Printing device

Abstract

A printing device (1) is provided with: a processing device (27); a processing cylinder (21) which conveys a sheet (4) to a position where printing is performed by the processing device (27); a pre-printing processing device (25) which is disposed on the upstream side of the processing cylinder (21); a pre-printing conveyance device (16) which conveys the sheet (4) to a position where pre-printing processing is performed by the pre-printing processing device (25), and which passes this sheet (4) to the processing cylinder (21); a conveyance mechanism (26) which passes the post-printing sheet (4) to a device in the next step; a reversing cylinder (45) which reverses the front and back of the sheet (4) from the conveyance mechanism (26); and a post-reversal conveyance device (47) which conveys the sheet (4) having undergone the front / back reversal to the upstream side of the pre-printing processing device (25). According to this configuration, it is possible to perform an appropriate amount of pre-printing processing even on a sheet having undergone the front / back reversal.

Description

printing device

[0001] The present invention relates to a printing apparatus that includes a processing cylinder that holds and transports a sheet, and a processing device that performs processing, including printing, on the sheet on the processing cylinder.

[0002] An example of a conventional printing device equipped with an inkjet head is disclosed in Patent Document 1. The printing device disclosed in Patent Document 1 is equipped with a reversing swing device that turns over a printed sheet and returns it to the printing cylinder, making it possible to print on both sides of the sheet using the inkjet head. The reversing swing device is configured to swing toward the printing cylinder while gripping the trailing edge of the sheet on the upstream side in the sheet conveyance direction, and to hand the sheet over to the printing cylinder gripper device.

[0003] In this type of printing device, pre-processing is sometimes performed on the sheet to be printed. To perform pre-processing on the sheet, a pre-processing device is installed upstream of the inkjet head in the sheet transport direction, and pre-processing is performed on the sheet transported by the printing cylinder. In recent years, there has been a demand to increase the number of pre-processing steps to further improve print quality.

[0004] In order to perform pre-processing on a sheet being transported by a printing cylinder, a pre-processing device must be installed in the free space around the printing cylinder. However, increasing the number of pre-processing items increases the size of the pre-processing device, which creates the problem of not being able to install the pre-processing device in a position facing the printing cylinder. When printing on both sides of a sheet, it is possible that pre-processing dedicated to the front and back may be performed, which could result in insufficient pre-processing.

[0005] JP 2017-210337 A JP 2013-240987 A JP 5-16330 A

[0006] An object of the present invention is to provide a printing apparatus that can perform pre-printing processing on inverted sheets without excess or deficiency.

[0007] One aspect of the present invention is a printing device comprising: a processing device configured to perform processing including printing on a sheet; a processing cylinder configured to transport the sheet to a position where the processing is performed by the processing device; a pre-printing processing device arranged upstream of the processing cylinder in the sheet transport direction and configured to perform pre-printing processing on the sheet; a pre-printing transport device configured to transport the sheet to a position where the pre-printing processing is performed by the pre-printing processing device and to transport the sheet that has undergone the pre-printing processing to the processing cylinder; a transport mechanism configured to receive the sheet that has undergone processing including printing by the processing device from the processing cylinder and transport it to a device for the next process; a reversing cylinder configured to receive the sheet from the transport mechanism and reversing the sheet; and a post-reversal transport mechanism configured to receive the inverted sheet from the reversing cylinder and transport it upstream in the sheet transport direction of the pre-printing processing device.

[0008] The printing apparatus may further include a feeder device including a feeder board configured to feed the sheet to the pre-printing transport device. The pre-printing transport device may include a supply cylinder configured to receive the sheet from the feeder board. The post-reversal transport mechanism may include a post-reversal transport device configured to transport the inverted sheet to the supply cylinder. The post-reversal transport device may be configured by a chain-type transport device. The post-reversal transport device may also be configured using an odd number of transfer cylinders.

[0009] The printing apparatus may further include a feeder device including a feeder board configured to feed the sheet to the pre-printing processing device, and the post-reversal transport mechanism may be configured to transport the sheet, with its front and back inverted, to the feeder device.

[0010] The post-reversal transport mechanism may be configured to transport the sheet, the front and back of which have been reversed, to the feeder board.

