JP6133108B2 - Sheet feeding device - Google Patents

Description

  The present invention relates to a sheet supply apparatus used in a digital printing apparatus that performs printing on a sheet by an inkjet method.

  Conventionally, as a digital printing apparatus that prints on a sheet by an ink jet method, a sheet-like recording medium is accurately mounted on a surface of a table moving in one direction by a nail, and ink is applied from four color ink jet nozzles to the recording medium. In some cases, image recording is performed by ejecting the liquid (for example, see Patent Document 1).

JP 2009-262537 A

  However, in Patent Document 1, a recording medium is conveyed in a horizontal direction through a table, and image recording is performed by the heads of inkjet nozzles arranged in series along the table. Because of this configuration, in order to perform double-sided printing on a recording medium, the recording medium that has been printed on the front side is mounted on the table again with the back side upside down, and image recording is performed on the back side by the heads of the inkjet nozzles. There is a problem that printing on the front and back surfaces cannot be performed efficiently.

  The present invention has been made to solve such a problem, and an object of the present invention is to propose a sheet feeding apparatus capable of efficiently performing printing on the front surface and the back surface.

In order to solve such a problem, in the invention of claim 1, a printing cylinder that holds and conveys a sheet, a processing unit that performs a digital printing process on the sheet conveyed by the printing cylinder, and a digital that is processed by the processing unit. A sheet reversing unit that reverses the front and back sides of the printed sheet and delivers the sheet to the printing cylinder; and a sheet feeding unit that feeds the sheet to the printing cylinder. The sheet feeding unit includes a negative pressure source and the negative pressure source. A soccer device that is connected to a pressure source and supplies a sheet to the printing cylinder, and when the sheet is intermittently supplied, the soccer device is negatively charged with respect to the soccer device in a second period longer than a first period in which the sheet is continuously supplied to the printing cylinder. and switching means for switching the action of pressure, the the switching means provided between the sucker device, said negative pressure source and the negative for continuous supply and disconnecting in said first period the connection between the sucker device A rotary valve, wherein the soccer device operates in the first cycle, the second cycle is twice as long as the first cycle, and the switching means includes the negative pressure source and the football Between the negative pressure source and the intermittent supply rotary valve, which is provided between the negative pressure source and the intermittent supply rotary valve. A first connection state that connects the negative pressure source and the soccer device without going through the intermittent supply rotary valve, and connects the negative pressure source and the soccer device through the intermittent supply rotary valve. A three-way valve that switches to the second connection state to be connected, and when the sheet is continuously supplied, the negative connection from the negative pressure source through the negative pressure rotary valve for continuous supply is made in the first connection state. Pressure When the sheet is intermittently supplied by acting on the soccer device, the negative pressure from the negative pressure source is applied in the second connection state and through the intermittent supply rotary valve and the continuous supply negative pressure rotary valve. The three-way valve is switched to act on the soccer device .

According to a second aspect of the present invention, there is provided a printing cylinder that holds and conveys a sheet, a processing unit that performs a digital printing process on a sheet conveyed by the printing cylinder, and a sheet that is digitally printed by the processing unit. A sheet reversing unit that reverses the front and back and delivers the sheet to the printing cylinder, and a sheet feeding unit that feeds the sheet to the printing cylinder, the sheet feeding unit being connected to the negative pressure source and the negative pressure source. For switching the negative pressure on the soccer device in a second period longer than the first period in which sheets are continuously supplied to the printing cylinder when the sheet is intermittently supplied to the printing cylinder. And a negative pressure rotary valve for continuous supply, which is provided between the switching means and the soccer device, and connects and disconnects the negative pressure source and the soccer device at the first period. The soccer device operates in the first cycle, the second cycle is twice as long as the first cycle, and the switching means is provided between the negative pressure source and the soccer device. Provided between the negative pressure source and the intermittent supply rotary valve, and provided between the negative pressure source and the intermittent supply rotary valve for connecting and disconnecting the negative pressure source and the soccer device in the second cycle. A first connection state in which a pressure source and the soccer device are connected without going through the intermittent supply rotary valve, and a second connection state in which the negative pressure source and the soccer device are connected through the intermittent supply rotary valve A three-way valve that switches to a connected state, and in the case of continuously supplying seats, the soccer device applies the negative pressure from the negative pressure source through the negative pressure rotary valve for continuous supply in the first connected state. Acted on When the sheet is intermittently supplied, negative pressure from the negative pressure source is applied to the soccer device through the second connection state and through the intermittent supply rotary valve and the continuous supply negative pressure rotary valve. The three-way valve is switched so that the seat supply unit includes a positive pressure source for applying a positive pressure to the soccer device .

  In the invention of claim 3, the switching means is provided between the negative pressure source and the soccer device, and for intermittent supply for connecting and disconnecting the negative pressure source and the soccer device in the second period. A first connection state that is provided between the rotary valve, the negative pressure source, and the intermittent supply rotary valve, and connects the negative pressure source and the soccer device without going through the intermittent supply rotary valve; A three-way valve for switching to the second connection state in which the negative pressure source and the soccer device are connected via the intermittent supply rotary valve, provided between the switching means and the soccer device, A negative supply rotary valve for continuous supply that connects and disconnects the negative pressure source and the soccer device in the first cycle, and when the sheet is continuously supplied, the continuous supply is performed in the first connection state. When a negative pressure from the negative pressure source is applied to the soccer device via a negative pressure rotary valve to supply the seat intermittently, the second connection state is set, and the intermittent supply rotary valve and the continuous supply are used. The three-way valve is switched so that negative pressure from the negative pressure source is applied to the soccer device via a negative pressure rotary valve.

  According to a fourth aspect of the present invention, the sheet supply unit includes a positive pressure source that applies a positive pressure to the soccer device.

