Sheet handling apparatus

Abstract

The present sheet processing apparatus (1) is provided with: a printing cylinder (33) that conveys a sheet (S1) while the sheet is clamped by a gripping device (33A-33C) at a leading end of the sheet; a processing device (34) that faces a peripheral surface of the printing cylinder (33) and processes a surface of the sheet (S1) conveyed by the printing cylinder (33); a standby unit (52) that holds the processed sheet (S1) in a standby state; and a return cylinder (40) that conveys a trailing end of the sheet (S1) held in the standby state in the standby unit (52) to the gripping device (33A-33C) of the printing cylinder (33) so that the processed surface of the sheet (S1) contacts the peripheral surface of the printing cylinder (33). As a result, a sheet processing apparatus (1) having a simpler and more compact configuration can be realized compared to before.

Description

Technical Field

[0001] The present invention relates to a sheet processing apparatus having a flipping mechanism for flipping the front and back sides of a sheet. Background Technology

[0002] A sheet-feed rotary printing press exists, comprising a sheet mechanism for flipping the sheet after printing on its front side so as to print on the back side of the sheet. The sheet-feed rotary printing press includes a flipping mechanism for flipping the sheet between adjacent printing units, and is capable of performing both single-sided and double-sided printing.

[0003] In the sheet-feed rotary printing press disclosed in Patent Document 1, the flipping mechanism includes a conveyor roller (Patent Document 1). Figure 4 Reference numeral 17 in the figure) and the impression cylinder (Patent Document 1) Figure 4 (See reference numeral 16 in the attached figure). When performing double-sided printing, the rear edge of the conveyed sheet is held by the impression cylinder while its front edge is held by the conveying cylinder, allowing the sheet to be conveyed even when its conveying direction is changed.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: JP H03-080108 B Summary of the Invention

[0007] [Technical Issues]

[0008] However, in the sheet-feed rotary printing press disclosed in Patent Document 1, the configurations for printing the front and back sides are separate, and the entire device is relatively long in a straight line, which leads to the problem of increased size.

[0009] The purpose of this invention is to provide a sheet processing apparatus with a simpler and more compact configuration than the prior art.

[0010] [Technical Solution]

[0011] One aspect of the present invention relates to a sheet processing apparatus, the sheet processing apparatus comprising: a first roller including a first gripping device configured to grip an end of a sheet in a top-to-bottom direction and configured to convey the sheet while the end is gripped by the first gripping device; a processing device disposed outside the first roller so as to face the peripheral surface of the first roller and configured to perform surface processing on the sheet conveyed by the first roller; a discharge device for discharging the processed sheet; and a standby unit configured to receive the processed sheet from a first end of the first gripping device. The system receives and holds the sheet in a standby state, the first end of which is the end gripped by the first gripping device; a sorting mechanism configured to selectively sort the sheet from the first roller to a discharge device or a standby section; and a flipping device including a second gripping device configured to grip the second end of the sheet waiting in the standby section, the second end being the end not gripped by the first gripping device in the top-to-bottom direction, and the second gripping device configured to convey the second end of the sheet to the first gripping device on the first roller, such that the surface on which the processing device performs processing contacts the peripheral surface of the first roller. With this configuration, the number of rollers used can be reduced to a number corresponding to the use of a standby section and a conveying section, the standby section being the one that holds the sheet in a standby state, and the conveying section being the one that conveys the sheet from the first roller to the standby section. Furthermore, the first roller can be used again to process the flipped sheet. Therefore, the configuration can be simplified, enabling a sheet processing apparatus with a simpler and more compact configuration than the prior art.

[0012] The sheet processing equipment may further include a first adjusting device configured to adjust the position of the second end of the sheet in the standby section. By adjusting the position of the sheet in the standby section using the first adjusting device, the sheet can be reliably flipped according to the sheet size even if the sheet size changes.

[0013] The standby section may include a belt configured to transport a sheet. An embodiment of the first adjustment device includes a stop configured such that a first end of the sheet on the belt contacts the stop. This allows the sheet to be transported using a belt and the sheet's position in the standby section to be adjusted using the stop.

[0014] The stop can move in the conveying direction of the sheet.

[0015] When the belt approaches the stop, the belt can tilt downwards.

[0016] The standby section may also include a guide cover, which is configured to face the surface of the belt on which the sheet is placed.

[0017] Another embodiment of the first adjusting device includes: a pair of rollers configured to clamp a sheet on two surfaces of the sheet, the pair of rollers having a rotation axis extending in a direction perpendicular to the conveying direction of the sheet; a motor configured to rotate at least one of the rollers; and a controller configured to control the motor according to the size of the sheet. By controlling the motor for rotating the pair of rollers clamping the sheet, the position of the sheet in the standby section is adjusted, and the sheet can be reliably flipped according to the sheet size even if the sheet size changes.

[0018] This embodiment may also include a first sensor configured to detect the length of the sheet in the conveying direction and output the result to the controller.

[0019] The sheet processing equipment may further include a second adjusting device configured to adjust the position of a side edge portion of the sheet in the width direction before it is gripped by a second gripping device in the standby section. This enables registration adjustment in the width direction to process the other surface of the flipped sheet.

[0020] One embodiment of the second adjusting device includes: a pair of rollers configured to move toward and away from each other and having a rotation axis extending in a direction parallel to the conveying direction of the sheet; a motor configured to rotate the pair of rollers while the pair of rollers clamp two surfaces of the sheet; and a side guide configured such that a side edge of the sheet moving in a direction perpendicular to the conveying direction by rotating the pair of rollers contacts the side guide.

[0021] Another embodiment of the second adjustment device includes: a pair of rollers configured to clamp two surfaces of a sheet and having a rotation axis extending in a direction perpendicular to the conveying direction of the sheet; an adjustment mechanism configured to adjust the axial position of the pair of rollers; and a controller configured to control the adjustment mechanism according to the position of the side edges of the sheet.

[0022] This embodiment may also include a second sensor configured to detect the position of the side edge of the sheet.

[0023] The sheet handling equipment may further include: a second roller facing the first roller and including a third gripping device configured to receive processed sheets from the first roller, the second roller being configured to convey the sheets gripped by the third gripping device; and a pre-rotating roller facing the second roller and including a fourth gripping device configured to receive sheets from the second roller, the pre-rotating roller being configured to convey the sheets gripped by the fourth gripping device. A sorting mechanism may be constructed from the second roller. A belt may be configured to receive the sheets conveyed via the pre-rotating roller. Using this configuration, sheet conveying from the second roller to a standby section is performed via the pre-rotating roller and the belt, and since the belt also serves as a standby section, the configuration of the sheet handling equipment can be simplified.

[0024] The flipping device may include a guide member configured to lift the second end of a sheet waiting in the standby section and convey the sheet to a second gripping device. By lifting the second end of the sheet in the standby section, the sheet can be reliably conveyed to the second gripping device of the flipping device.

[0025] The standby section may include a belt configured to convey sheet material. The flipping device may include: an upper roller disposed above the belt; and a lower roller disposed below the belt, movable in a vertical direction, and configured to lift the sheet material together with the belt and clamp the sheet material together with the upper roller. The upper and lower rollers are configured to rotate in the direction in which the sheet material moves toward the second gripping device.

[0026] The upper and lower rollers can be positioned at positions corresponding to the second end of the sheet that is waiting in the standby section.

[0027] The flipping device may also include a return roller, which includes a second gripping device and contacts the first roller.

[0028] The flipping device may also include a guide disposed above the belt and configured to guide the sheet, whose second end has been lifted by the lower roller, to the second gripping device.

[0029] The guide may include an upper guide and a lower guide, which include two plate-like members facing each other.

[0030] As the belt moves away from the positions of the upper and lower rollers, it can tilt downwards.

[0031] The sheet handling equipment may further include: a second roller facing the first roller and including a third gripping device configured to receive processed sheet material from the first roller, the second roller being configured to convey the sheet material gripped by the third gripping device; a first guide extending from the second roller to a discharge device; and a second guide branching from the first guide and extending to a belt. The belt may be configured to receive the sheet material conveyed by the second guide.