[0011] The feeder board may include a first feeder board and a second feeder board disposed downstream of the first feeder board in the sheet conveying direction and spaced apart from the first feeder board. The post-reversal conveying mechanism may be configured to feed the sheet from below the first feeder board and the second feeder board through a gap between the first feeder board and the second feeder board to the second feeder board.

[0012] The feeder board may include a pressure guide that is disposed above the gap between the first feeder board and the second feeder board and that changes the conveying direction of a sheet fed through the gap from below to a direction along the second feeder board. The feeder board may include a suction roller that is disposed above the gap between the first feeder board and the second feeder board and that rotates while sucking a sheet that has reached the gap from below, thereby guiding the sheet to the downstream side of the second feeder board in the sheet conveying direction.

[0013] The post-reversal conveying mechanism may include a post-reversal conveying device that conveys the sheet from the reversal cylinder, and a nipping conveying belt that sandwiches the sheet conveyed by the post-reversal conveying device from both sides in the thickness direction and conveys it to the gap between the first feeder board and the second feeder board. The post-reversal conveying device may be configured by a chain-type conveying device. The post-reversal conveying device may also be configured using an odd number of transfer cylinders.

[0014] The reversing cylinder may include a gripping member configured to grip the rear end of the sheet located upstream in the sheet conveying direction, and the gripping member may be configured to pivot relative to the reversing cylinder about an axis parallel to the axis of the reversing cylinder.

[0015] In one aspect of the present invention, the preprinting processing device is installed upstream of the processing cylinder in the sheet transport direction and away from the processing cylinder. This makes it easy to increase the number of preprocessing items performed by the preprinting processing device. Furthermore, after the reversed sheet has had its back side preprocessed by the first preprinting processing device, it is transported to the processing cylinder and printed on the back side. Therefore, one aspect of the present invention provides a printing device that can perform the proper amount of preprinting processing on reversed sheets.

[0016] Fig. 1 is a side view showing a printing apparatus according to a first embodiment of the present invention. Fig. 2 is a side view showing the main parts of the printing apparatus shown in Fig. 1. Figs. 3A to 3C are schematic diagrams for explaining the operation of a reversing cylinder. Fig. 4 is a side view showing a printing apparatus according to a second embodiment of the present invention.

[0017] First Embodiment A printing apparatus according to a first embodiment of the present invention will be described with reference to FIGS. 1, 2, and 3A to 3C.

[0018] 1 conveys sheets 4 from a feeder section 2 located at the far right in FIG. 1 to a printing unit 3, where printing is performed on one or both sides of the sheets 4. The sheets 4 printed in the printing unit 3 are sent to a delivery section 5 and accumulated in a delivery pile 6.

[0019] The feeder section 2 (feeder device) includes a feeder pile 11 on which a large number of sheets 4 are stacked, a sucker 12 that picks up the topmost sheet 4 from the sheets 4 on the feeder pile 11, and a feeder board 13 that sends the sheet 4 picked up by the sucker 12 to a supply cylinder 17 of a pre-printing transport device 16 of the printing unit 3, which will be described later.

[0020] The sucker 12 is connected to an intermittent feed valve 14 and operates in either a mode in which the sheet 4 is continuously fed or a mode in which the sheet 4 is intermittently fed. When printing is to be performed on only the front side of the sheet 4, the sucker 12 continuously feeds the sheet 4 to the feeder board 13. On the other hand, when printing is to be performed on both the front and back sides of the sheet 4, the sucker 12 intermittently feeds the sheet 4 to the feeder board 13.

[0021] The feeder board 13 conveys the sheet 4 by a rotating conveyor belt (not shown). The conveyor belt is wound around a drive pulley (not shown) and a driven pulley (not shown). A front stop (not shown) is provided near the end of the feeder board 13 on the downstream side in the sheet conveyance direction. This front stop is used to align the sheet 4 in the conveyance direction. Horizontal pins (not shown) are provided on both sides of the front stop to adjust the widthwise registration of the sheet 4.

[0022] Between the feeder board 13 and the pre-printing transport device 16, a swing device 15 is provided to transport the sheet 4 fed by the feeder board 13 to a supply cylinder 17 of the pre-printing transport device 16 of the printing unit 3.

