disposed adjacent to the fourth discharge drum 324 and transports the paper sheets from the fourth discharge drum 324 to the paper delivery tray 31. Specifically, the chain delivery 325 is a chain-type transport device that transports the paper sheets received from the fourth discharge drum 324, and is provided with discharge grippers 325g at multiple locations (three locations in the example shown in FIG. 1) on an endlessly arranged chain (endless chain). At each location of the discharge grippers 325g in the circumferential direction of the endless chain, the multiple discharge grippers 325g are arranged at intervals in the direction of the rotational axis of a sprocket (not shown) that drives the chain. The three discharge grippers 325g are arranged at equal intervals in the circumferential direction of the endless chain.

[0065] The machine motor M1 drives the transport members (members involved in transporting sheets) excluding the intermediate transport drum 254. The transport members in the printing press P of this embodiment include the swing 21, processing drum 22, receiving drum 251, reversing swing 253, transfer drum 255, first delivery drum 321, second delivery drum 322, third delivery drum 323, fourth delivery drum 324, and chain delivery 325, and these transport members 21, 22, 251, 253, 255, 321 to 325, etc. are connected to each other by gears or the like, and are driven synchronously by the power output from the machine motor M1. As a result, the multiple cylinders 22, 251, 255, 321 to 324, excluding the intermediate transfer cylinder 254, rotate at the same peripheral speed (circumferential speed), and the swing 21 and the reverse swing 253 oscillate to match the phases of the multiple cylinders 22, 251, 255, 321 to 324.

[0066] For example, the gear of the output shaft of the motor M1 of this machine is engaged only with the gear of the processing cylinder 22, and the other conveying members 21, 251, 253, 255, 321 to 325 other than the processing cylinder 22 receive power directly or indirectly from the gear of the processing cylinder 22.

[0067] The independent drive motor M2 drives the intermediate transfer drum 254 located immediately downstream of the reversing swing 253. This independent drive motor M2 increases or decreases the rotation speed of the intermediate transfer drum 254 in accordance with a change in the phase of the oscillation of the reversing swing 253 due to differences in the top and bottom sizes of the sheets being transferred. In other words, the peripheral speed of the intermediate transfer drum 254 is increased or decreased relative to the peripheral speeds of the multiple drums 22, 251, 255, 321-324 excluding the intermediate transfer drum 254. The specific increase or decrease in the rotation speed will be described with reference to FIG. 5.

[0068] In Figure 5, t0 is the time when the gripper 254g of the intermediate conveying drum 254 receives the head of the sheet from the reversing swing 253 (i.e., the gripper 254g is located at the receiving position P1), t1 is the time when the first increase / decrease in the rotational speed of the intermediate conveying drum 254 starts, t2 is the time when the first increase / decrease in the rotational speed of the intermediate conveying drum 254 ends, t3 is the time when the gripper 254g of the intermediate conveying drum 254 passes the head of the sheet to the transfer drum 255 (i.e., the gripper 254g is located at the transfer position P2), t4 is the time when the second increase / decrease in the rotational speed of the intermediate conveying drum 254 starts, t5 is the time when the second increase / decrease in the rotational speed of the intermediate conveying drum 254 ends, and t6 is the time when the gripper 254g of the intermediate conveying drum 254 again receives the head of the sheet from the reversing swing 253. The independent drive motor drives intermediate transfer drum 254 so as to repeat a cycle from time t0 to time t6.

[0069] When the top-bottom size (length in the conveying direction) of a sheet is the standard size (medium size), the independent drive motor M2 drives the intermediate transfer drum 254 so that the intermediate transfer drum 254 rotates around the rotation center C4 at a constant speed (standard speed) until the position of the gripper 254g moves from receiving position P1 (time t1) through transfer position P2 (time t3) and then back to receiving position P1 (time t6), as shown by the bold line in Figure 5. That is, the independent drive motor M2 drives the intermediate transfer drum 254 so that the intermediate transfer drum 254 rotates at the standard speed throughout. The peripheral speed of the intermediate transfer drum 254 rotating at the standard speed is the same as the peripheral speeds of the multiple drums 22, 251, 255, 321-324 excluding the intermediate transfer drum 254.