[0032] The first guide member may include an upper guide member and a lower guide member, which each include two plate-like members facing each other. The second guide member may include an upper guide member and a lower guide member, which each include two plate-like members facing each other. The second guide member may include a semi-circular portion.

[0033] The first guide may include a first roller configured to convey sheet material from the second roller to a discharge device. The second guide may include a second roller configured to convey sheet material from the second roller to a belt.

[0034] An embodiment of the sorting mechanism is a second roller. In this case, the sheet can be sorted into either the first guide or the second guide while being released by the third gripping device of the second roller. When the second guide branches downward from the first guide, the sheet can be sorted into the second guide by releasing it through the third gripping device before the second end of the sheet gripped by the third gripping device passes the last branch point between the first and second guides. Simultaneously, the sheet can be sorted into the first guide by releasing it through the third gripping device after the second end of the sheet gripped by the third gripping device passes the branch point between the first and second guides.

[0035] Another embodiment of the sorting mechanism is a plate disposed at the branch point between the first guide and the second guide, the plate being configured to selectively block either the first guide or the second guide.

[0036] [Beneficial Effects]

[0037] According to one aspect of the invention, the number of rollers used can be reduced by an amount corresponding to the use of a standby section to hold the sheet in a standby state and a conveying section to transport the sheet from the first roller to the standby section. Furthermore, the first roller can be used again to process the flipped sheet. Therefore, the configuration can be simplified, enabling the realization of a sheet processing apparatus with a simpler and more compact configuration than that of the prior art. Attached Figure Description

[0038] Figure 1This is a side view showing the overall configuration of a digital printing apparatus according to a first embodiment of a sheet processing apparatus according to the present invention.

[0039] Figure 2 It is an enlarged side view of the area near the return roller and guide roller.

[0040] Figure 3 This is a side view showing the sheet conveying process (1).

[0041] Figure 4 This is a side view showing the sheet conveying process (2).

[0042] Figure 5 This is a side view showing the sheet conveying process (3).

[0043] Figure 6 This is a side view showing the sheet conveying process (4).

[0044] Figure 7 This is a side view showing the sheet conveying process (5).

[0045] Figure 8 This is a side view showing the sheet conveying process (6).

[0046] Figure 9 This is a side view showing the sheet conveying process (7).

[0047] Figure 10 This is a side view showing the overall configuration of a digital printing apparatus according to a second embodiment of the sheet processing apparatus according to the present invention.

[0048] Figure 11 This is a side view showing the configuration of the upper and lower guides.

[0049] Figure 12 This is a side view showing the sheet conveying process (1).

[0050] Figure 13 This is a side view showing the sheet conveying process (2).

[0051] Figure 14 This is a side view showing the sheet conveying process (3).

[0052] Figure 15 This is a side view showing the sheet conveying process (4).

[0053] Figure 16 This is a side view showing the sheet conveying process (5).

[0054] Figure 17 This is a side view showing the sheet conveying process (6).

[0055] Figure 18 This is a side view showing the sheet conveying process (7).

[0056] Figure 19 This is a side view showing a pair of clamping rollers that form part of the first and second adjusting devices.

[0057] Figure 20 This is a block diagram showing another partial configuration of the first and second regulating devices.

[0058] Figure 21A This is a side view showing another mechanism of the upper and lower guides.

[0059] Figure 21B This is a side view showing another mechanism of the upper and lower guides. Detailed Implementation

[0060] Embodiments of the present invention will be described below with reference to the accompanying drawings.

[0061] [First Embodiment]

[0062] Figure 1 The configuration of a digital printing apparatus 1 according to a first embodiment of the sheet processing apparatus of the present invention is shown. The digital printing apparatus 1 includes a sheet feeder 2, a digital printing unit 3, and a sheet conveying unit 4 serving as an ejection device.

[0063] With the aid of a sheet picker 23, which serves as a sheet supply device, the sheet feeder 2 of the digital printing apparatus 1 picks up a single sheet S1 from the top of the sheet stack 22 stacked on the stacking plate 21, and moves the sheet S1 by the sheet picker 23 and places it on the feeder plate FB, thereby sequentially supplying the sheet S1 to the digital printing unit 3. The sheet picker 23 is connected to a negative pressure source (not shown), and while attracting the sheet S1 from the sheet stack 22 by the first picker 23A and the second picker 23B, it conveys the sheet S1 to the feeder plate FB by horizontal movement, and then releases the pick-up.

[0064] Here, when the single-sided printing mode for printing only the front side of sheet S1 is selected, according to commands from a controller having a central processing unit (CPU) arrangement (not shown), sheet feeder 2 continuously picks up sheet S1 at predetermined time intervals via sheet picker 23 and conveys sheet S1 to feeder plate FB to perform continuous sheet feeding. Simultaneously, when the double-sided printing mode (printing not only the front side of sheet S1 but also the back side) is selected, compared to continuous sheet feeding via sheet picker 23 according to commands from the controller (not shown), sheet feeder 2 intermittently picks up sheet S1 at intervals and conveys sheet S1 to feeder plate FB to perform intermittent sheet feeding. In this way, digital printing equipment 1 can continuously feed sheet S1 to digital printing unit one sheet at a time from sheet feeder 2, or can feed sheet S1 intermittently.

[0065] The sheet S1 fed to the feeder plate FB is aligned in the top-bottom direction and the left-right direction via a registration device (not shown) at the front end FB1 of the feeder plate.

[0066] The digital printing unit 3 of the digital printing equipment 1 includes: a oscillating device 31 for receiving a sheet S1 supplied from a feeder plate FB by a clamp (not shown); a feed roller 32 for re-clamping a first end of the sheet S1 supplied by the oscillating device 31 in the top-bottom direction (length direction) by means of a gripping device 32A, and then conveying the first end to a printing roller 33 serving as a first roller; and a printing roller 33 for use by any one of three first gripping devices 33A, 33B, and 33C. The printing roller 33 is used to re-clamp the first end of the sheet S1 supplied from the feed roller 32 and rotates while absorbing the entire surface of the sheet S1 onto its peripheral surface to transport the sheet S1; a four-color inkjet nozzle unit 34, which serves as a processing device, is disposed downstream of the feed roller 32 in the transport direction and faces the peripheral surface of the printing roller 33; and a transfer roller 36, which serves as a second roller, is disposed downstream of the inkjet nozzle unit 34 in the transport direction and faces the printing roller 33.

[0067] The feed roller 32 has a gripping device 32A, and the feed roller 32 is sized to convey a sheet S1 on its peripheral surface. However, the printing roller 33 is a roller of three times the size with three first gripping devices 33A, 33B and 33C arranged at regular angular intervals. The circumference of the roller is equal to that of the three largest sheets S1 connected together.

[0068] The printing roller 33 has a plurality of suction holes (not shown) formed at predetermined intervals above its entire peripheral surface, and the printing roller 33 has the following structure: while absorbing and holding the entire surface of the sheet S1, it performs suction by passing through these suction holes from the inside, and this structure is used to transport the sheet S1.

[0069] In the order of the first gripping devices 33A, 33B and 33C of the printing cylinder 33, the printing cylinder 33 re-grips the sheets S1 supplied by the gripping device 32A of the feed cylinder 32 one after another, and sequentially feeds the sheets S1 to the inkjet nozzle unit 34 by rotating in the direction of the arrow (counterclockwise).

[0070] The inkjet nozzle unit 34 has black inkjet nozzle head 34A, cyan inkjet nozzle head 34B, magenta inkjet nozzle head 34C and yellow inkjet nozzle head 34D arranged sequentially in the conveying direction and facing downstream. It performs digital printing processing on the sheet S1 by spraying finely atomized ink toward the peripheral surface of the conveyed sheet S1 and simultaneously being completely absorbed onto the peripheral surface of the printing cylinder 33.

[0071] The gap between the inkjet nozzle heads 34A to 34D (corresponding to each color of the inkjet nozzle unit 34) and the sheet S1 that is fully picked up onto the peripheral surface of the printing cylinder 33 must be set to an extremely small minimum gap in order to maintain a predetermined level of print quality. Therefore, by fully picking up the sheet S1 onto its peripheral surface, the printing cylinder 33 maintains the gap between the inkjet nozzle heads 34A to 34D and the sheet S1 picked up onto the printing cylinder 33 at an extremely small minimum gap.