  According to the first aspect of the present invention, the sheet supply unit sucks the sheet by the soccer device by the negative pressure from the negative pressure source that applies the negative pressure for sucking the sheet and conveys the sheet to the printing cylinder. Then, the processing unit performs digital printing on the surface of the sheet, and the sheet whose surface has been digitally printed is reversed by the sheet reversing unit and then delivered to the printing cylinder, while the sheet supply unit intermittently supplies the sheet. In this case, since it is only necessary to switch the action of the negative pressure on the soccer device from the first period to the second period, it is possible to efficiently supply the sheet and to efficiently print the front and back surfaces.

It is a side view which shows the whole structure of a digital printing apparatus. It is a side view which shows the structure of an inversion swing apparatus. It is a basic diagram which shows the structure of a paper feeder. It is a block diagram which shows the structure of the control system of a digital printing apparatus. 6 is a timing chart for explaining continuous sheet feeding in a digital printing apparatus. It is a side view which shows the printing process (1) in a digital printing apparatus. It is a side view which shows the printing process (2) in a digital printing apparatus. 6 is a timing chart for explaining intermittent paper feeding in the digital printing apparatus. It is a side view which shows the printing process (3) in a digital printing apparatus. It is a side view which shows the printing process (4) in a digital printing apparatus. It is a side view which shows the printing process (5) in a digital printing apparatus.

<Configuration of digital printing device>
As shown in FIG. 1, a digital printing apparatus 1 as a sheet supply apparatus includes a paper feeding device 2 as a sheet supply unit, a digital printing unit 3 as a processing unit, and a paper discharge device 4 as a discharge unit.

  The sheet feeding device 2 includes a stacking base 21 on which a plurality of sheets S1 are stacked, a soccer device 23 that conveys the uppermost sheet S1 of the stacking base 21 to the feeder board FB, and an intermittent connection connected to the soccer device 23. A paper feed rotary valve 27 is provided. The soccer device 23 includes a first suction 23a and a second suction 23b.

  On the front end side in the sheet conveying direction of the feeder board FB, it is supported by the frame 3a of the digital printing unit 3 so as to be swingable, and holds the front end (the end on the holding side) as one end of the sheet S1. A swing device 31f provided with a gripper device is provided. A paper feed side transfer drum 32 is disposed opposite to the swing device 31f, and the paper feed side transfer drum 32 is rotatably supported by the frame 3a.

  The feeding side transfer cylinder 32 is provided with a gripping claw device 32a that holds the leading end of the sheet S1 delivered by the gripping claw device of the swing device 31f. In the digital printing unit 3, the swing device 31f and the sheet feeding side transfer cylinder 32 constitute an upstream sheet conveying device.

  A printing cylinder 33 is disposed in contact with the sheet feeding side transfer cylinder 32 on the downstream side in the sheet conveying direction from the swing device 31f, and the printing cylinder 33 is rotatably supported by the frame 3a. The printing cylinder 33 includes a printing cylinder holding claw device 33a, 33b, 33c that receives and holds the leading end of the sheet S1 from the holding claw device 32a of the paper feeding side transfer cylinder 32, and the printing cylinder holding claw device 33a, 33b, 33c. Correspondingly provided support surfaces 33d, 33e, 33f for supporting the sheet S1, and in the present embodiment, a triple cylinder is provided in which three sets of the printing cylinder holding nail device and the support surface are provided. The diameter of the paper feeding side transfer cylinder 32 is three times as large. Here, the printing cylinder holding claw devices 33a, 33b, and 33c that hold the sheet S1 are provided in a state in which the phases are shifted from each other by 120 degrees in the circumferential direction.

  A plurality of suction holes are formed in the support surfaces 33d, 33e, and 33f of the printing cylinder 33, and the plurality of suction holes are connected to a negative pressure source. An inkjet nozzle portion 34 as a processing unit is disposed opposite to the peripheral surface of the printing cylinder 33 on the downstream side in the sheet conveyance direction from the portion where the printing cylinder 33 is in contact with the sheet feeding side transfer cylinder 32. .

  A plurality of inkjet nozzle heads 34 a to 34 d in which inks of different colors are set are arranged in the inkjet nozzle portion 34 side by side along the circumferential surface of the printing cylinder 33, and each of them is a circumferential surface of the printing cylinder 33. Is oriented. The inkjet nozzle heads 34a to 34d are arranged close to the printing cylinder 33 so that the gap between the printing nozzle 33 and the sheet S1 adsorbed on the entire surface of the supporting surface 33d, 33e, 33f is slightly spaced. The printing cylinder 33 and the inkjet nozzle unit 34 constitute a sheet printing apparatus.

  An ink printed on the sheet S1 by irradiating the sheet S1 with light such as infrared rays or ultraviolet rays is disposed on the downstream side of the printing cylinder 33 in the sheet conveyance direction with respect to the inkjet nozzle portion 34, and is irradiated with light such as infrared rays or ultraviolet rays. An ink drying lamp 35 is provided as a drying device for drying. Here, the term “drying” includes evaporation of moisture of the ink by applying thermal energy and curing of the ink, which can be called solidification.

  A first paper discharge side transfer cylinder 36 is disposed in contact with the printing cylinder 33 on the downstream side in the sheet conveying direction from the ink jet nozzle portion 34, and the first paper discharge side transfer cylinder 36 is rotatable to the frame 3a. It is supported by. The first paper discharge side transfer cylinder 36 is provided with a gripping claw device 36a that receives and holds the leading end of the sheet S1 conveyed by the printing cylinder 33 from the printing cylinder gripping claw devices 33a, 33b, and 33c.

  A second paper discharge side transfer cylinder 37 is in contact with the first paper discharge side transfer cylinder 36 on the downstream side of the first paper discharge side transfer cylinder 36 in contact with the printing cylinder 33 in the sheet conveying direction. The second paper discharge side transfer cylinder 37 is rotatably supported by the frame 3a. The second paper discharge side transfer drum 37 is provided with a gripping claw device 37a for receiving and holding the leading edge of the sheet S1 conveyed by the first paper discharge side transfer drum 36.