[0070] As a result, at time t0, the gripper 253g of the reversing swing 253 and the gripper 254g of the intermediate transfer drum 254 face each other, and the intermediate transfer drum 254 receives the head of the sheet from the reversing swing 253, and the sheet is transferred in a state of being wrapped around the circumferential surface of the intermediate transfer drum 254. Then, at time t3, the gripper 254g of the intermediate transfer drum 254 and the gripper 255g of the transfer drum 255 face each other, and the head of the sheet is transferred from the intermediate transfer drum 254 to the transfer drum 255.

[0071] Next, when the top and bottom size of the sheet is the maximum size (larger than the standard size), the independent drive motor M2 drives the intermediate transfer drum 254 from times t0 to t1, t2 to t4, and t5 to t6 so that the intermediate transfer drum 254 rotates at the same standard speed as when transferring a standard-sized sheet. Then, as shown by the solid line in Figure 5, the independent drive motor M2 drives the intermediate transfer drum 254 so that the rotational speed of the intermediate transfer drum 254 gradually increases from the standard speed starting at time t1, and then returns to the standard speed at time t2. The independent drive motor M2 also drives the intermediate transfer drum 254 so that the rotational speed of the intermediate transfer drum 254 gradually decreases from the standard speed starting at time t4, and then returns to the standard speed at time t5.

[0072] Here, when the conveyed sheet is of the maximum size (larger than the standard size), the phase of the oscillation of the reversing swing 253 is delayed when it receives the sheet from the receiving drum 251, so that if the intermediate conveyance drum 254 that received the sheet from the reversing swing 253 continues to rotate at the standard speed, when the gripper 255g of the transfer drum 255 reaches the transfer position P2, the gripper 254g of the intermediate conveyance drum 254 does not reach the transfer position P2, and the sheet cannot be transferred. Therefore, when the intermediate conveyance drum 254 is driven by the independent drive motor M2, the rotation speed is increased and decreased as described above from time t1 to t2 (first speed increase / decrease region), so that when the gripper 255g of the transfer drum 255 reaches the transfer position P2, the gripper 254g of the intermediate conveyance drum 254 faces the gripper 255g, and the sheet can be transferred.

[0073] Furthermore, by reversing the change in rotational speed of the intermediate conveying drum 254 from time t4 to t5 (second speed increase / decrease region) to the change in rotational speed from time t1 to t2, the gripper 254g of the intermediate conveying drum 254 can reach the receiving position P1 at the same time that the gripper 253g of the reversing swing 253 reaches the transfer position for the sheet to the intermediate conveying drum 254.

[0074] On the other hand, when the top and bottom size of the sheet is the minimum size (smaller than the standard size), the independent drive motor M2 drives the intermediate transfer drum 254 from times t0 to t1, t2 to t4, and t5 to t6 so that the intermediate transfer drum 254 rotates at the same standard speed as when transferring a standard-sized sheet. Then, as shown by the dashed line in Figure 5, the independent drive motor M2 drives the intermediate transfer drum 254 so that the rotational speed of the intermediate transfer drum 254 gradually decreases from the standard speed starting at time t1, and then returns to the standard speed at time t2. Also, the independent drive motor M2 drives the intermediate transfer drum 254 so that the rotational speed of the intermediate transfer drum 254 gradually increases from the standard speed starting at time t4, and then returns to the standard speed at time t5.