[0072] In the digital printing unit, a transfer roller 36, which serves as a sorting mechanism and faces the printing roller 33, is positioned downstream of the printing roller 33 in the conveying direction. A "belt-conveyor" type conveyor belt DB, which is used to transport the sheet S1 to the sheet conveying unit 4, is positioned downstream of the transfer roller 36 in the conveying direction. A pre-rotating roller 39, which faces the transfer roller 36, is positioned downstream of the transfer roller 36 in the conveying direction.

[0073] Therefore, when the single-sided printing mode is selected, the transfer roller 36 in the digital printing unit 3 re-grabs the sheet S1 gripped by any one of the gripping devices 33A to 33C of the printing roller 33, and completely sucks it onto the peripheral surface of the printing roller 33 by the third gripping device 36A of the transfer roller 36, and then places it on the conveyor belt DB, thereby sequentially discharging the sheet S1 to the subsequent sheet conveying unit 4 via the conveyor belt DB.

[0074] The sheet conveying unit 4 stacks the sheet S1 conveyed via the conveyor belt DB onto the stacking plate 41 and discharges the sheet S1 after digital printing.

[0075] Meanwhile, when the double-sided printing mode for printing the back side of the sheet S1 is selected, the digital printing unit 3 performs digital printing processing on the front side of the sheet S1 through the printing roller 33 and the inkjet nozzle unit 34, and then, instead of conveying the sheet S1 to the conveyor belt DB through the third gripping device 36A of the transfer roller 36, the digital printing unit 3 re-grips the first end of the sheet S1 from the third gripping device 36A of the transfer roller 36 to the fourth gripping device 39A of the pre-flipping roller 39.

[0076] The pre-reversing roller 39 re-clamps the first end of the sheet S1 from the conveyor roller 36 via the fourth gripping device 39A, and then conveys the sheet S1 in the conveying direction to the belt 64 located downstream of the pre-reversing roller 39. It should be noted that in the digital printing unit 3, the return roller 40 facing the printing roller 33 is located downstream of the conveyor roller 36 in the conveying direction.

[0077] Next, the configuration of belt 64 will be described. Belt 64 has one end that contacts the pre-rotating roller 39 and another end that forms the standby section 52, and belt 64 is wound around drive rollers 62 and 68 provided at the two ends, and around driven roller 63 provided near drive roller 62, and belt 64 is configured to receive sheet S1 conveyed from pre-rotating roller 39 thereon.

[0078] On the belt 64, a thin, plate-shaped guide cover 61 is configured to be substantially parallel to the belt 64 with a small gap, so as to face the placement surface on which the sheet S1 is to be placed. This allows the belt 64 to convey the sheet S1 carried on the belt 64 via drive rollers 62 and 68, while the guide cover 61 is used to suppress the vibration of the sheet S1.

[0079] Furthermore, a stop 67 is attached near the drive roller 68, which stops the sheet S1 by contacting the first end of the sheet S1 conveyed by the belt 64. Therefore, the sheet S1 conveyed by the belt 64 eventually contacts the stop 67 and remains in standby position 52. At this time, as the drive rollers 62 and 68 continue to rotate, the sheet S1 slides on the belt 64 and continues to be pressed against the stop 67 at the first end (front edge) of the sheet S1. As a result, registration adjustment of the sheet S1 in the top-to-bottom direction is performed.

[0080] It should be noted that, in the conveying direction of the sheet, the stop 67 is movably attached to the belt 64 according to the length of the sheet S1. That is, the longer the sheet S1, the closer the stop 67 is attached to the drive roller 68; conversely, the shorter the sheet S1, the closer the stop 67 is attached to the return roller 40. Therefore, the standby position of the sheet S1 can be adjusted by the attachment position of the stop 67.

[0081] At this point, the registration adjustment of sheet S1 in the left-right direction (width direction) is performed by a transverse pin device 67A, which serves as a second adjustment device, disposed between stop 67 and upper guide 66A (described later). Although not shown in detail, the transverse pin device 67A includes a pair of rollers for selectively clamping one side edge of sheet S1 in the left-right direction, and a side guide positioned at the side of sheet S1. The pair of rollers rotate about a rotation axis extending in a direction parallel to the conveying direction of sheet S1 and are configured to move toward and away from each other. More specifically, the pair of rollers separate just before sheet S1 arrives, clamping sheet S1 in the middle as it enters between the rollers, and are rotated by a motor to advance sheet S1 toward the side guide. The side guide defines the position of the side edge of sheet S1. When the side edge of the sheet S1, which is driven by the pair of rollers and moves laterally, contacts the side guide, the registration amount of the sheet S1 in the left-right direction is adjusted.

[0082] In belt 64, when stop 67 inhibits the feeding of sheet S1, guide roller 65 is positioned at a location corresponding to the tail edge as the second end of sheet S1. Guide roller 65 has an upper drive roller 65A disposed above belt 64 and a lower driven roller 65B disposed below belt 64. When the feeding of sheet S1 described above is inhibited, the second end of sheet S1 is positioned between the upper drive roller 65A and the lower driven roller 65B.

[0083] Through holes are formed in the portions of the guide cover 61 corresponding to the upper drive roller 65A and the lower driven roller 65B. Therefore, the upper drive roller 65A and the lower driven roller 65B can convey the sheet S1 while clamping the sheet S1 together with the belt 61.

[0084] The lower driven roller 65B is configured such that, with the second end of the sheet S1 positioned between the upper drive roller 65A and the lower driven roller 65B of the guide roller 65, the lower driven roller 65B can move freely upward. This allows the entire guide roller 65 to be raised above the placement surface of the belt 64 while the second end of the sheet S1 is held between the upper drive roller 65A and the lower driven roller 65B, causing the second end of the sheet S1 to separate upward from the placement surface of the belt 64.

[0085] In practice, synchronized with the re-grip of the second end of the sheet S1 by the second gripping device 40A of the return roller 40, the lower driven roller 65B of the guide roller 65 moves upward to lift the rear edge of the sheet S1, and the upper drive roller 65A is used to clamp the rear edge of the sheet S1. The upper drive roller 65A is configured to rotate to convey the sheet S1 toward the second gripping device 40A of the return roller 40. At this time, when the lower driven roller 65 clamps the sheet S1, the upper drive roller 65A can start rotating from a stopped state, or it can be configured to rotate continuously. It should be noted that at this time, the drive rollers 62 and 68 can continue to rotate or can stop rotating.

[0086] As a result, Figure 2 As shown, the belt 64 guides the rear edge of the sheet S1, which is held between the upper drive roller 65A and the lower driven roller 65B, toward the return roller 40, and by inserting the rear edge of the sheet S1 between the upper guide 66A and the lower guide 66B, the rear edge of the sheet S1 is guided to the second gripping device 40A of the return roller 40 and is re-gripped by the second gripping device 40A.

[0087] The return roller 40 rotates clockwise in the direction of the arrow, while simultaneously holding the sheet S1 so that its rear edge is gripped by the second gripping device 40A, thereby conveying the sheet S1, which has been flipped from the front to the back, to the printing roller 33. By using the transfer roller 40, the flipped sheet S1, gripped by the second gripping device 40A, can be conveyed again from its rear edge to the printing roller 33, so that the surface on which the digital printing process has been performed on the printing roller 33 comes into contact with the peripheral surface of the printing roller 33.

[0088] In practice, in the digital printing unit 3, when the second gripping device 40A of the return roller 40 faces any one of the first gripping devices 33A to 33C of the printing roller 33, the sheet S1 is re-gripped from the return roller 40 to the printing roller 33, thereby conveying the flipped sheet S1 from the return roller 40 to the printing roller 33.

[0089] Therefore, the digital printing unit 3 re-feeds the sheet S1, which is re-grabbed by any one of the first gripping devices 33A to 33C of the printing roller 33, to the inkjet nozzle unit 34, while absorbing its entire surface onto the peripheral surface, performing digital printing on the back side of the sheet S1, and then conveying it to the conveyor belt DB via the transfer roller 36, thereby completing the double-sided printing process.