  A paper take-up cylinder 38 is disposed in contact with the first paper discharge-side transfer cylinder 37 on the downstream side of the second paper discharge-side transfer cylinder 37 with respect to the first paper discharge-side transfer cylinder 36. 3a is rotatably supported. The paper take-up cylinder 38 is provided with a gripping claw device 38a that receives and holds the leading end of the sheet S1 conveyed by the second paper discharge side transfer cylinder 37.

  Below the paper drum 38, a belt-conveyor-like delivery belt 40 that conveys the sheet S1 is disposed. On the leading end side of the delivery belt 40 in the sheet conveyance direction, a stacking base 41 on which the sheet S1 subjected to digital printing processing by the digital printing unit 3 is stacked is provided. The paper take-up cylinder 38, the delivery belt 40, and the stacking base 41 constitute the paper discharge device 4, and the path of the sheet S1 conveyed by the paper take-up cylinder 38 and the delivery belt 40 constitutes the sheet discharge path.

  A pre-reverse double cylinder 39 is disposed in contact with the paper discharge cylinder 38 on the downstream side of the second paper discharge side transfer cylinder 37 and the paper take-up cylinder 38. The pre-reverse double cylinder 39 is disposed on the frame 3a. It is supported rotatably. The pre-inversion double cylinder 39 is a double cylinder having a diameter twice that of the second paper discharge side transfer cylinder 37, and receives and holds the leading end of the sheet S1 conveyed by the second paper discharge side transfer cylinder 37. A holding claw device 39a is provided.

  As shown in FIG. 2, as shown in FIG. 2, the rear end (the other end portion of the sheet S <b> 1) is located downstream of the contact portion of the pre-reverse double cylinder 39 with the second discharge-side transfer cylinder 37. A reversing swing device 31b provided with a gripper device 31bt for receiving and holding the (butt side end) is disposed oppositely. In addition, a sheet reversing unit configured to reverse the front and back of the sheet S1 by the pre-reversing double cylinder 39 and the reversing swing device 31b and deliver it to the printing cylinder 33 is configured.

  As shown in FIG. 3, the paper feeding device 2 includes a soccer device 23, an intermittent paper feeding rotary valve 27 as an intermittent feeding rotary valve, a negative pressure source 25a, and a positive pressure source 25b, and a negative pressure source 25a. Between the positive pressure source 25b and the intermittent feed rotary valve 27, and further for intermittent feed. Between the rotary valve 27 and the soccer device 23, a negative pressure rotary valve 26a for continuous feeding as a negative pressure rotary valve for continuous supply and a positive pressure rotary valve 26b for continuous feeding as a positive pressure rotary valve for continuous supply are arranged. It is installed. The intermittent feed rotary valve 27, the continuous feed negative pressure rotary valve 26a, and the continuous feed positive pressure rotary valve 26b are each driven to open and close by a dedicated motor.

  The negative pressure source 25a and the three-way valve 24a are connected via a negative pressure pipe 28a. The three-way valve 24a and the continuous feeding negative pressure rotary valve 26a are connected via a negative pressure pipe 28b and a negative pressure pipe 28d. The three-way valve 24a and the intermittent feeding rotary valve 27 are connected via a negative pressure pipe 28c. It is connected. The intermittent feeding rotary valve 27 and the continuous feeding negative pressure rotary valve 26a are connected via a negative pressure pipe 28d, and the continuous feeding negative pressure rotary valve 26a and the soccer device 23 are connected via a negative pressure pipe 28e. Has been. Note that one end of the negative pressure pipe 28b is coupled to the negative pressure pipe 28d, and a negative pressure flow path is formed between the three-way valve 24a and the continuous feeding negative pressure rotary valve 26a. The three-way valve 24a and the intermittent feed rotary valve 27 constitute negative pressure switching means as switching means for switching on / off the action of negative pressure on the soccer device 23 from the negative pressure source 25a.

  The three-way valve 24a closes the negative pressure pipe 28c side and opens the negative pressure pipe 28b side to connect the negative pressure source 25a and the soccer device 23 without the intermittent feed rotary valve 27 (first feed). Connection state), and the negative pressure pipe 28c side is opened and the negative pressure pipe 28b side is closed and the negative pressure source 25a and the soccer device 23 are connected via the intermittent feed rotary valve 27 (second connection). Connection state).

  The positive pressure source 25b and the three-way valve 24b are connected via a positive pressure pipe 29a. The three-way valve 24b and the continuous feed positive pressure rotary valve 26b are connected via a positive pressure pipe 29b and a positive pressure pipe 29d, and the three-way valve 24b and the intermittent feed rotary valve 27 are connected via a positive pressure pipe 29c. It is connected. The intermittent feeding rotary valve 27 and the continuous feeding positive pressure rotary valve 26b are connected via a positive pressure pipe 29d, and the continuous feeding positive pressure rotary valve 26b and the soccer device 23 are connected via a positive pressure pipe 29e. Has been. One end of the positive pressure pipe 29b is coupled to the positive pressure pipe 29d, and a positive pressure flow path is formed between the three-way valve 24b and the continuous feed positive pressure rotary valve 26b. The three-way valve 24b and the intermittent paper feeding rotary valve 27 constitute positive pressure switching means as switching means for switching on / off the action of positive pressure on the soccer device 23 from the positive pressure source 25b.

  The three-way valve 24b closes the positive pressure pipe 29c side and opens the positive pressure pipe 29b side to connect the positive pressure source 25b and the soccer device 23 without the intermittent feed rotary valve 27 (first feed). ), And the positive pressure tube 29c side is opened and the positive pressure tube 29b side is closed and the positive pressure source 25b and the soccer device 23 are connected via the intermittent feed rotary valve 27 (second connection). Connection state).

<Control system configuration>
Next, the configuration of the control system of the digital printing apparatus 1 will be described. As shown in FIG. 4, a control device 100 constituted by a CPU (Central Processing Unit) includes a print mode selection switch 101 that selects a single-sided printing mode or a double-sided printing mode, and a rotary encoder 103 as a phase detector. In addition to the connection, the intermittent feed rotary valve 27, the three-way valves 24a and 24b, the continuous feed negative pressure rotary valve 26a, and the continuous feed positive pressure rotary valve 26b are connected.