[0075] Here, if the sheet being transported is of the minimum size (smaller than the standard size), the phase of the oscillation of the reversing swing 253 is advanced when it receives the sheet from the receiving drum 251, so that if the intermediate transfer drum 254 that has received the sheet from the reversing swing 253 continues to rotate at the standard speed, the gripper 254g of the intermediate transfer drum 254 will reach transfer position P2 before the gripper 255g of the transfer drum 255 reaches transfer position P2, making it impossible to transfer the sheet. Therefore, when the intermediate transfer drum 254 is driven by the independent drive motor M2, the rotation speed is decelerated and accelerated as described above from time t1 to t2 (first speed increase / decrease region), so that when the gripper 255g of the transfer drum 255 reaches transfer position P2, the gripper 254g of the intermediate transfer drum 254 will face the gripper 255g, making it possible to transfer the sheet.

[0076] Furthermore, by reversing the change in rotational speed of the intermediate conveying drum 254 from time t4 to t5 (second speed increase / decrease region) to the change in rotational speed from time t1 to t2, the gripper 254g of the intermediate conveying drum 254 can reach the receiving position P1 at the same time that the gripper 253g of the reversing swing 253 reaches the transfer position for the sheet to the intermediate conveying drum 254.

[0077] The outline of the operation of the printing press P configured as above during single-sided printing is as follows.

[0078] Sheets are sequentially supplied from the paper feed unit 1 to the printing unit 2 at a predetermined supply cycle. The sheets supplied to the printing unit 2 are transferred to the transfer drum 255 by the swing 21, and then conveyed in this order to the processing drum 22, the first paper discharge drum 321, the second paper discharge drum 322, the third paper discharge drum 323, the fourth paper discharge drum 324, and the chain delivery 325, and then discharged onto the paper discharge tray 31.

[0079] When a sheet is transported during single-sided printing, as the sheet is transported to the processing drum 22 and passes through the printing position PP, the printing processing unit 23 applies printing processing to one side (the outer surface in the radial direction of the processing drum 22).

[0080] On the other hand, the outline of the operation during double-sided printing is as follows.

[0081] Sheets are sequentially supplied from the paper supply unit 1 to the printing unit 2 at a supply cycle twice that of simplex printing. The sheets supplied to the printing unit 2 are transferred to the transfer cylinder 255 by the swing 21, and then conveyed in this order to the processing cylinder 22, the receiving cylinder 251, the reversing swing 253, the intermediate transfer cylinder 254, and the transfer cylinder 255, and are then transferred from the transfer cylinder 255 to the processing cylinder 22 again.

[0082] Next, the sheet of paper (the sheet of paper after being transported along the reversal path 25) is handed over again from the transfer drum 255 to the processing drum, and is transported from the processing drum 22 to the first paper discharge drum 321, the second paper discharge drum 322, the third paper discharge drum 323, the fourth paper discharge drum 324, and the chain delivery 325 in that order, and is discharged onto the paper discharge tray 31.

[0083] In the conveyance of a sheet during double-sided printing, the sheet passes through the printing position PP during the first conveyance by the processing cylinder 22, and the print processing unit 23 performs printing processing on one side of the sheet.

[0084] The sheet of paper with one side printed is passed from the processing drum 22 to the receiving drum 251 and transported along the reversing path 25 (i.e., it is transported in the order of the receiving drum 251, the reversing swing 253, the intermediate transport drum 254, and the transfer drum 255). Along the way, the sheet is reversed by the reversing swing 253, and the reversed sheet is returned to the processing drum 22.

[0085] Subsequently, when the sheet passes through the printing position PP during the second transport by the processing cylinder 22, the print processing is performed on the other side by the print processing unit 23.