[0090] It should be noted that the belt assembly 60 consists of drive rollers 62 and 68, driven roller 63, and belt 64. In the entire region of belt 64 from drive roller 62 to drive roller 68, the conveying section 51 consists of the belt portion from drive roller 62 to guide roller 65 and the pre-rotating roller 39. Furthermore, in the entire region of belt 64 from drive roller 62 to drive roller 68, the standby section 52 consists of the portion of belt from guide roller 65 to drive roller 68. This standby section 52 is used to temporarily hold the sheet S1 in standby mode for conveying the sheet S1 from return roller 40 to printing roller 33. Here, the conveying section 51 and standby section 52 are defined only for convenience and are not necessarily limited thereto. For example, the conveying section 51 may be limited to not including the pre-rotating roller 39.

[0091] As described above, the digital printing press 1 of this embodiment includes: a printing cylinder 33, which serves as a first cylinder and includes first gripping devices 33A to 33C configured to grip the end of a sheet S1 in a top-to-bottom direction, and the printing cylinder 33 is configured to convey the sheet S1 when the end of the sheet S1 is gripped by the first gripping devices 33A to 33C; an inkjet nozzle unit 34, which serves as a processing device, is disposed outside the printing cylinder 33 to face the peripheral surface of the printing cylinder 33, and the inkjet nozzle unit 34 is configured to perform processing on the surface of the sheet S1 conveyed by the printing cylinder 33; a sheet conveying unit 4, which serves as a discharge device and is configured to discharge the processed sheet S1; and a standby unit 52, which is configured to receive from the first end... The first end of the sheet S1 is the end gripped by the first gripping devices 33A to 33C; a sorting mechanism is configured to selectively sort the sheet S1 from the printing cylinder 33 to the sheet transport unit 4 or the standby section 52; and a flipping device includes a second gripping device 40A configured to grip the second end of the sheet S1 that is not gripped by the first gripping devices 33A to 33C in the top-bottom direction, and the second gripping device 40A is configured to convey the second end of the sheet S1 to the first gripping devices 33A to 33C of the printing cylinder 33, such that the surface on which the inkjet nozzle unit 34 has performed the treatment is in contact with the peripheral surface of the printing cylinder 33.

[0092] The digital printing press 1 also includes a first adjustment device configured to adjust the position of the second end of the sheet S1 in the standby section 52. The standby section 52 includes a belt 64 configured to transport the sheet S1, and the first adjustment device includes a stop 67 configured such that the first end of the sheet S1 on the belt 64 contacts the stop 67.

[0093] The digital printing press 1 also includes a transverse pin device 67 serving as a second adjustment device, which is configured to adjust the position of the side edge portion of the sheet S1 in the width direction before being gripped by the second gripping device 40A in the standby unit 52. The transverse pin device 67 includes: a pair of rollers configured to move toward and away from each other and having a rotation axis extending in a direction parallel to the conveying direction of the sheet; a motor configured to rotate the pair of rollers while the pair of rollers clamp the two surfaces of the sheet; and a side guide configured such that, by rotating the pair of rollers, the side edge of the sheet S1, which moves in a direction perpendicular to the conveying direction, contacts the side guide.

[0094] The digital printing press 1 further includes: a transfer roller 36, which serves as a second roller, faces the printing roller 33, and includes a third gripping device 36A configured to receive processed sheet S1 from the printing roller 33; the transfer roller 36 is configured to convey the sheet S1 gripped by the third gripping device 36A; and a pre-rotation roller 39, which faces the transfer roller 36 and includes a fourth gripping device 39A configured to receive sheet S1 from the transfer roller 36; the pre-rotation roller 39 is configured to convey the sheet S1 gripped by the fourth gripping device 39A. The sorting mechanism described above is constituted by the transfer roller 36. The belt 64 described above is configured to receive the sheet S1 conveyed by the pre-rotation roller 39.

[0095] The flipping device described above includes a guide member configured to lift the second end of the sheet S1 waiting in the waiting section 52 and convey the sheet S1 to the second gripping device 40A. The guide member includes a lower driven roller 65B, an upper guide 66A, and a lower guide 66B.

[0096] The flipping device described above includes: an upper drive roller 65A, which serves as an upper roller disposed above the belt 64; a lower driven roller 65B, which serves as a lower roller disposed below the belt 64, the lower driven roller 64 being movable in the vertical direction and configured to lift the sheet S1 together with the belt 64 and clamp the sheet S1 together with the upper drive roller 65A; a return roller 40, which includes the second gripping device 40A described above and faces the printing roller 33; and a guide, which is disposed above the belt 64 and configured to guide the sheet S1, whose second end has been lifted by the lower driven roller 65B, to the second gripping device 40A. The guide includes an upper guide 66A and a lower guide 66B, which each includes two plate-like members facing each other. The upper drive roller 65A and the lower driven roller 65B are configured to rotate in the direction in which the sheet S1 moves toward the second gripping device 40A (return roller 40). The upper drive roller 65A and the lower driven roller 65B are positioned at the second end position corresponding to the sheet S1 waiting in the standby section 52. The belt 64 tilts downward as it moves away from the upper drive roller 65A and the lower driven roller 65B.

[0097] Next, the operation of digital printing unit 3 will be described. When the double-sided printing mode is selected, as follows: Figure 3 As shown, the leading edge of the sheet S1 gripped by the gripping device 32A of the feed roller 32 is re-gripped by the first gripping device 33A of the printing roller 33, for example.

[0098] like Figure 4 As shown, the printing roller 33 rotates counterclockwise, so that the sheet S1 held by the first gripping device 33A is re-gripped by the third gripping device 36A of the transfer roller 36.

[0099] Then, as Figure 5 As shown, when the third gripping device 36A of the conveyor roller 36 and the fourth gripping device 39A of the pre-rotation roller 39 face each other, the sheet S1 is gripped again from the conveyor roller 36 to the pre-rotation roller 39. At the same time, the next new sheet S1, intermittently fed by the feed roller 32, is held by the first gripping device 33C of the printing roller 33.

[0100] like Figure 6 As shown, the sheet S1 held by the fourth gripping device 39A of the pre-rotating roller 39 is placed on the belt 64. At this time, the printing roller 33 picks up the next sheet S1 held by the first gripping device 33C onto its peripheral surface and transports the next sheet S1 earlier.

[0101] like Figure 7As shown, the sheet S1 placed on the belt 64 is conveyed to the standby section 52 below the lower guide 66B via the belt 64. The front edge of the sheet S1 contacts the stop 67, and registration adjustment is performed by activating the transverse pin device 67A.

[0102] like Figure 8 As shown, synchronized with the arrival of the second gripping device 40A of the return roller 40 for re-gripping, the lower driven roller 65B rises to lift the rear edge of the sheet S1, which is locked by the stop 67 of the standby section 52, above the conveyor belt 64, and clamps it using the upper drive roller 65A. The upper drive roller 65A rotates to convey the sheet S1 toward the second gripping device 40A of the return roller 40. The sheet S1 passes between the upper guide 66A and the lower guide 66B, the rear edge of the sheet S1 is gripped by the second gripping device 40A of the return roller 40, and then the sheet S1 is re-gripped from the second gripping device 40A of the return roller 40 to the first gripping device 33C of the printing roller 33.

[0103] In this case, such as Figure 9 As shown, during the stage where the sheet S1 is transferred from the return roller 40 to the printing roller 33, the printing roller 33 conveys the already flipped sheet S1 to the back side. Therefore, the back side of the sheet S1, which is the sheet S1 that has been retransmitted by the printing roller 33 that performed printing on the front side, can be digitally printed by the inkjet nozzle unit 34.

[0104] As described above, in the digital printing unit 3 of the digital printing equipment 1, the front side of the sheet material conveyed by the printing roller 33 is digitally printed by the inkjet nozzle unit 34, and then the sheet material S1 is conveyed to the belt 64 via the transfer roller 36 and the pre-flip roller 39. The sheet material S1 is conveyed to the transport section 51 and the standby section 52 via the belt 64. The end (front edge) of the sheet material S1 contacts the stop member 67 of the standby section 52, and the registration adjustment is performed by activating the transverse pin device 67A, that is, the position adjustment of the standby position of the sheet material S1.