<Printing operation of digital printing device>
The printing operation of the digital printing apparatus 1 configured as described above will be described separately when the single-sided printing mode is selected and when the double-sided printing mode is selected.

<Printing operation in single-sided printing mode>
Prior to the operation of the digital printing apparatus 1, the operator operates the print mode selection switch 101 to select the single-sided print mode. When recognizing that the single-sided printing mode is selected via the printing mode selection switch 101, the control device 100 controls the three-way valve 24a so as to close the negative pressure pipe 28c side and open the negative pressure pipe 28b side. The three-way valve 24b is controlled so as to close the 29c side and open the positive pressure pipe 29b side.

  When the three-way valve 24a closes the negative pressure pipe 28c side and opens the negative pressure pipe 28b side, the negative pressure pipe 28a, the three-way valve 24a, the negative pressure pipe 28b, the negative pressure pipe 28d, the negative pressure rotary valve 26a for continuous feeding, and the negative pressure pipe 28e are passed through. Thus, a continuous feed negative pressure flow path is formed in which the negative pressure from the negative pressure source 25a is applied to the first suction 23a and the second suction 23b of the soccer device 23 during continuous feeding of the sheet S1.

  When the three-way valve 24b closes the positive pressure pipe 29c side and opens the positive pressure pipe 29b side, the positive pressure pipe 29a, the three-way valve 24b, the positive pressure pipe 29b, the positive pressure pipe 29d, the continuous feeding positive pressure rotary valve 26b and the positive pressure pipe 29e are passed through. Thus, a positive pressure flow path for continuous sheet feeding is formed in which the positive pressure from the positive pressure source 25b is applied to the first suction 23a and the second suction 23b of the soccer device 23 when the sheet S1 is continuously fed.

  In this way, the three-way valves 24a and 24b switch the negative pressure source 25a and the positive pressure source 25b to the soccer device 23 to the first connection state in which they are connected without the intermittent feeding rotary valve 27.

  As shown in FIG. 5, the control apparatus 100 supplies the same number of sheets S1 as the number of the printing cylinder holding nail devices 33a, 33b, 33c provided in the printing cylinder 33 during one rotation of the printing cylinder 33. In other words, the negative of the first suction 23a and the second suction 23b at each timing (cycle) at which the gripping claw devices 33a, 33b, 33c in the printing cylinder 33 and the gripping claw device 32a of the feeding-side transfer cylinder 32 face each other. The opening / closing of the negative pressure rotary valve 26a for continuous feeding is controlled based on detection signals (detected values of the mechanical phase and the mechanical speed) from the rotary encoder 103 so that suction from the pressure source 25 is performed. In this way, supplying the sheet S1 so that all the printing cylinder holding claw devices 33a, 33b, and 33c of the printing cylinder 33 hold the sheet S1 is called continuous feeding (continuous feeding), and continuous feeding in continuous feeding. The opening / closing cycle of the negative pressure rotary valve 26a for feeding is referred to as a first cycle.

  The first suction 23a and the second suction 23b of the sheet feeding device 2 periodically perform the feeding operation of feeding the sheet S1 to the feeder board FB in the first cycle, and the negative pressure rotary valve 26a for continuous feeding and The sheet S1 of the stacking table 21 is supplied to the feeder board FB in the first cycle by the combination with the opening / closing operation in the first cycle of the continuous pressure positive pressure rotary valve 26b.

  That is, in the section (t1 to t2, t3 to t4, t5 to t6, t7 to t8,...) In which the negative pressure rotary valve 26a for continuous feeding is in the “open” state, the first suction 23a and the first suction 23a of the soccer device 23. The sheet S1 is sucked by the two suctions 23b and conveyed to the feeder board FB, and the continuous feeding negative pressure rotary valve 26a is in the “closed” state (t2 to t3, t4 to t5, t6 to t7, t8 to t9). ,..., The soccer device 23 returns from the feeder board FB to the loading platform 21.

  When the negative pressure rotary valve 26a for continuous feeding is in an “open” state at the timing of the time point t1, the negative pressure source 25a and the soccer device 23 communicate with each other via the three-way valve 24a, and therefore the negative pressure from the negative pressure source 25a. By the action, the first suction 23a and the second suction 23b suck the sheet S1 on the stack 21. After the sheet S1 adsorbed by the first suction 23a and the second suction 23b is conveyed to the feeder board FB in the section from the time point t1 to the time point t2, the negative pressure rotary valve 26a for continuous feeding is closed at the timing of the time point t2. Therefore, the negative pressure action from the negative pressure source 25a on the sheet S1 is released.

  At the timing of time t2, the negative pressure rotary valve 26a for continuous paper feeding is in a “closed” state, and the negative pressure action from the negative pressure source 25a is released. The pressure rotary valve 26b is set to the “open” state. As a result, the continuous feeding positive pressure rotary valve 26b is temporarily opened, so that the positive pressure from the positive pressure source 25b is applied to the sheet S1 adsorbed by the first suction 23a and the second suction 23b of the soccer device 23. Make it work.

  Thus, the sheet S1 is reliably released from the suction by the first suction 23a and the second suction 23b by the positive pressure action from the positive pressure source 25b, and the sheet S1 is fed onto the feeder board FB.

  The feeding of the sheet S1 to the feeder board FB in the section from the time point t1 to the time point t3 described above is similarly performed in the sections t3 to t4, t5 to t6, t7 to t8,. Is continuously supplied. The continuous feeding positive pressure rotary valve 26b is in the “open” state at the timing when the continuous feeding negative pressure rotary valve 26a is in the “closed” state, and the cycle is the same as the first cycle. It is.

  The sheet S1 conveyed by the feeder board FB is conveyed toward the sheet feeding side transfer cylinder 32 by the swing of the swing device 31f after the leading end is held by the gripping claw device of the swing device 31f. The leading end of the sheet S1 is replaced by the holding claw device 32a of the transfer cylinder 32.