[0023] The printing unit 3 includes a processing device 27 that performs processing including printing on the sheet 4, a processing cylinder 21 that adsorbs and transports the sheet 4 to a position where processing is performed by the processing device 27, a first pre-printing processing device 25 that is arranged upstream of the processing cylinder 21 in the sheet transport direction and performs pre-printing processing on the sheet 4, a pre-printing transport device 16 that transports the sheet 4 to a position where pre-printing processing is performed by the first pre-printing processing device 25 and sends the pre-printing processed sheet 4 to the processing cylinder 21, and a transport mechanism 26 that receives the sheet 4 that has been processed including printing by the processing device 27 from the processing cylinder 21 and sends it to the device for the next process.

[0024] The pre-printing transport device 16 is configured to transport the sheet 4 to the processing cylinder 21 using a supply cylinder 17, a first transfer cylinder 18, and a second transfer cylinder 19. The supply cylinder 17, the first transfer cylinder 18, and the second transfer cylinder 19 are each equipped with gripper devices 22, 23, and 24 (see FIG. 2), and these gripper devices 22 to 24 are used to transfer the sheet 4 to the adjacent cylinder. The gripper devices 22 to 24 grip and hold the leading end 4a of the sheet 4, which is the end on the downstream side in the sheet transport direction.

[0025] Of the three cylinders of the pre-printing transport device 16, a first pre-printing treatment device 25 is installed near the first transfer cylinder 18, which is located in the center. Although not shown in detail, the first pre-printing treatment device 25 is composed of devices that perform surface treatment and printing on the sheet 4 before printing, such as a pre-coat device, a corona treatment device, a spot color printing device, and a spot color drying lamp. The pre-coat device is a device that applies a coating to the sheet 4 before printing. The corona treatment device is a device that performs corona discharge treatment on the sheet 4 before printing. The spot color printing device is a device that prints special colors such as gold and silver. The spot color drying lamp dries the ink printed by the spot color printing device. The pre-printing transport device 16 transfers the sheet 4 that has been subjected to pre-printing treatment to the treatment cylinder 21 at the supply position P1.

[0026] The processing drum 21 is a triple-sized drum having a diameter three times that of a single drum, and has conveying surfaces 21a on which the sheet 4 is held at three locations in the rotational direction as shown in Figure 2. These three conveying surfaces 21a are formed on the outer peripheral surface of the processing drum 21, and divide the outer peripheral surface into thirds in the rotational direction as viewed from the axial direction of the processing drum 21. Peripheral cutouts 28 are provided between adjacent conveying surfaces 21a. Gripper devices 29 are provided within the peripheral cutouts 28. The gripper devices 29 are equivalent to the gripper devices 22 to 24 provided on the supply drum 17, first transfer drum 18, and second transfer drum 19 described above.

[0027] A second pre-printing treatment device 36, first, second, third and fourth inkjet heads 31, 32, 33 and 34, and an ink drying lamp 35 are arranged in this order around the treatment cylinder 21. The second pre-printing treatment device 36 performs a process that is the same as or different from the pre-treatment performed by the first pre-printing treatment device 25 described above.

[0028] The first to fourth inkjet heads 31 to 34 perform printing by ejecting ink droplets onto the sheet 4. Although not shown, each of these first to fourth inkjet heads 31 to 34 has a plurality of nozzles arranged in the axial direction of the processing cylinder 21 (a direction perpendicular to the paper surface of FIG. 2 ). Each of the first to fourth inkjet heads 31 to 34 also has a heater (not shown) that heats the ink to a predetermined temperature so that the ink droplets will adhere properly to the sheet 4.

[0029] The ink drying lamp 35 is used to harden the ink applied to the sheet 4 by the first to fourth inkjet heads 31 to 34. The ink drying lamp 35 irradiates the sheet 4 with infrared or ultraviolet light. The ink dries or hardens when irradiated with infrared or ultraviolet light.

[0030] In this embodiment, the second pre-printing treatment device 36, the first to fourth inkjet heads 31 to 34, and the ink drying lamp 35 constitute a treatment device 27 that performs treatments, including printing, on the sheet 4 on the treatment cylinder 21. Note that the second pre-printing treatment device 36 and the ink drying lamp 35 are not essential.