[0105] Then, in sync with the second gripping device 40A of the return roller 40 approaching the rear edge of the sheet S1, the lower driven roller 65B rises to lift the rear edge of the sheet S1 above the conveyor belt 64 and clamp it using the upper drive roller, and the upper drive roller 65A of the guide roller 65 rotates to convey the sheet S1 toward the second gripping device 40A of the return roller 40.

[0106] As a result, the digital printing unit 3 can reliably guide the sheet S1 from the guide roller 65 to the second gripping device 40A of the return roller 40 via the upper guide 66A and the lower guide 66B, so that the second gripping device 40A grips the rear edge of the sheet S1 and re-grips the sheet S1 from the second gripping device 40A of the return roller 40 to the first gripping device 33A to the first gripping device 33C of the printing roller 33. Therefore, the sheet S1 can be fed back to the printing roller 33 while maintaining the registration adjustment state of the sheet S1 that has already been performed.

[0107] Therefore, with registration adjustment performed via the printing cylinder 33 and the inkjet nozzle section 34, the digital printing unit can perform digital printing processing on the back side of the sheet S1. This prevents misalignment between the printing results on the front and back sides, and improves the printing quality on both sides of the sheet S1.

[0108] Furthermore, the digital printing unit can also reuse the printing cylinder 33 and inkjet nozzle 34, which perform digital printing processing on the front side of the sheet S1, to perform digital printing processing on the back side of the sheet S1. Therefore, since the printing cylinder 33 and inkjet nozzle 34 can be shared for digital printing processing on both the front and back sides, double-sided printing of the sheet S1 can be performed with high precision without increasing the overall size of the equipment.

[0109] [Second Embodiment]

[0110] Figure 10 The configuration of a digital printing apparatus 100 according to a second embodiment of the sheet processing apparatus of the present invention is shown. Figure 10 In the middle, to and Figure 1 Components that are identical or corresponding to each other are given the same reference numerals, and descriptions thereof are omitted where appropriate.

[0111] The digital printing equipment 100 includes a sheet feeder 2, a digital printing unit 3, and a sheet conveying unit 4 serving as an ejection device. The digital printing equipment 100 and... Figure 1 The main difference in the digital printing equipment 1 shown is the configuration from the conveyor roller 36 to the return roller 40, namely the configuration of the conveyor section, the standby section, and the flipping device.

[0112] In the digital printing unit 3, the conveyor roller 36, which serves as a sorting mechanism and faces the printing roller 33, is positioned downstream of the printing roller 33 in the conveying direction, and the auxiliary roller 36B, which faces the conveyor roller 36, is positioned downstream of the conveyor roller 36 in the conveying direction.

[0113] Between the conveyor roller 36 and the auxiliary roller 36B, viewed from the side, there are upper guide members 71 and lower guide members 72, which are made of thin plates formed by horizontal straight lines, for conveying the sheet S1 conveyed by the conveyor roller 36 to the sheet conveying unit 4. It should be noted that in the digital printing unit 3, the return roller 40 facing the printing roller 33 is located downstream of the conveyor roller 36 in the conveying direction.

[0114] like Figure 11 As shown, the upper guide 84 and lower guide 85 are curved in a semi-circular shape, as can be seen from the side branch between the upper guide 71 and the lower guide 72. The upper guide 84 and lower guide 85 are disposed between the conveying roller 36 and the auxiliary roller 36B. While the sheet S1 is discharged into the sheet conveying unit 4 via the upper guide 71 and lower guide 72, the sheet S1 is also conveyed from the upper guide 71 and lower guide 72 to the conveying section 151 via the upper guide 84 and lower guide 85.

[0115] The upper guide 71 and the lower guide 72 are provided with clamping rollers 73A and 73B and clamping rollers 74A and 74B for conveying the sheet S1 from the transfer roller 36 to the sheet conveying unit 4 while the sheet S1 is clamped therein. Here, the clamping rollers 73B and 74B provided on the lower side are driven by a counterclockwise rotating motor (not shown), and the clamping rollers 73A and 74A facing the clamping rollers 73B and 74B are driven to rotate.

[0116] Through holes are formed in the upper guide 71 and the lower guide 72 at positions corresponding to the two pairs of clamping rollers (clamping rollers 73A and 73B, clamping rollers 74A and 74B). Therefore, without interfering with the upper guide 71 and the lower guide 72, the two pairs of clamping rollers 73A, 73B, 74A, and 74B can transport the sheet S1 while clamping it.

[0117] The upper guide 84 and the lower guide 85 are made of thin plates bent into a semi-circular shape, and when viewed from the side, the upper guide 84 and the lower guide 85 extend in a generally straight line. The upper guide 84 and the lower guide 85 are provided with clamping rollers 75A and 75B, clamping rollers 76A and 76B, clamping rollers 77A and 77B, clamping rollers 78A and 78B, and guide rollers 65 (upper drive roller 65A and lower driven roller 65B) for conveying the sheet S1 from the transfer roller 36 while the sheet S1 is clamped therein.

[0118] Here, clamping rollers 75B, 76B, 77B and 78B and upper drive roller 65A, which are located on the lower side, are driven to rotate clockwise by a motor (not shown). At the same time, clamping rollers 75A, 76A, 77A and 78A and lower driven roller 65B facing the clamping rollers 75B, 76B, 77B and 78B and upper drive roller 65A are driven to rotate.

[0119] Similar to the upper guide 71 and lower guide 72, through holes are formed in the upper guide 84 and lower guide 85 at positions corresponding to the paired clamping rollers 75A and 75B, clamping rollers 76A and 76B, clamping rollers 77A and 77B, clamping rollers 78A and 78B, and guide roller 65 (upper drive roller 65A and lower driven roller 65B). This allows the clamping rollers 75A and 75B, clamping rollers 76A and 76B, clamping rollers 77A and 77B, clamping rollers 78A and 78B, and guide roller 65 (upper drive roller 65A and lower driven roller 65B) to convey the sheet S1 while clamping it, without interfering with the upper guide 84 and lower guide 85.

[0120] The upper guide 84 and the lower guide 85 extend near the drive roller 80 of the belt 87. The upper guide 84 and the lower guide 85 are slightly inclined downward from the clamping rollers 78A and 78B toward the belt 87.

[0121] The belt 87 is wound around the drive rollers 80 and 81, which are provided along the extensions of the upper guide 84 and the lower guide 85, and the belt 87 is wound around the driven roller 82, which is provided near the drive roller 80, and the belt 87 receives the sheet S1 conveyed by the upper guide 84 and the lower guide 85 thereon.

[0122] On belt 87, a thin, plate-shaped guide cover 86 is provided, approximately parallel to belt 87 and with a slight gap, so as to face the placement surface on which the sheet S1 will be placed. This allows belt 87 to suppress vibration of the sheet S1 conveyed on belt 87 via drive rollers 80, 81 by means of the guide cover 86.

[0123] By contacting the first end of the sheet S1 conveyed by belt 87, the stop 67 is configured to stop the sheet S1 in the appropriate position. As a result, the sheet S1, conveyed by belt 87 and rotated via drive rollers 80 and 81, contacts the stop 67 and stands ready in the standby section 152 on belt 87. At this time, as drive rollers 80 and 81 continue to rotate, the sheet S1 slides on belt 87, and the first end (front edge) of the sheet S1 continues to press against the stop 67. As a result, registration adjustment of the sheet S1 in the top-bottom direction is performed.

[0124] It should be noted that, in the conveying direction of the sheet, the stop 67 is movably attached to the belt 87 according to the length of the sheet S1. That is, the longer the sheet S1, the closer the stop 67 is attached to the drive roller 81, and the shorter the sheet S1, the closer the stop 67 is attached to the drive roller 80. Therefore, the standby position of the sheet S1 can be adjusted by the attachment position of the stop 67.

[0125] At this time, the registration adjustment of the sheet S1 in the left and right directions is performed by the side pin device 67A set between the stop 67 and the upper drive roller 65A.