  The sheet S1 conveyed by the feeder board FB is held by the gripping claw device of the swing device 31f and then oscillated toward the sheet feeding side transfer cylinder 32. The sheet S1 is held by the sheet feeding side transfer cylinder 32. The leading end of the sheet S1 is replaced by the nail device 32a.

  The sheet S1 conveyed along with the rotation of the sheet feeding side transfer cylinder 32 is transferred from the gripping claw device 32a of the sheet feeding side transfer cylinder 32 to the printing cylinder holding claw device 33a to 33a of the printing cylinder 33 at the contact portion with the printing cylinder 33. After the tip is replaced by any of 33c, it is conveyed along with the rotation of the printing cylinder 33. At this time, the entire surface of the sheet S1 is adsorbed to the support surfaces 33d to 33f of the printing cylinder 33 through the plurality of suction holes in the printing cylinder 33 and closely contacts the support surfaces 33d to 33f.

  Digital printing processing is performed on the surface of the sheet S <b> 1 conveyed by the printing cylinder 33 by ejecting fine droplets of ink from the inkjet nozzle heads 34 a to 34 d of the inkjet nozzle portion 34. Since the sheet S <b> 1 is in close contact with the support surfaces 33 d to 33 f of the printing cylinder 33, the sheet S <b> 1 is conveyed in a state where a minute gap between the ink jet nozzle heads 34 a to 34 d is maintained. By maintaining this minute interval, the ejected ink can land on the sheet S1 with high accuracy, and high-quality printing can be performed.

  The sheet S1 that has been printed by the inkjet nozzle unit 34 passes between the printing cylinder 33 and the ink drying lamp 35, and is irradiated with light from the ink drying lamp 35, whereby the ink on the sheet S1 is dried. . Thereafter, the sheet S1 is conveyed to the first paper discharge side transfer cylinder 36.

  As shown in FIG. 6, in the contact portion between the printing cylinder 33 and the first paper discharge side transfer cylinder 36, the print cylinder holding nail devices 33 a to 33 c of the printing cylinder 33 hold the first paper discharge side transfer cylinder 36. The leading end of the sheet S1 is replaced with the nail device 36a. Thereafter, as shown in FIG. 7, the sheet S <b> 1 held by the gripping claw device 36 a of the first paper discharge side transfer drum 36 is transferred to the first paper discharge side transfer drum 36 and the second paper discharge side transfer drum 37. At the contact portion, the gripper claw device 36a of the first paper discharge side transfer drum 36 is replaced with the gripper claw device 37a of the second paper discharge side transfer drum 37.

  In the single-sided printing mode, the holding claw device 37a of the second discharge side transfer cylinder 37 releases the holding of the leading edge of the sheet S1 at the contact portion between the second discharge side transfer cylinder 37 and the paper take-up cylinder 38. At the same time, the holding claw device 38a of the paper take-up cylinder 38 holds the leading end of the sheet S1, and the holding is changed. As a result, the sheet S1 is transferred from the second delivery side transfer cylinder 37 to the paper take-up cylinder 38 and conveyed.

  The sheet S1 that has been replaced by the paper take-up cylinder 38 is released from being held by the holding claw device 38a at the timing when the holding claw device 38a of the paper take-up cylinder 38 is positioned above the delivery belt 40 and placed on the delivery belt 40. It is done.

  The sheet S1 placed on the delivery belt 40 is conveyed along with the travel of the delivery belt 40, and the sheet S1 whose surface is subjected to digital printing processing is discharged onto the stacking table 41.

<Printing operation in duplex printing mode>
On the other hand, when the control device 100 recognizes that the operator has selected the duplex printing mode via the print mode selection switch 101, the control device 100 controls the three-way valve 24a so as to close the negative pressure pipe 28b side and open the negative pressure pipe 28c side. At the same time, the three-way valve 24b is controlled so that the positive pressure pipe 29b side is closed and the positive pressure pipe 29c side is opened.

  When the three-way valve 24a closes the negative pressure pipe 28b side and opens the negative pressure pipe 28c side, the negative pressure pipe 28a, the three-way valve 24a, the negative pressure pipe 28c, the intermittent feeding rotary valve 27, the negative pressure pipe 28d, and the continuous feeding negative pressure rotary For intermittent sheet feeding, the negative pressure from the negative pressure source 25a is applied to the first suction 23a and the second suction 23b of the soccer device 23 every other time via the valve 26a and the negative pressure pipe 28e when the sheet S1 is intermittently fed. A negative pressure channel is formed.

  When the three-way valve 24b closes the positive pressure pipe 29b side and opens the positive pressure pipe 29c side, the positive pressure pipe 29a, the three-way valve 24b, the positive pressure pipe 29c, the intermittent feed rotary valve 27, the positive pressure pipe 29d, and the continuous feed positive pressure rotary For intermittent sheet feeding, the positive pressure from the positive pressure source 25b is applied to the first suction 23a and the second suction 23b of the soccer device 23 every other time via the valve 26b and the positive pressure pipe 29e during continuous sheet feeding. A positive pressure flow path is formed.

  In this way, the three-way valves 24a and 24b switch the negative pressure source 25a and the positive pressure source 25b to the soccer device 23 to the second connection state in which they are connected via the intermittent feed rotary valve 27.

  As shown in FIG. 8, the control device 100 has the same timing as in the case of continuous feeding, that is, the printing cylinder holding claw devices 33 a to 33 c in the printing cylinder 33 and the holding claw device 32 a in the feeding side transfer cylinder 32. Detection signals (detection of machine phase and machine speed) from the rotary encoder 103 so that the valves become “open”, “open”, “open”, “open”,... At the opposite timing (first period). Value) is controlled to open and close the negative pressure rotary valve 26a for continuous feeding, and the timing at which the sheet S1 is supplied at every other timing with respect to the timing of continuous feeding, that is, the negative pressure rotary for continuous feeding. The valve of the intermittent sheet feeding rotary valve 27 is “open”, “closed” for each cycle (sections t1 to t3, t3 to t5, t5 to t7, t7 to t9,...) Of the valve 26a. Open "," closed ", ..., and controls the opening and closing of the rotary valve 27 for the intermittent feeding on the basis of a detection signal from the rotary encoder 103 (detection value of the mechanical phase and machine speed) so. That is, the open / close cycle of the intermittent feed rotary valve 27 (sections t1 to t5, t5 to t9,...) Is twice the cycle of the continuous feed negative pressure rotary valve 26a.