[0086] The above-mentioned printing press P is a printing press P capable of printing on both sides of a sheet while transporting the sheet using multiple cylinders, and is equipped with a processing cylinder 22 that transports the sheet and passes it through the printing position PP, and an inversion path 25 that receives the printed sheet from the processing cylinder 22, inverts the sheet, and then passes it to the processing cylinder 22. The reversing path 25 includes a receiving drum 251 that receives the sheet from the processing drum 22, a transfer drum 255 that hands the sheet to the processing drum 22, and an intermediate conveying section 252 that conveys the sheet from the receiving drum 251 to the transfer drum 255. The intermediate conveying section 252 includes a reversing means 253 that receives the tail end of the sheet from a drum located immediately upstream in the reversing path 25 (in this embodiment, the receiving drum 251) and hands the received tail end as the head of the sheet to a drum located immediately downstream (in this embodiment, the intermediate conveying drum 254), thereby reversing the sheet, and at least one intermediate conveying drum 254 that conveys the sheet downstream of the intermediate conveying section 252. When the drum with the smallest diameter among the multiple drums provided in the printing press P is used as a reference drum (diameter reference drum), each of the receiving drum 251 and the transfer drum 255 has a diameter that is more than twice the diameter of the diameter reference drum.

[0087] With this configuration, the bagging area S surrounded by the processing cylinder 22 and the reversing path 25 is defined by five or more conveying members (in the example of this embodiment, the cylinders 22, 251, 254, 255 or the reversing swing 253), so that a sufficiently large bagging area S can be obtained. Moreover, in the printing press P of this embodiment, the receiving cylinder 251 and the transfer cylinder 255 in the reversing path 25 are configured as cylinders having a diameter twice that of the reference diameter cylinder (so-called double cylinders), so that stress applied to the sheets being transported in the reversing path 25 can be reduced. In other words, with the printing press P of this embodiment, stress applied to the sheets being transported in the reversing path 25 can be reduced, and a sufficiently large bagging area S can be obtained.

[0088] Furthermore, in the printing press P of this embodiment, when viewed from the direction of the rotational axis of the processing drum 22, the angle formed by the first imaginary line L1 connecting the rotational center C2 of the processing drum 22 and the rotational center C3 of the receiving drum 251 and the second imaginary line L2 connecting the rotational center C2 of the processing drum 22 and the rotational center C1 of the transfer drum 255 is 90° or less.

[0089] In this way, by arranging the receiving drum 251 and the transfer drum 255 around the processing drum 22 so that the angle between the first imaginary line L1 and the second imaginary line L2 is 90° or less, it is possible to ensure the radial dimension of the processing drum 22 in the bagging region S surrounded by the processing drum 22 and the reversal path 25 (see arrow β in FIG. 2 as an example). In other words, by balancing the circumferential size and radial size of the processing drum 22 in the bagging region S, access to the bagging region S during maintenance, etc. is made easier. Note that arrow β in FIG. 2 indicates an example of the radial direction of the processing drum 22, and the processing drum 22 may also rotate around the rotation center C2 between the receiving drum 251 and the transfer drum 255.

[0090] In addition, in the printing press P of this embodiment, the reversing means is a reversing swing 253. Therefore, compared to when the reversing means is a reversing cylinder, it is easier to access from the outside the bagging area S surrounded by the processing cylinder 22 and the reversing path 25 during maintenance, etc.

[0091] Furthermore, in the printing press P of this embodiment, the receiving cylinder 251 has a small-diameter outer peripheral surface 251b on its outer peripheral surface. By adjusting the rotation angle position of the receiving cylinder 251 so that the small-diameter outer peripheral surface 251b defines the bagging area S, the bagging area S can be further enlarged.

[0092] In addition, in the printing press P of this embodiment, the intermediate conveying section 252 is composed of an inverting swing 253 that receives sheets from the receiving drum 251, and at least one (in this embodiment, one) intermediate conveying drum 254 that is arranged downstream of the inverting swing 253.

[0093] In this way, by making all of the conveying members downstream of the reversing swing 253 in the reversing path 25 into cylinders (intermediate conveying cylinder 254, transfer cylinder 255), even if the sheet vibrates due to its conveyance on the reversing swing 253, the sheet is conveyed along the outer circumferential surface of each cylinder 254, 255 before being delivered to the processing cylinder 22, so the vibrating motion is contained and the flow of the sheet is stabilized. This configuration is particularly effective because the increase in sheet feed speed in recent years has made vibrating more likely to occur.