[0126] In belt 87, when stop 67 inhibits the feeding of sheet S1, guide roller 65 is positioned corresponding to the rear edge of sheet S1. Guide roller 65 has an upper drive roller 65A disposed above belt 64 and a lower driven roller 65B disposed below belt 64. When the feeding of sheet S1 described above is inhibited, the rear edge of sheet S1 is positioned between the upper drive roller 65A and the lower driven roller 65B.

[0127] In this embodiment, the upper guide 84 and the lower guide 85 extend to the vicinity of the drive roller 80. The upper guide 84 and the lower guide 85 are separate from the belt 87, but the gap between them is extremely small. Therefore, with the front edge of the first end of the sheet S1 in contact with the stop 67, the rear edge of the second end of the sheet S1 is positioned between the upper drive roller 65A and the lower driven roller 65B.

[0128] The lower driven roller 65B is configured such that, with the second end of the sheet S1 positioned between the upper drive roller 65A and the lower driven roller 65B of the guide roller 65, the lower driven roller 65B can move freely upward. This allows the lower driven roller 65B to rise above the placement surface of the belt 64 while the second end of the sheet S1 is held between the upper drive roller 65A and the lower driven roller 65B, causing the second end of the sheet S1 to separate upward from the placement surface of the belt 87.

[0129] In practice, synchronized with the re-grip of the second end of the sheet S1 by the second gripping device 40A of the return roller 40, the lower driven roller 65B of the guide roller 65 moves upward to lift the rear edge of the sheet S1, and the upper drive roller 65A is used to clamp the rear edge of the sheet S1. The upper drive roller 65A is configured to rotate to convey the sheet S1 toward the second gripping device 40A of the return roller 40. At this time, when the lower driven roller 65 clamps the sheet S1, the upper drive roller 65A can start rotating from a stopped state, or it can be configured to rotate continuously. It should be noted that at this time, the drive rollers 80 and 81 can continue to rotate or can stop rotating.

[0130] As a result, the belt 87 conveys the rear edge of the sheet S1, which is held between the upper drive roller 65A and the lower driven roller 65B, toward the return roller 40, and the rear edge of the sheet S1 is re-grabbed by the second gripping device 40A of the return roller 40.

[0131] The return roller 40 rotates clockwise in the direction of the arrow, while simultaneously holding the sheet S1 so that its rear edge is gripped by the second gripping device 40A, thereby conveying the sheet S1, which has been flipped from the front to the back, to the printing roller 33. By using the return roller 40, the flipped sheet S1, gripped by the second gripping device 40A, can be conveyed again from its rear edge to the printing roller 33, so that the surface on which the digital printing process has been performed on the printing roller 33 comes into contact with the peripheral surface of the printing roller 33.

[0132] A guide cover 40B is disposed on the return roller 40, located in the portion between the guide roller 65 and the printing roller 33. The guide cover 40B has an arcuate shape along the peripheral surface of the return roller 40 and is positioned slightly away from the peripheral surface. The guide cover 40B prevents the sheet S1 conveyed from the return roller 40 to the printing roller 33 from separating from the peripheral surface of the return roller 40 and vibrating.

[0133] In the digital printing unit 3, when the second gripping device 40A of the return roller 40 faces any one of the first gripping devices 33A to 33C of the printing roller 33, the sheet S1 is re-gripped from the return roller 40 to the printing roller 33, thereby conveying the flipped sheet S1 from the return roller 40 to the printing roller 33.

[0134] Therefore, the digital printing unit 3 re-feeds the sheet S1, which is re-grabbed by any one of the first gripping devices 33A to 33C of the printing roller 33, to the inkjet nozzle unit 34, while absorbing its entire surface onto the peripheral surface, performing digital printing on the back side of the sheet S1, and then conveying it to the conveyor belt DB via the transfer roller 36, thereby completing the double-sided printing process.

[0135] It should be noted that the areas of the upper guide 84 and the lower guide 85 are defined as the conveying section 151 for conveying the sheet S1, and the area of ​​the belt 87 is defined as the standby section 152 for temporarily holding the sheet S1 in a standby state to transfer the sheet S1 from the return roller 40 to the printing roller 33. These are limitations for convenience and are not necessarily limited to them. In this embodiment, the "flipping device" consists of the guide roller 65 and the return roller 40.

[0136] Next, in this embodiment, a description will be given of how the transport destination of the sheet S1 is sorted between the following two cases: first, the sheet S1 from the conveyor roller 36 is transported to the sheet conveying unit 4 via the upper guide 71 and the lower guide 72; second, the sheet S1 from the conveyor roller 36 is transported to the conveying section 151 via the upper guide 84 and the lower guide 85.

[0137] like Figure 11 As shown, when the sheet S1 held by the gripping device 36A of the conveying roller 36 is conveyed to the conveying section 151 via the upper guide 84 and the lower guide 85, the gripping device 36A releases the sheet S1 ahead of time. Finally, the gripping device 36A releases the sheet S1 before the leading edge of the sheet S1 gripped by the gripping device 36A passes the branch point between the guides 71, 72 and the guides 84, 85. As a result, under the weight of the sheet S1, the leading edge is naturally guided to the upper guide 84 and the lower guide 85, and the sheet S1 is conveyed to the conveying section 151.

[0138] Simultaneously, when the sheet S1, held by the gripping device 36A of the conveying roller 36, is conveyed to the sheet conveying unit 4 via the upper guide 71 and the lower guide 72, the moment when the gripping device 36A releases the sheet S1 is delayed as much as possible. Preferably, the gripping device 36A releases the sheet S1 after the leading edge of the sheet S1 gripped by the gripping device 36A has passed the branch point between the guides 71, 72 and the guides 84, 85. As a result, the leading edge of the sheet S1 does not droop towards the upper guide 84 and the lower guide 85 under its own weight, but is guided to the upper guide 71 and the lower guide 72, and the sheet S1 is conveyed to the sheet conveying unit 4.

[0139] As described above, the digital printing press 100 of this embodiment includes: a transfer roller 36, which serves as a second roller, faces the printing roller 33, and includes a third gripping device 36A configured to receive processed sheet S1 from the printing roller 33; the transfer roller 36 is configured to convey the sheet S1 gripped by the gripping device 36A; a first guide extending from the transfer roller 36 to the sheet conveying unit 4; and a second guide branching from the first guide and extending to a belt 87 in the standby section 152. The belt 87 is configured to receive the sheet S1 conveyed by the second guide.

[0140] The first guide includes an upper guide 71 and a lower guide 72, which comprise two plate-like members facing each other. The first guide includes a first roller configured to convey sheet S1 from conveying roller 36 to sheet conveying unit 4. The first roller includes two pairs of clamping rollers: clamping rollers 73A and 73B, and clamping rollers 74A and 74B.

[0141] The second guide includes an upper guide 84 and a lower guide 85, each comprising two plate-like members facing each other. The second guide includes a semi-circular portion. The second guide includes a second roller configured to convey sheet S1 from conveyor roller 36 to belt 87. The second roller includes four pairs of clamping rollers (clamping rollers 75A and 75B, clamping rollers 76A and 76B, clamping rollers 77A and 77B, clamping rollers 78A and 78B) and one pair of guide rollers (guide rollers 65A and 65B).

[0142] One example of a sorting mechanism is a conveyor roller 36. Another example of a sorting mechanism is a plate 101 disposed at a branch point between a first guide and a second guide, and configured to selectively block either the first guide or the second guide.

[0143] Next, the operation of digital printing unit 3 will be described. When the double-sided printing mode is selected, as follows: Figure 12 As shown, the leading edge of the sheet S1 gripped by the gripping device 32A of the feed roller 32 is re-gripped by the first gripping device 33A of the printing roller 33, for example.

[0144] like Figure 13 As shown, the printing roller 33 rotates to re-grip the sheet S1 held by the first gripping device 33A to the third gripping device 36A of the transfer roller 36.

[0145] Then, as Figure 14 As shown, the third gripping device 36A of the conveyor roller 36 releases the sheet S1 at a predetermined time. As a result, as... Figure 15 As shown, sheet S1 is conveyed by clamping rollers 75A, 75B, 76A, 76B, 77A, 77B, 78A, and 78B, and is conveyed by guide rollers 65 in conveying section 151 via upper guide member 84 and lower guide member 85.