  In this way, supplying the sheet S1 so that the printing cylinder holding claw devices 33a, 33b, and 33c of the printing cylinder 33 hold the sheet S1 every other time is called intermittent sheet feeding (intermittent feeding), and intermittent sheet feeding is performed. The opening / closing cycle of the intermittent sheet feeding rotary valve 27 is referred to as a second cycle.

  In the case of intermittent sheet feeding, the first suction 23a and the second suction 23b of the sheet feeding device 2 perform a conveying operation of sending the sheet S1 to the feeder board FB in the first cycle, and the negative pressure rotary valve 26a for continuous feeding and The continuous feed positive pressure rotary valve 26b also opens and closes in the first cycle. However, since the intermittent feed rotary valve 27 opens and closes in the second cycle, the first suction 23a and the second suction 23b have a second opening and closing operation. A negative pressure and a positive pressure act in two cycles.

  Specifically, as shown in FIG. 8, the intermittent sheet feeding rotary valve 27 is controlled to be in the “open” state in the section from time t1 to time t3 and in the section from time t5 to time t7.

  When the intermittent feed rotary valve 27 is in the “open” state, the continuous feed negative pressure rotary valve 26a is in the “open” state, and the continuous feed positive pressure rotary valve 26b is in the “closed” state, that is, In the section from the time point t1 to the time point t2, the negative pressure source 25a and the soccer device 23 communicate with each other via the three-way valve 24a and the intermittent sheet feeding rotary valve 27. Therefore, the first suction operation is performed by the negative pressure action from the negative pressure source 25a. 23a and the second suction 23b suck the sheet S1 on the stacking table 21 and convey it to the feeder board FB.

  Thereafter, after the sheet S1 adsorbed by the first suction 23a and the second suction 23b is conveyed to the feeder board FB in the section from time t1 to time t2, the intermittent feeding rotary valve 27 is opened at the timing of time t2. However, since the negative pressure rotary valve 26a for continuous feeding is in the “closed” state, the negative pressure action from the negative pressure source 25a on the sheet S1 is released.

  At the timing of time t2, the negative pressure rotary valve 26a for continuous paper feeding is in a “closed” state, and the negative pressure action from the negative pressure source 25a is released. While in the “open” state, the continuous feed positive pressure rotary valve 26b is temporarily placed in the “open” state. As a result, the continuous feeding positive pressure rotary valve 26b is temporarily opened, so that the positive pressure from the positive pressure source 25b is applied to the sheet S1 adsorbed by the first suction 23a and the second suction 23b of the soccer device 23. The operation is performed via the intermittent feed rotary valve 27 and the continuous feed positive pressure rotary valve 26b.

  Thus, the sheet S1 is reliably released from the suction by the first suction 23a and the second suction 23b by the positive pressure action from the positive pressure source 25b, and the sheet S1 is fed onto the feeder board FB.

  On the other hand, as shown in FIG. 8, the intermittent sheet feeding rotary valve 27 is controlled to be in the “closed” state in the section from time t3 to time t5 and in the section from time t7 to time t9. As a result, the air communication between the negative pressure source 25a and the continuous feeding negative pressure rotary valve 26a and between the positive pressure source 25b and the continuous feeding positive pressure rotary valve 26b is cut off.

  In the section from the time point t3 to the time point t4, the negative pressure rotary valve 26a for continuous paper feeding is in the “open” state, but the rotary valve 27 for intermittent paper feeding is in the “closed” state. The communication with the soccer device 23 is cut off by the intermittent feeding rotary valve 27, and no negative pressure acts on the first suction 23a and the second suction 23b from the negative pressure source 25a, and therefore the first suction 23a. The second suction 23b performs an operation of transporting the sheet S1 of the stacking table 21 to the feeder board FB without sucking the sheet S1.

  At the timing of time t4, the negative pressure rotary valve 26a for continuous paper feeding is in a “closed” state, and the positive pressure rotary valve 26b for continuous paper feeding is temporarily in an “open” state. Since the "closed" state is maintained, the communication between the positive pressure source 25a and the soccer device 23 is cut off by the intermittent paper feeding rotary valve 27, and the first suction 23a and the second suction are discharged from the positive pressure source 25b. No positive pressure acts on the suction 23b.

  Thus, the first suction 23a and the second suction 23b are adsorbing the sheet S1 in the section from the time point t3 to the time point t5 where the rotary valve 27 for intermittent sheet feeding is in the “closed” state, and in the section from the time point t7 to the time point t9. The sheet S1 on the stacking table 21 is not supplied to the feeder board FB because an operation for conveying the sheet to the feeder board FB is performed in the absence of the sheet.

  As a result, the sheet S1 on the loading table 21 is supplied to the feeder board FB in the section from time t1 to time t3, not supplied to the feeder board FB in the section from time t3 to time t5, and in the section from time t5 to time t7. Every other sheet S1 is intermittently supplied to the feeder board FB so that it is supplied and not supplied in the section from the time point t7 to the time point t9.

  In this way, as in the single-sided printing mode, the negative pressure via the intermittent feed rotary valve 27 is controlled while controlling the opening and closing of the negative feed rotary valve 26a for continuous feed and the positive pressure rotary valve 26b for continuous feed. By switching between the negative pressure and the positive pressure on the sheet S1 from the pressure source 25a and the positive pressure source 25b every other sheet, intermittent paper feeding in the duplex printing mode can be executed.

  The sheet S1 sent to the feeder board FB by the soccer device 23 is delivered to the printing cylinder 33 via the swing device 31f and the sheet feeding side transfer cylinder 32 as in the single-sided printing mode, but the sheet S1 is intermittently fed. Since the paper is fed at the paper timing, the printing cylinder holding claw devices 33a to 33c of the printing cylinder 33 receive every other new sheet S1 conveyed from the sheet feeding side transfer cylinder 32.