[0031] The transport mechanism 26 includes a discharge cylinder 41 that receives the sheet 4 from the processing cylinder 21 at a receiving position P2 located downstream of the first to fourth inkjet heads 31 to 34 in the sheet transport direction, and a pre-reversal double cylinder 42 that receives the sheet 4 from the discharge cylinder 41. The discharge cylinder 41 and the pre-reversal double cylinder 42 are respectively equipped with a gripper device 43 and a gripper device 44 for transferring the sheet 4 (see FIG. 2). These gripper devices 43, 44 are equivalent to the gripper devices 22 to 24 provided on the supply cylinder 17, first transfer cylinder 18, and second transfer cylinder 19 described above.

[0032] Of the sheets 4 received by the discharge cylinder 41 at the receiving position P2, those to be printed on the back side also travel from the discharge cylinder 41 through a reversing path 47 consisting of a pre-reversal double cylinder 42, a reversing cylinder 45 and a post-reversal conveying device 46 (described later), and are returned upside down to the supply cylinder 17. On the other hand, those sheets 4 to be printed only on the front side and those printed on both sides travel from the discharge cylinder 41 through a discharge path 49 including a delivery belt 48, and are discharged to the delivery section 5.

[0033] The discharge drum 41 constitutes a sheet path sorting device that sorts the conveying path to either a reversal path 47 where the sheet 4 is reversed, or a discharge path 49 where the sheet 4 is discharged. This sheet path sorting device can be constructed using, for example, the technology disclosed in Patent Document 2. Patent Document 2 discloses a cam device that uses a cam to open and close the gripper device 43 of the discharge drum 41 and change the opening and closing timing of the gripper device 43 (the timing of delivery of the sheet 4). The cam device is configured so that the sheet 4 is delivered from the discharge drum 41 to either the gripper device 44 of the pre-reversal double drum 42 or a gripper device (not shown) that moves together with the delivery belt 48.

[0034] The delivery unit 5 has three functions. The first function is to accumulate printed sheets 4 from the transport mechanism 26 in a delivery pile 6. The second function is to extract samples. The third function is to transport the sheets 4 to the next process.

[0035] The reversing cylinder 45 rotates in synchronization with the cylinders 41 and 42 that constitute the conveying mechanism 26, receives the sheet 4 from the conveying mechanism 26, turns the sheet 4 over, and sends the turned-over sheet 4 to the post-reversing conveying device 46. This reversing cylinder 45 is equivalent to the turning drum disclosed in Patent Document 3, for example, and has a gripping member 51 that grips the rear end 4b of the sheet 4 that is located upstream in the conveying direction of the sheet 4 being conveyed by the pre-reversing double cylinder 42, as shown in Figures 3A to 3C. The gripping member 51 is rotatable relative to the reversing cylinder 45 around an axis parallel to the axis of the reversing cylinder 45.

[0036] The post-reversal conveying device 46 conveys the sheet 4 received from the reversing drum 45 to the supply drum 17. The post-reversal conveying device 46 is configured as a chain-type conveying device and includes a pair of chains 46a aligned in the axial direction of the reversing drum 45, a number of gripper rods (not shown) stretched between the chains 46a, and gripper devices (not shown) provided on each of the gripper rods. The chains 46a are disposed between the reversing drum 45 and the supply drum 17. Although not shown, the post-reversal conveying device 46 can also be configured using an odd number of transfer drums instead of the chain-type conveying devices. These transfer drums are similar to the supply drum 17, first transfer drum 18, second transfer drum 19, etc., which are equipped with gripper devices that convey and transfer the sheet 4.

[0037] The supply cylinder 17 constitutes the upstream end in the sheet transport direction of the first pre-printing transport device 16. Therefore, in this embodiment, the post-reversal transport device 46 that transports the sheet 4 to the supply cylinder 17 constitutes a post-reversal transport mechanism that receives the inverted sheet 4 from the reversal cylinder 45 and transports it upstream in the sheet transport direction of the first pre-printing processing device 16.