[0094] In addition, the printing press P of this embodiment is equipped with a single drive motor (first drive source) M2 that drives the intermediate conveying cylinder (first intermediate conveying cylinder) 254 located immediately downstream of the reversing swing 253, and a main motor (second drive source) M1 that drives multiple cylinders 22, 251, 255, 321 to 324 excluding the intermediate conveying cylinder 254 and the reversing swing 253.

[0095] In this way, by driving each of the cylinders 22, 251, 255, 321-324 and the reversing swing 253, excluding the intermediate transfer cylinder 254, with a single drive source (main motor) M1, the rotations and oscillations of the respective transport members (cylinders 22, 251, 255, 321-324 and the reversing swing 253, etc.) can be synchronized to prevent mismatches in the timing of sheet transfer. Moreover, by independently driving the intermediate transfer cylinder 254, which receives sheets from the reversing swing 253, whose oscillation phase is changed according to sheets of different top-bottom sizes (lengths in the transport direction), with a single drive source (single drive motor) M2 and adjusting its rotation speed, the timing of sheet transfer to the downstream cylinder (transfer cylinder 255 in this embodiment) can be adjusted, thereby effectively preventing misalignment of the sheet during transfer (misalignment of the head of the sheet gripped by the grippers 254g, 255g (misalignment from the designed position)).

[0096] In addition, in the printing press P of this embodiment, the intermediate conveying drum (first intermediate conveying drum) 254 receives the sheet from the reversing swing 253 at a receiving position P1, and delivers the sheet at a delivery position P2 on the opposite side of the rotation center C4 of the intermediate conveying drum 254 (see Figure 2).

[0097] In this way, by making the rotational distance of the intermediate conveying drum 254 from the receiving position P1 where the sheet is received from the reverse swing 253 to the transfer position P2 where the sheet is transferred to the downstream drum (transfer drum) 255 approximately the same as the rotational distance of the intermediate conveying drum 254 from the transfer position P2 to the receiving position P1, it is possible to suppress acceleration (positive acceleration and negative acceleration) when adjusting the rotational speed in accordance with changes in the top and bottom size of the sheet being conveyed.

[0098] Specifically, by positioning receiving position P1 opposite transfer position P2 across rotation center C4, the time from time t0 to t3 and the time from time t3 to t6 can be made the same or approximately the same, and the degree of increase or decrease in the rotational speed of intermediate conveying drum 254 (acceleration: the slope of the solid line or dashed line for the mountain-shaped speed change and the valley-shaped speed change in FIG. 5) can be made the same or approximately the same in the first speed increase / decrease region and the second speed increase / decrease region shown in FIG. 5. This makes it possible to make the rotational load on intermediate conveying drum 254 when moving from receiving position P1 to transfer position P2 and the rotational load on intermediate conveying drum 254 when moving from transfer position P2 to receiving position P1 approximately the same, preventing the load during either rotation from becoming too high.

[0099] Furthermore, as described above, by suppressing the acceleration (positive acceleration and negative acceleration) when accelerating and decelerating the rotational speed of the intermediate conveying drum 254 according to the top and bottom size of the sheet, fluttering of the sheet being conveyed on the intermediate conveying drum 254 is suppressed.

[0100] In addition, in the printing press P of this embodiment, the intermediate conveying section 252 may be composed of an inverting swing 253 that receives sheets from the receiving drum 251 and inverts them, and an intermediate conveying drum 254 that receives sheets from the inverting swing 253 and passes them to the transfer drum 255.