  Thereafter, the sheet S1 is conveyed to the inkjet nozzle portion 34, and printing for the surface is performed on one surface (front surface) thereof. Here, the control device 100 performs printing on a new sheet S1 held every other one of the printing cylinder holding nail devices 33a to 33c of the printing cylinder 33, and the printing cylinder holding nail that does not hold the sheet S1. The inkjet nozzle heads 34a to 34d of the inkjet nozzle portion 34 are controlled so that printing is not performed on the support surfaces 33d to 33f corresponding to the devices 33a to 33c.

  In the double-sided printing mode, the sheet S1 printed on the surface by the ink jet nozzle unit 34 is not delivered from the second paper discharge side transfer cylinder 37 to the paper take-up cylinder 38, but before-inversion double cylinder 39. Is passed on.

  As described above, in the case of the duplex printing mode, when printing is performed on the front surface but printing is not performed on the other surface (back surface), the control device 100 causes the second discharge side to be printed. In the contact portion between the transfer drum 37 and the paper take-up drum 38, the claw of the gripper claw device 37a of the second discharge-side transfer drum 37 is not opened but is closed, that is, the leading end of the sheet S1 is held. At the same time, the claw of the gripping claw device 38a of the paper drum 38 is maintained without being closed.

  As a result, the sheet S1 is conveyed from the second discharge side transfer drum 37 to the paper take-up drum 38 without being replaced by the pre-inversion double drum 39. The claw of the gripping claw device 39a of the pre-reverse double cylinder 39 is closed at the contact portion between the second paper discharge side transfer cylinder 37 and the pre-reverse double cylinder 39 to hold the leading edge of the sheet S1, and the second paper discharge The nail of the gripping claw device 37a of the side transfer cylinder 37 is opened to release the holding of the leading edge of the sheet S1, and as shown in FIG. The leading end of the sheet S1 is replaced by 39 holding claw devices 39a.

  As shown in FIG. 9, the sheet S1 conveyed along with the rotation of the pre-reverse double cylinder 39 swings the reverse swing device 31b from the delivery position indicated by the solid line to the reception position indicated by the broken line, and the rear end of the sheet S1. Is held by the holding claw device 31bt of the reversing swing device 31b, and at the same time, the holding of the double cylinder 39 before reversing to the leading end of the sheet S1 by the holding claw device 39a is released.

  As shown in FIG. 10, the sheet S1 is conveyed toward the printing cylinder 33 with the trailing edge at the top by the swing of the reverse swing device 31b from the receiving position indicated by the broken line to the delivery position indicated by the solid line, and the reverse swing device 31b. The rear end of the sheet S1 in the reversed state is switched from the gripper nail device 31bt to any of the print cylinder gripper nail devices 33a to 33c of the printing cylinder 33.

Here, the printing cylinder holding claw devices 33a to 33c of the printing cylinder 33 hold every other new sheet S1 conveyed from the sheet feeding side transfer cylinder 32, but the reverse swing device 31b is a new one. Positioned at the delivery position at a timing facing the printing cylinder holding claw devices 33a to 33c that do not hold the sheet S1, and receives the rear end of the sheet S1 from the holding claw device 31bt of the reverse swing device 31b to the printing cylinder holding claw devices 33a to 33c. hand over. As a result, the front and back of the new sheet S1 delivered from the paper feeding side transfer cylinder 32 and the front and back reversal device 31bt of the reversing swing device 31b are transferred to the print cylinder holding claw devices 33a to 33c of the printing cylinder 33. The sheet S1 in the state is held alternately and conveyed to the ink jet nozzle unit 34.

  Note that the timing at which the sheet S1 is delivered again to the printing cylinder 33 by the reversing swing device 31b is that the soccer device 23 intermittently feeds every other sheet S1 by the intermittent feed rotary valve 27. This timing is opposite to the printing cylinder gripping claw devices 33a, 33b, 33c of the printing cylinder 33 that does not hold the new sheet S1 conveyed from the transfer cylinder 32, so that the paper supply side transfer cylinder 32 is moved from the soccer device 23 to the feeding cylinder 32. Thus, the new sheet S1 conveyed every other sheet and the sheet S1 in the reversed state conveyed from the reversing swing device 31b for back surface printing do not interfere with each other.

  At this time, the sheet S1 in the reverse state, which has been transferred from the gripper device 31bt of the reversing swing device 31b, has a surface that has already been subjected to digital printing processing by the inkjet nozzle unit 34 (surface that has been subjected to digital printing processing). In contact with the support surfaces 33d, 33e, and 33f of the sheet S1, and the rear surface of the sheet S1 is exposed (surface not yet processed by digital printing), and the rear end of the sheet S1 is held by the printing cylinder holding nail devices 33a to 33c of the printing cylinder 33. In other words, the sheet S1 is conveyed in an inverted state, and a digital printing process is performed on the back surface of the sheet S1 by the inkjet nozzle unit 34.

  Here, the control device 100 performs reverse-side printing on the single-side printed sheet S1 that has been printed on one side and has been transferred from the gripper device 31bt of the reverse swing device 31b based on the detection signal from the rotary encoder 103. The inkjet nozzle heads 34a to 34d of the inkjet nozzle section 34 are controlled so that the surface printing is performed on the new sheets S1 held every other gripper device 33a to 33c of the printing cylinder 33. . Thereby, the inkjet nozzle heads 34a to 34d efficiently perform the printing for the front surface and the printing for the back surface alternately corresponding to the new sheet S1 alternately held on the printing cylinder 33 and the sheet S1 in the reverse state. be able to.

  Thereafter, the sheet S1 printed on the back side is printed on the first discharge side transfer drum 36, the second discharge side transfer drum 37, and the paper drum 38 in the same manner as in the single-sided printing mode. Then, the paper is discharged from the delivery belt 40 to the loading table 41 of the paper discharge device 4.