[0146] like Figure 16 As shown, sheet S1 is conveyed from conveying section 151 to standby section 152 via clamping rollers 77A, 77B, 78A, 78B and guide roller 65.

[0147] like Figure 17As shown, in the standby section 152, the sheet S1 placed on the belt 87 is conveyed by the belt 87, the front edge of the sheet S1 contacts the stop member 67, and the registration adjustment is performed by activating the side pin device 67A.

[0148] like Figure 18 As shown, synchronized with the arrival of the second gripping device 40A of the return roller 40 for re-gripping, the lower driven roller 65B rises to lift the rear edge of the sheet S1, which is locked by the stop 67 of the standby section 152, above the belt 87, and clamps it using the upper drive roller 65A. The upper drive roller 65A of the guide roller 65 rotates to convey the sheet S1 toward the second gripping device 40A of the return roller 40. The rear edge of the sheet S1 is gripped from the guide roller 65 by the second gripping device 40A of the return roller 40, and then the sheet S1 is re-gripped from the second gripping device 40A of the return roller 40 to the first gripping device 33C of the printing roller 33.

[0149] In this configuration, the printing cylinder 33 conveys the flipped sheet S1 to the back side after the sheet S1 has been transferred from the return cylinder 40 to the printing cylinder 33. Therefore, digital printing can be performed on the back side of the sheet S1, which is the sheet S1 that was re-transferred by the printing cylinder 33 that performed printing on the front side, via the inkjet nozzle unit 34.

[0150] As described above, in the digital printing unit 3 of the digital printing equipment 1, the front side of the sheet S1 conveyed by the printing roller 33 is digitally printed by the inkjet nozzle unit 34, and then the sheet S1 is conveyed to the conveying unit 151 via the transfer roller 36. The end (front edge) of the sheet S1 contacts the stop member 67 of the standby unit 152, and registration adjustment is performed by activating the transverse pin device 67A, that is, the position adjustment of the standby position of the sheet S1.

[0151] Then, in sync with the second gripping device 40A of the return roller 40 approaching the rear edge of the sheet S1, the lower driven roller 65B rises to lift the rear edge of the sheet S1 above the belt 64 and clamp it using the upper drive roller 65A, and the upper drive roller 65A of the guide roller 65 rotates to convey the sheet S1 toward the second gripping device 40A of the return roller 40.

[0152] As a result, the digital printing unit 3 can reliably enable the second gripping device 40A of the return roller 40 to grip the rear edge of the sheet S1, and to re-grip the sheet S1 from the second gripping device 40A of the return roller 40 to the first gripping devices 33A to 33C of the printing roller 33. Therefore, the sheet S1 can be fed back to the printing roller 33 while maintaining the registration adjustment state of the sheet S1 that has already been performed.

[0153] Therefore, with registration adjustment performed via the printing cylinder 33 and the inkjet nozzle section 34, the digital printing unit can perform digital printing processing on the back side of the sheet S1. This prevents misalignment between the printing results on the front and back sides, and improves the printing quality on both sides of the sheet S1.

[0154] Furthermore, the digital printing unit can also reuse the printing cylinder 33 and inkjet nozzle 34, which perform digital printing processing on the front side of the sheet S1, to perform digital printing processing on the back side of the sheet S1. Therefore, since the printing cylinder 33 and inkjet nozzle 34 can be shared for digital printing processing on both the front and back sides, double-sided printing of the sheet S1 can be performed with high precision without increasing the overall size of the equipment.

[0155] It should be noted that in the digital printing unit, the upper guide 84 and lower guide 85 of the transport section 151 are attached in a state that is slightly inclined downward from the clamping rollers 78A and 78B toward the belt 87, and the belt 87 is also attached obliquely to the surface on which the sheet is placed in the same manner. This means that even if the sheet S1 placed on the belt 87 slides and is no longer transported by the rotation of the belt 87, the sheet S1 is naturally transported toward the stop 67 under its own weight, and the situation where the registration of the sheet S1 in the top-bottom direction is not adjusted can be avoided.

[0156] [Other Embodiments]

[0157] It should be noted that in the first and second embodiments described above, a printing roller 33 of three times the size of a roller is used as the first roller. However, the present invention is not limited to this, and a printing roller of two times the size, four times the size, six times the size, etc., can be used as the printing roller.

[0158] In the first embodiment, the conveying unit 51 integrated with the standby unit 52 is used as a conveying unit. However, the present invention is not limited to this, and a conveying unit separate from the standby unit 52 may also be used.

[0159] In the first and second embodiments, the conveyor roller 36, which is a single-size roller, is used as the second roller. However, the present invention is not limited to this, and conveyor rollers of double-size rollers, triple-size rollers, etc., may also be used.

[0160] In the first and second embodiments, the return roller 40, which is a single-size roller, is used as a flipping device. However, the present invention is not limited to this, and a flipping swinging device having the same configuration as the swinging device 31 and swinging from the standby section 52, 152 toward the printing roller 33 can be used.

[0161] In the first and second embodiments, the movably attached stop 67 serves as a first adjustment device. However, the invention is not limited thereto; if the size of the sheet S1 is fixed, the stop 67 fixed at a predetermined position can be used.

[0162] Furthermore, in the first and second embodiments, the movably attached stop 67 serves as a first adjustment device. However, the invention is not limited to this; the following configuration can also be used to stop the feeding of the sheet S1 and adjust the standby position.

[0163] Instead of using belts 64 and 87 and stop 67, in the first and second embodiments, at the position of guide roller 65, a [feature] is provided as follows: Figure 19 The pair of clamping rollers 79A and 79B shown are used for clamping and conveying sheet S1. The clamping rollers 79A and 79B have a rotating shaft extending in a direction perpendicular to the conveying direction of sheet S1, and are capable of rotating and moving in the axial direction.

[0164] In this case, such as Figure 20 As shown, the digital printing equipment 1 (sheet processing equipment) includes a sheet size detection sensor 91, a sheet side edge position detection sensor 92, an encoder 93, a clamping roller rotation motor 94, a clamping roller axis adjustment mechanism 95, and a controller 96. The sheet size detection sensor 91 is used to detect the length of the sheet S1 in the conveying direction (top-to-bottom direction), and is composed of a photoelectric sensor or the like. The sheet side edge position detection sensor 92 is used to detect the position of one side edge of the sheet S1, and is also composed of a photoelectric sensor or the like. The encoder 93 can detect the phase of the drive unit of the digital printing equipment 1. The motor 94 rotates the clamping rollers 79A and 79B. It should be noted that only the clamping roller 79A, which is located above the belts 64 and 87, can be driven to rotate by the motor 94, and the clamping roller 79B, which is located below the belts 64 and 87, can be configured to be driven to rotate. The adjusting mechanism 95 adjusts the axial position of the clamping rollers 79A and 79B. The controller 96 controls the motor 94 and the adjusting mechanism 95 based on the outputs of the sheet size detection sensor 91, the sheet side edge position detection sensor 92, and the encoder 93.

[0165] The position adjustment of the sheet S1 using these configurations in the standby sections 52 and 152 will be described. The sheet S1, fed to the clamping rollers 79A and 79B, is conveyed to the standby sections 52 and 152 by the rotation of the clamping rollers 79A and 79B. At this time, the controller 96 causes the motor 94 to rotate until the length information of the sheet S1 from the sheet size detection sensor 91 reaches a suitable conveying amount for the sheet S1 in the standby sections 52 and 152, and then stops the conveying to adjust the registration position in the top-to-bottom direction.

[0166] Subsequently, based on the position information of sheet S1 in the width direction from sheet side edge position detection sensor 92, controller 96 causes adjustment mechanism 95 to operate until sheet S1 reaches the correct registration position in the width direction.

[0167] Subsequently, based on the signal from the encoder 93, at the moment when the second end of the sheet S1 (the second end of the sheet S1 has been aligned in the top-bottom direction and the left-right direction) is gripped by the second gripping device 40A of the return roller 40, the controller 96 causes the motor 94 to reverse. As a result, the clamping rollers 79A and 79B rotate in opposite directions, and the second end of the sheet S1 is gripped by the second gripping device 40A.