[0038] The reversal of the sheet 4 will be described with reference to Figures 3A to 3C. The sheet 4 is conveyed by the pre-reversal doubler cylinder 42 with the printed surface 4c exposed outside the pre-reversal doubler cylinder 42. As shown in Figure 3A, when the trailing end 4b of the sheet 4 passes between the pre-reversal doubler cylinder 42 and the reversal cylinder 45, the gripping member 51 of the reversal cylinder 45 grips and holds the trailing end 4b of the sheet 4. As the reversal cylinder 45 rotates in this state, the sheet 4 is wound onto the reversal cylinder 45 with the trailing end 4b of the sheet 4 positioned downstream in the conveyance direction, as shown in Figures 3B to 3C. The sheet 4 is then passed from the reversal cylinder 45 to the post-reversal conveying device 46, and then returned from the post-reversal conveying device 46 to the supply cylinder 17.

[0039] When the sheet 4 is conveyed by the supply cylinder 17, the front surface 4c of the sheet 4 is exposed to the outside of the supply cylinder 17. Therefore, the sheet 4 conveyed through the reversing path 47 is transferred from the supply cylinder 17 to the first transfer cylinder 18 in an inverted state, and while being conveyed by the first transfer cylinder 18, the back surface is also subjected to pre-printing processing by the first pre-printing processing device 25.

[0040] In the printing apparatus 1 configured in this manner, the first preprinting processing device 25 is installed at a location upstream of the processing cylinder 21 in the sheet transport direction, which alleviates space constraints and makes it easy to increase the number of preprocessing items performed by the first preprinting processing device 25. Furthermore, after the reverse side of the sheet 4 has been preprocessed by the first preprinting processing device 25, the sheet 4 is transported to the processing cylinder 21 and printed on. Therefore, according to this embodiment, a printing apparatus can be provided that can perform just the right amount of preprinting processing on reversed sheets 4.

[0041] In this embodiment, the printing apparatus 1 includes a feeder unit 2 that supplies sheets 4 via a feeder board 13. The upstream end of the pre-printing transport device 16 in the transport direction is configured as a supply cylinder 17 that receives the sheets 4 sent by the feeder board 13. The supply cylinder 17 is also located upstream of a first pre-printing processing device 25 to which the inverted sheets 4 are transported. Therefore, the back side of the sheet 4 is also subjected to pre-printing processing by the first pre-printing processing device 25 in the same manner as the front side.

[0042] Second Embodiment The printing apparatus 1 described above is configured to return the inverted sheet 4 to the supply cylinder 17. However, in order to subject the inverted sheet 4 to preprocessing by the first preprinting processing device 25, the inverted sheet 4 may be returned to the feeder unit 2 as shown in Figure 4. In Figure 4, elements that are the same as or equivalent to elements shown in Figures 1 to 3C are designated by the same reference numerals, and detailed description thereof will be omitted.

[0043] The feeder section 2 of the printing device 61 shown in Figure 4 is configured so that sheets 4 can be supplied from below to the middle of the feeder board 13. The feeder board 13 is configured with a first feeder board 13a and a second feeder board 13b that is positioned downstream of the first feeder board 13a in the sheet transport direction and spaced apart from the first feeder board 13a. The gap between the first feeder board 13a and the second feeder board 13b forms a dividing section 62 that divides the feeder board 13 into an upstream side and a downstream side in the sheet transport direction.

[0044] A pressure guide 63 and a suction roller 64 are disposed above the dividing section 62. The pressure guide 63 changes the conveying direction of the sheet 4 fed from below through the dividing section 62 to a direction along the feeder board 13 (particularly, the second feeder board 13b). The suction roller 64 rotates while sucking the sheet 4 fed from below to the dividing section 62 near the dividing section 62, and guides the sheet 4 downstream in the sheet conveying direction of the feeder board 13 (particularly, the second feeder board 13b).

[0045] A pair of nipping conveying belts 65, 66 and the downstream end of the post-reversal conveying device 46 in the sheet conveying direction are disposed below the dividing unit 62. The pair of nipping conveying belts 65, 66 rotate in opposite directions to each other, sandwich the sheet 4 from both sides in the thickness direction, and convey it from the end of the post-reversal conveying device 46 to the dividing unit 62.