<Other embodiments>
In the above-described embodiment, the case where the four-color ink-jet nozzle part 34 is used has been described. However, the present invention is not limited to this, and an ink-jet nozzle head part having more or less colors is used. It may be used.

  In the above-described embodiment, the case where the paper sheet S1 is used as a conveyance target has been described. However, the present invention is not limited thereto, and a film sheet may be used as a conveyance target. In short, it is not necessary to use paper if it is in sheet form.

  Further, in the above-described embodiment, the case where the printing cylinder 33 having a triple cylinder is used as the printing cylinder has been described. However, the present invention is not limited to this, and other cylinders such as a double cylinder, a quadruple cylinder, and the like. Printing cylinders of various sizes may be used.

  Furthermore, in the above-described embodiment, the intermittent feed rotary valve 27, the continuous feed negative pressure rotary valve 26a, and the continuous feed positive pressure rotary valve 26b are each driven to open and close by a dedicated motor. Although the present invention is not limited to this, the present invention is not limited to this, and is mechanically coupled to a machine motor that rotationally drives various cylinders of the machine so that opening and closing of the valve is driven by the machine motor. May be.

  Further, in the above-described embodiment, the case where the digital printing process is performed by the ink jet method has been described. However, the present invention is not limited to this, and the digital printing process is performed by various other methods such as a toner method. It may be.

  DESCRIPTION OF SYMBOLS 1 ... Digital printing apparatus, 2 ... Paper feeding apparatus (sheet supply part), 3 ... Digital printing unit, 4 ... Paper discharge apparatus, 21, 41 ... Loading platform, 23 ... Soccer apparatus, 24a, 24b ... Three-way valve (switching means) ), 25a ... Negative pressure source, 25b ... Positive pressure source, 26a ... Negative pressure rotary valve for continuous feeding (negative pressure rotary valve for continuous feeding), 26b ... Positive pressure rotary valve for continuous feeding, 27 ... Intermittent feeding Rotary valve (rotary valve for intermittent supply, switching means), 31b ... reversing swing device (sheet reversing portion), 31f ... swing device, 32 ... paper feed side transfer cylinder, 33 ... printing cylinder, 34 ... inkjet nozzle portion (processing) Part), 35 ... ink drying lamp, 36 ... first paper discharge side transfer cylinder, 37 ... second paper discharge side transfer cylinder, 38 ... paper take-up cylinder, 39 ... double cylinder before reversal (sheet reversing part), 40 …delivery Belt, 100 ... controller, 101 ... print mode selection switch, 103 ... rotary encoder, FB ... feeder board, S1 ... sheet.

Claims (2)

A printing cylinder that holds and conveys the sheet;
A processing unit for performing a digital printing process on a sheet conveyed by the printing cylinder;
A sheet reversing unit that reverses the front and back of the sheet digitally processed by the processing unit and passes the sheet to the printing cylinder;
A sheet supply unit for supplying the sheet to the printing cylinder,
The sheet supply unit
A negative pressure source,
A soccer device connected to the negative pressure source and supplying a sheet to the printing cylinder;
A switching means for switching the action of negative pressure on the soccer device in a second period longer than a first period in which sheets are intermittently supplied to the printing cylinder when supplying sheets intermittently ;
A negative pressure rotary valve for continuous supply that is provided between the switching means and the soccer device, and connects and disconnects the negative pressure source and the soccer device at the first period ;
The soccer device operates in the first period;
The second period is twice the first period,
The switching means is
An intermittent supply rotary valve that is provided between the negative pressure source and the soccer device, and connects and disconnects the negative pressure source and the soccer device in the second period;
A first connection state that is provided between the negative pressure source and the intermittent supply rotary valve, and connects the negative pressure source and the soccer gear without going through the intermittent supply rotary valve, and the negative pressure source. And a three-way valve that switches to a second connection state in which the soccer device is connected via the intermittent supply rotary valve ,
When the sheet is continuously supplied, the negative pressure from the negative pressure source is applied to the soccer device via the negative pressure rotary valve for continuous supply in the first connection state, and when the sheet is intermittently supplied, The three-way valve is switched to apply a negative pressure from the negative pressure source to the soccer device through the second connection state and the intermittent supply rotary valve and the continuous supply negative pressure rotary valve. A sheet supply device. A printing cylinder that holds and conveys the sheet;
A processing unit for performing a digital printing process on a sheet conveyed by the printing cylinder;
A sheet reversing unit that reverses the front and back of the sheet digitally processed by the processing unit and passes the sheet to the printing cylinder;
A sheet supply unit for supplying the sheet to the printing cylinder;
With
The sheet supply unit
A negative pressure source,
A soccer device connected to the negative pressure source and supplying a sheet to the printing cylinder;
A switching means for switching the action of negative pressure on the soccer device in a second period longer than a first period in which sheets are intermittently supplied to the printing cylinder when supplying sheets intermittently;
A negative pressure rotary valve for continuous supply, which is provided between the switching means and the soccer device, and connects and disconnects the negative pressure source and the soccer device at the first cycle;
With
The soccer device operates in the first period;
The second period is twice the first period,
The switching means is
An intermittent supply rotary valve that is provided between the negative pressure source and the soccer device, and connects and disconnects the negative pressure source and the soccer device in the second period;
A first connection state that is provided between the negative pressure source and the intermittent supply rotary valve, and connects the negative pressure source and the soccer gear without going through the intermittent supply rotary valve, and the negative pressure source. And a three-way valve that switches to a second connection state in which the soccer device is connected via the intermittent supply rotary valve ,
When the sheet is continuously supplied, the negative pressure from the negative pressure source is applied to the soccer device via the negative pressure rotary valve for continuous supply in the first connection state, and when the sheet is intermittently supplied, The three-way valve is switched to apply a negative pressure from the negative pressure source to the soccer device through the second connection state and the intermittent supply rotary valve and the continuous supply negative pressure rotary valve,
The sheet supply unit
A sheet supply apparatus comprising: a positive pressure source that applies a positive pressure to the soccer device .

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