[0101] In this way, by configuring the reversing path 25 so that only two conveying members (the reversing swing 253 and the intermediate conveying path 254) are arranged between the receiving drum 251 and the transfer drum 255, the distance between the receiving drum 251 and the transfer drum 255 in the circumferential direction of the processing drum 22 is reduced, thereby making it possible to ensure the radial dimension of the processing drum 22 in the bag area S surrounded by the processing drum 22 and the reversing path 25. In other words, by balancing the circumferential size and radial size of the processing drum 22 in the bag area S surrounded by the processing drum 22 and the reversing path 25, it becomes easier to access the surrounded area during maintenance, etc.

[0102] In addition, in the printing press P of this embodiment, the diameter of the intermediate conveying cylinder 254 is the same as the diameter of the diameter reference cylinder (the reference cylinder), but the radial dimension of the processing cylinder 22 can be secured in the bagging area S surrounded by the processing cylinder 22 and the reversal path 25.

[0103] The printing press of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, or part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, part of the configuration of one embodiment can be deleted.

[0104] In the reversing path 25 of the printing press P in the above embodiment, the conveying member that reverses the sheet is the reversing swing 253, but is not limited to this configuration. The conveying member that reverses the sheet may also be a reversing cylinder.

[0105] In the printing press P of the above embodiment, when viewed from the direction of the central axis of rotation of the processing cylinder 22, the angle α formed between a first imaginary line L1 connecting the rotation center C2 of the processing cylinder 22 and the rotation center C3 of the receiving cylinder 251 and a second imaginary line L2 connecting the rotation center C2 of the processing cylinder 22 and the rotation center C1 of the transfer cylinder 255 is 90° or less, but is not limited to this configuration. The angle α formed between the first imaginary line L1 and the second imaginary line L2 may be greater than 90°.

[0106] Furthermore, in the printing press P of the above embodiment, in the intermediate conveying section 252, the sheet conveying path downstream of the reversing swing 253 between the reversing swing 253 and the transfer cylinder 255 is formed by one intermediate conveying cylinder 254, but is not limited to this configuration. The sheet conveying path downstream of the reversing swing 253 between the reversing swing 253 and the transfer cylinder 255 may be formed by a plurality of cylinders (intermediate conveying cylinders). In other words, the intermediate conveying section 252 only needs to have the reversing swing 253 or the reversing cylinder and at least one cylinder.

[0107] Furthermore, in the printing press P of the above embodiment, the reverse swing 253 is arranged second from the upstream end among the multiple conveying members (reverse swing 253 and cylinder) that make up the reverse path 25, but it may also be arranged third or later.

[0108] In this case, the cylinder driven by the independent drive motor (first drive source) M2 is not limited to the intermediate transfer cylinder (first intermediate transfer cylinder) 254 immediately downstream of the reversing swing 253, but may be the cylinder immediately upstream.

[0109] Furthermore, the positions of the processing cylinder 22 and the transport members (receiving cylinder 251, reversing swing 253, intermediate transport cylinder 254, transfer cylinder 255, etc.) that make up the reversing path 25 are not limited to the example shown in Fig. 1. The processing cylinder 22 and the transport members (receiving cylinder 251, reversing swing 253, intermediate transport cylinder 254, transfer cylinder 255, etc.) that make up the reversing path 25 may be positioned such that the entire body is rotated (for example, rotated around the rotation center C2) while maintaining their respective relative positions.

[0110] Furthermore, in the printing press P of the above embodiment, scratch prevention treatment was performed by attaching a raised cloth (velveteen) to the outer peripheral surface 254a of the intermediate transport drum 254, but the scratch prevention treatment is not limited to this. For example, the attachment of a glass cloth may also be used. Alternatively, a thin air layer may be formed between the paper sheets and the outer peripheral surface 254a. [Explanation of symbols]