[0046] In the printing device 61 of this embodiment, the sheet 4 that has been inverted on the reversing cylinder 45 is chain-conveyed by the post-reversal conveying device 46 and sent from the downstream end of the post-reversal conveying device 46 in the conveying direction to between a pair of nip conveying belts 65, 66. The sheet 4 inserted between the nip conveying belts 65, 66 is sandwiched between the rotating nip conveying belts 65, 66 and conveyed to the dividing section 62. The sheet 4 that has reached the dividing section 62 is guided into the second feeder board 13b by the pressure guide 63 and suction roller 64.

[0047] In this embodiment as well, a registration device such as a front stop and side pins (not shown) is provided downstream in the sheet conveying direction of the feeder board 13 (second feeder board 13b). Therefore, the sheet 4 sent to the downstream end of the feeder board 13 in the sheet conveying direction is supplied from the swing device 15 to the supply cylinder 17 in a register-adjusted state.

[0048] Therefore, in this embodiment as well, it is possible to perform pre-printing processing on the inverted sheet 4 without excess or deficiency.

[0049] In this embodiment, a post-inversion conveying device 47 that conveys the inverted sheet 4 from the inversion drum 45, and clamping conveying belts 65, 66 that clamp the sheet 4 conveyed by the post-inversion conveying device 47 on both sides in the thickness direction and convey it to the dividing section 62 constitute a post-inversion conveying mechanism that conveys the sheet 4 from the inversion drum 45 to the feeder board 13 of the feeder section 2.

[0050] 1, 61...conveying device, 2...feeder section (feeder device), 4...sheet, 13...feeder board, 16...pre-printing conveying device, 17...supply cylinder, 21...processing cylinder, 25...first pre-printing processing device (pre-printing processing device), 26...conveying mechanism, 27...processing device, 45...reversing cylinder.

Claims

1. A printing apparatus comprising: a processing device configured to perform a process including printing on a sheet; a processing cylinder configured to convey the sheet to a position where the process by the processing device is performed; a pre-printing processing device disposed upstream of the processing cylinder in the sheet conveyance direction and configured to perform a pre-printing process on the sheet; a pre-printing conveyance device configured to convey the sheet to a position where the pre-printing process by the pre-printing processing device is performed and to send the sheet on which the pre-printing process has been performed to the processing cylinder; a conveyance mechanism configured to receive the sheet on which the process including printing by the processing device has been performed from the processing cylinder and send it to a device in the next step; a reversing cylinder configured to receive the sheet from the conveyance mechanism and reverse the front and back of the sheet; and a post-reversal conveyance mechanism configured to receive the sheet with the front and back reversed from the reversing cylinder and convey it upstream of the pre-printing processing device in the sheet conveyance direction.

2. The printing apparatus according to claim 1, further comprising a feeder device including a feeder board configured to send the sheet to the pre-printing conveyance device, wherein the pre-printing conveyance device includes a supply cylinder configured to receive the sheet from the feeder board, and the post-reversal conveyance mechanism includes a post-reversal conveyance device configured to convey the sheet with the front and back reversed to the supply cylinder.

3. The printing apparatus according to claim 1, further comprising a feeder device including a feeder board configured to send the sheet to the pre-printing processing device, wherein the post-reversal conveyance mechanism is configured to convey the sheet with the front and back reversed to the feeder device.

4. The printing apparatus according to claim 3, wherein the post-reversal conveyance mechanism is configured to convey the sheet with the front and back reversed to the feeder board.

5. The feeder board includes a first feeder board and a second feeder board disposed downstream of the first feeder board in the sheet conveyance direction and separated from the first feeder board. The post-inversion conveyance mechanism is configured to send the sheet from below the first feeder board and the second feeder board through a gap between the first feeder board and the second feeder board to the second feeder board. The printing apparatus according to claim 4.

6. The inversion cylinder includes a grip member configured to hold the rear end of the sheet located upstream in the sheet conveyance direction. The grip member is configured to pivot with respect to the inversion cylinder about an axis parallel to the axis of the inversion cylinder. The printing apparatus according to any one of claims 1 to 5.

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