[0168] In this embodiment, the first adjustment device includes: clamping rollers 79A and 79B, which serve as a pair of rollers and are configured to clamp the sheet on two surfaces of the sheet S1, and have a rotation axis extending in a direction perpendicular to the conveying direction of the sheet S1; a motor 94, which is configured to rotate at least one of the clamping rollers 79A and 79B; and a controller 96, which is configured to control the motor 94 according to the size of the sheet S1. The first adjustment device may further include a sheet size detection sensor 91, which serves as a first sensor and is configured to detect the length of the sheet S1 in the conveying direction and output the result to the controller 96.

[0169] The second adjustment device includes: clamping rollers 79A and 79B, which serve as a pair of rollers configured to clamp a sheet on two surfaces of the sheet S1 and have a rotation axis extending in a direction perpendicular to the conveying direction of the sheet S1; an adjustment mechanism 95 configured to adjust the axial position of at least one of the clamping rollers 79A and 79B; and a controller 96 configured to control the adjustment mechanism 95 based on the position of the side edge of the sheet S1. The second adjustment device may further include a sheet side edge position detection sensor 92, which serves as a second sensor configured to detect the position of the side edge of the sheet S1.

[0170] Furthermore, in the second embodiment, by adjusting the timing of the release of the sheet S1 by the gripping device 36A of the conveyor roller 36, the following switching is performed: conveying the sheet S1 from the conveyor roller 36 to the sheet conveying unit 4 via the upper guide 71 and the lower guide 72, and conveying the sheet S1 to the belt conveyor section 150 via the upper guide 84 and the lower guide 85. However, the present invention is not limited thereto, and as... Figure 21A and Figure 21B As shown, the plate-shaped switching unit 101, used as a sorting mechanism, can be located at the branch point between the upper guide 71 and the lower guide 72 and the upper guide 84 and the lower guide 85. The switching unit 101 can be switched to either the upper guide 71 and the lower guide 72 side or the upper guide 84 and the lower guide 85 side. Furthermore, the control of the release timing of the sheet S1 by the gripping device 36A and the switching of the plate-shaped switching unit 101 can be combined to improve reliability.

[0171] Furthermore, in the first and second embodiments, the application of the sheet processing equipment to digital printing equipment has been described. However, the present invention is not limited thereto, and can be applied to bias printing equipment, inspection equipment, foil conveying equipment, stamping equipment, etc. Depending on the application of the sheet processing equipment, a blanket roller for bias printing, a printing roller for foil conveying or stamping, etc., can be used instead of an inkjet nozzle unit as a processing device for processing the sheet surface.

[0172] Furthermore, in the first and second embodiments, sheet conveying in the conveying section 51 and the standby sections 52, 152 is performed by means of a belt, and the sheet S1 is prevented from shaking and floating from the belt by a guide cover provided along the belt. However, the present invention is not limited to this, and suction holes can be formed in the belt to provide a configuration for generating negative pressure on the surface of the belt that does not contact the sheet. Instead of a guide cover, shaking and floating from the belt can be prevented while conveying the sheet S1 by suction.

[0173] [List of Labels in the Attached Image]

[0174] 1, 100…Digital printing equipment, 2…Sheet feeder, 3…Digital printing unit, 4…Sheet conveying unit, 21…Stacking plate, 22, 42…Stacked sheets, 23…Sheet picker, 31…Oscillating device, 32…Feeding roller, 33…Printing roller, 36…Transfer roller, 39…Pre-flipping roller, 40…Return roller, FB…Feeder plate, DB…Conveyor belt, S1…Sheet, 51, 151…Conveying section, 52, 152…Standby section, 65…Guide roller, 67…Stop, 62, 68, 80, 81…Drive roller, 63, 82…Driven roller, 64, 87…Belt, 61…Guide cover, 71, 84…Upper guide, 72, 85…Lower guide, 73 to 78…Clamping roller.

Claims

1. A sheet processing device, comprising: A first roller, the first roller including a first gripping device configured to grip an end of a sheet in a top-to-bottom direction, and configured to convey the sheet when the end is gripped by the first gripping device; A processing device is disposed outside the first roller so as to face the peripheral surface of the first roller, and the processing device is configured to perform processing on the surface of the sheet conveyed by the first roller; A discharge device configured to discharge the treated sheet; A standby section is configured to receive the processed sheet from a first end of the sheet and hold it in a standby state, the first end being the end gripped by the first gripping device. A sorting mechanism configured to selectively sort the sheet from the first roller to the discharge device or the standby section; as well as A flipping device includes a second gripping device configured to grip a second end of the sheet waiting in the standby section, the second end being the end of the sheet that has not been gripped by the first gripping device in the top-to-bottom direction, and the second gripping device is configured to convey the second end of the sheet to the first gripping device of the first roller, such that the surface on which the processing device performs the processing comes into contact with the peripheral surface of the first roller.

2. The sheet processing apparatus according to claim 1 further includes a first adjusting device, the first adjusting device being configured to adjust the position of the second end of the sheet in the standby section.

3. The sheet processing equipment according to claim 2, wherein, The standby section includes a belt configured to transport the sheet, and The first adjusting device includes a stop, the stop being configured such that the first end of the sheet on the belt contacts the stop.

4. The sheet processing equipment according to claim 2, wherein, The first adjusting device includes: A pair of rollers configured to clamp two surfaces of the sheet and having a rotation axis extending in a direction perpendicular to the conveying direction of the sheet; A motor, configured to rotate at least one of the pair of rollers; and A controller configured to control the motor based on the size of the sheet.

5. The sheet processing apparatus according to claim 2 further includes a second adjusting device, the second adjusting device being configured to adjust the position of the side edge portion of the sheet in the width direction before it is gripped by the second gripping device in the standby section.

6. The sheet processing equipment according to claim 5, wherein, The second adjusting device includes: A pair of rollers configured to move toward and away from each other, and the pair of rollers having a rotation axis extending in a direction parallel to the conveying direction of the sheet; A motor, configured to rotate the pair of rollers when the pair of rollers clamp the two surfaces of the sheet; and A side guide is provided, which is configured such that the side edge of the sheet, which moves in a direction perpendicular to the conveying direction by the rotation of the pair of rollers, contacts the side guide.

7. The sheet processing equipment according to claim 5, wherein, The second adjusting device includes: A pair of rollers configured to clamp two surfaces of the sheet and having a rotation axis extending in a direction perpendicular to the conveying direction of the sheet; An adjusting mechanism configured to adjust the axial position of the pair of rollers; and A controller configured to control the adjustment mechanism based on the position of the side edge of the sheet.

8. The sheet processing equipment according to claim 3, further comprising: A second roller, facing the first roller and including a third gripping device configured to receive processed sheet material from the first roller, and the second roller configured to convey sheet material gripped by the third gripping device; as well as A pre-rotating roller, facing the second roller, includes a fourth gripping device configured to receive the sheet from the second roller, the pre-rotating roller being configured to convey the sheet gripped by the fourth gripping device, wherein... The sorting mechanism is composed of the second roller, and The belt is configured to receive the sheet conveyed by the pre-rotating roller.

9. The sheet processing apparatus according to any one of claims 1 to 8, wherein, The flipping device includes a guide member configured to lift the second end of the sheet waiting in the standby section and to convey the sheet to the second gripping device.

10. The sheet processing equipment according to claim 1, wherein, The standby unit includes a belt configured to transport the sheet; and The flipping device includes: Upper roller, the upper roller being disposed above the belt; and A lower roller, disposed below the belt, is movable in a vertical direction and configured to lift the sheet together with the belt, and to clamp the sheet together with the upper roller, wherein... The upper roller and the lower roller are configured to rotate in the direction in which the sheet moves toward the second gripping device.

11. The sheet processing equipment according to claim 3, further comprising: A second roller, facing the first roller and including a third gripping device configured to receive processed sheet material from the first roller, and the second roller configured to convey sheet material gripped by the third gripping device; A first guide extends from the second roller to the discharge device; as well as A second guide, which branches off from the first guide and extends into the strip, wherein... The belt is configured to receive the sheet conveyed by the second guide.

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