[0111] 1...paper feed unit, 11...paper feed tray, 12...feeder, 121...feeder board, 2...printing unit, 21...swing, 21g...gripper, 211...oscillating shaft, 22...processing drum, 22g...gripper, 23...printing processing unit, 25...reversing path, 251...receiving drum, 251a...guide outer peripheral surface, 251b...small diameter outer peripheral surface, 251g...gripper, 252...intermediate conveying unit, 253...reversing swing, 253g...gripper, 2531...oscillating shaft, 254...intermediate conveying drum (first intermediate conveying drum), 254a...outer peripheral surface, 254g...gripper, 255...transfer drum, 255g...gripper, 3...paper discharge unit, 31...paper discharge tray, 32...conveying path, 321...first paper discharge drum, 321g...gripper, 322...second paper discharge drum, 322g...gripper Ripper, 323...third delivery cylinder, 323g...gripper, 324...fourth delivery cylinder, 324g...gripper, 325...chain delivery, 325g...delivery gripper, 500...printing press, 501...processing cylinder, 510...reversing path, 511...reversing transfer cylinder, 512...reversing cylinder, 513...printing side transfer cylinder, C1...rotation center of transfer cylinder, C2...rotation center of processing cylinder, C3...rotation center of receiving cylinder, C4...rotation center of intermediate transfer cylinder, L1...first imaginary line, L2...second imaginary line, L3...third imaginary line, L4...fourth imaginary line, M1...main machine motor (second driving source), M2...independent driving motor (first driving source), P...printing press, P1...receiving position, P2...transfer position, PP, PP1...printing position, S...bag area, S1...enclosed area

Claims

1. A printing press capable of performing double-sided printing on a sheet while transporting the sheet by a plurality of cylinders, a processing cylinder for transporting the sheet through a printing position; a reversing path that receives the printed sheet from the processing cylinder, turns the sheet over, and then passes it to the processing cylinder; The reversal path is a receiving drum for receiving the sheets from the processing drum; a transfer drum that transfers the paper sheets to the processing drum; an intermediate conveying section that conveys the sheet from the receiving drum to the transfer drum, The intermediate conveying unit is a reversing means for receiving the trailing edge of the sheet from a cylinder positioned immediately upstream in the reversing path and passing the received trailing edge as the leading edge to a cylinder positioned immediately downstream, thereby reversing the sheet; at least one intermediate conveying cylinder that conveys the sheet downstream of the intermediate conveying section; When the cylinder having the smallest diameter among the plurality of cylinders is taken as a reference cylinder, each of the receiving cylinder and the transfer cylinder has a diameter that is at least twice the diameter of the reference cylinder.

2. 2. The printing press according to claim 1, wherein, when viewed from the direction of the central axis of rotation of the processing cylinder, an angle formed by a first imaginary line connecting the rotation center of the processing cylinder and the rotation center of the receiving cylinder and a second imaginary line connecting the rotation center of the processing cylinder and the rotation center of the transfer cylinder is 90° or less.

3. 3. The printing press according to claim 1, wherein the reversing means is a reversing swing.

4. The intermediate conveying unit is the reversing swing receiving the sheet from the receiving cylinder; 4. The printing press according to claim 3, further comprising at least one intermediate transport cylinder disposed downstream of said reversing swing.

5. a first drive source that drives a first intermediate transfer cylinder that is the intermediate transfer cylinder located immediately downstream of the reverse swing; The printing press according to claim 3 , further comprising: a second drive source that drives the plurality of cylinders excluding the first intermediate transfer cylinder and the reversing swing.

6. 6. The printing press according to claim 5, wherein the first intermediate transport cylinder delivers the sheet at a position opposite to the position where the sheet is received from the reversing swing, across a rotation center of the first intermediate transport cylinder.

7. 2. The printing press according to claim 1, wherein the intermediate transport section is composed of a reversing swing or reversing cylinder that receives the sheet from the receiving cylinder and inverts it, and an intermediate transport cylinder that receives the sheet from the reversing swing or reversing cylinder and passes it to the transfer cylinder.

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