JP5490282B2 - Paper discharge device for printing device - Google Patents

Description

  The present invention relates to a paper discharge device for a printing device that discharges printed printing paper.

  In the printing apparatus, when the printed printing paper is discharged, a phenomenon that the leading edge of the printed printing paper hangs downward or a curling phenomenon (hereinafter referred to as a curling phenomenon) occurs. If nothing is done, the print image surface of the print paper loaded on the paper receiver first will rub against the leading edge of the next print paper and the print image of the previous print paper will be destroyed. There arises a problem and a problem that the printing paper is deteriorated.

An example of a paper discharge device of a printing apparatus that solves such a problem is disclosed in Patent Document 1.
The paper discharge device disclosed in Patent Document 1 includes a paper discharge passage that sucks a printed print paper and guides it to a paper receiving portion (discharge tray) by an endless belt, and is perpendicular to the conveyance direction of the print paper. A pair of movable ridge members in the left-right direction are arranged in the middle of the paper discharge passage so as to be substantially movable in the vertical direction, and the pair of movable ridge members are driven in the vertical direction according to the size of the printing paper. A cam-type driving means, and the driving means automatically changes the height position of the movable bulging member according to the size of the printing paper to give an appropriate amount of U-shaped curve to the printing paper. ing. Further, the printing paper is stacked from the paper discharge device to the paper receiving portion by utilizing the momentum of conveyance.

  According to this configuration, the movable protruding member is driven according to the size of the printing paper, and an appropriate amount of U-shaped curve is always given to the printing paper, so that the printing paper in the paper discharge direction (front-rear direction) The apparent rigidity can be increased to prevent the tip of the printed printing paper from drooping downward, and the above-described problem that the printed image of the previous printing paper is destroyed and the stacking state of the printing paper are It avoids the problem of getting worse.

Japanese Patent Laid-Open No. 6-239000

  However, in the paper discharge device of the printing apparatus disclosed in Patent Document 1, the movable bulging member rubs against the printing paper in order to give the printing paper an appropriate amount of U-shaped curvature by the movable bulging member. With the printed paper, the printed image may be destroyed. Further, the paper discharge device may cause a curl phenomenon in the air to curl due to a curling phenomenon when the printing paper is blown to the paper receiving portion by using the momentum of conveyance, and the printing paper may be unstacked.

  Accordingly, the present invention can avoid the printing image on the printing paper from being crushed by rubbing the printing paper, can avoid the curling phenomenon, and can be discharged from the printing apparatus that can improve the stacking state at the paper receiving portion. The object is to provide an apparatus.

In order to solve the above-described problem, a paper discharge device for a printing apparatus according to the present invention is a paper discharge device for a printing device that discharges printed print paper to a paper receiving portion on which the print paper is stacked. A conveying device that sucks the printing paper while being conveyed by the conveying belt and guides the printed printing paper upward in the downstream direction in the conveying direction,
Disposing a discharge device that drops the printed paper in a downward posture, which has been transported by the transport device, onto the paper receiver substantially above the paper receiver,
The discharge device is arranged in parallel with a conveyance direction of the printed printing paper, and a pair of suction conveyance belt devices that convey the printed printing paper that has been conveyed while sucking, and the pair of suction conveyance belts A rotation device that rotates the apparatus so that the suction surfaces face each other with respect to the transport direction, and a detection device that detects the leading edge of the printed printing paper in the downstream portion,
When the detection device detects the leading edge of the printed paper, the discharge device rotates the pair of suction conveyance belt devices so that the suction surfaces face each other in the conveyance direction. It is characterized by.

  As described above, according to the present invention, the printed printing paper is conveyed by the conveying belt while being sucked by the conveying device, so that the printing surface of the printing paper is not rubbed by the roller or the like, that is, the printed image is destroyed. It can be transported without any problems, and the curled phenomenon can be avoided by guiding the printed printing paper to the upper part of the paper receiving part and dropping it onto the paper receiving part by the discharge device, and improving the stacking condition of the printing paper in the paper receiving part. Can do.

1 is an overall configuration diagram of an ink jet printing apparatus including a paper discharge device according to an embodiment of the present invention. It is a figure which shows the conveying apparatus of the paper discharge apparatus, (a) is side sectional drawing, (b) is a top view, (c) is a principal part perspective view. It is a figure which shows the discharge apparatus of the paper discharge apparatus in the embodiment, (a) is side sectional drawing, (b) is a bottom view, (c) is front sectional drawing, (d) is operation explanatory drawing. It is a figure which shows the discharge apparatus of the paper discharge apparatus in a reference example, (a) is side sectional drawing, (b) is a top view, (c) is a bottom view. It is a figure which shows the discharge apparatus of the paper discharge apparatus in another reference example, (a) is side sectional drawing, (b) is AA arrow sectional drawing of (a). It is a figure which shows the discharge apparatus of the paper discharge apparatus in another reference example, (a) is side surface sectional drawing, (b) is BB arrow sectional drawing of (a), (c) is operation explanatory drawing. It is a figure which shows the discharge apparatus of the paper discharge apparatus in another reference example, (a) is side surface sectional drawing, (b) is CC sectional view taken on the line of (a), (c) is operation explanatory drawing. It is a figure which shows the discharge apparatus of the paper discharge apparatus in another reference example, (a) is side sectional drawing, (b) is a top view, (c) is a bottom view.

Hereinafter, an embodiment in which a paper discharge device of the present invention is used in an ink jet printing apparatus will be described with reference to the drawings.
FIG. 1 is an overall configuration diagram of an ink jet printing apparatus 11. The ink jet printing apparatus 11 includes a paper feed mechanism section 12, a paper transport mechanism section 13, an image forming section (printing apparatus main body section) 14, a paper discharge apparatus 15, The paper receiving mechanism 16 is configured.

  The paper feed mechanism unit 12 includes a paper feed base 22 on which the print paper 21 that is a recording medium is stacked, a paper feed roller 23 for feeding the print paper 21 from the paper feed base 22 one by one, and a staging base 24. The paper transport mechanism unit 13 includes upper and lower transport rollers 25 for supplying the print paper 21 fed from the paper feed mechanism unit 12 to the image forming unit 14 and forms an image of the print paper 21 one by one. To the unit 14.

  The image forming unit 14 is disposed above the conveyance guide, a conveyance guide (not shown) that forms the conveyance surface of the printing paper 21, a conveyance roller 27 that conveys (moves) the printing paper 21 in the conveyance direction A, and the like. A plurality of line-type recording heads 28 are provided. While the supplied printing paper 21 is guided by a conveyance guide and conveyed by a conveyance roller 27, water-based ink is printed from the plurality of line-type recording heads 28 by an ink jet method. Is printed on the paper. Further, cap means 29 are arranged below the respective line type recording heads 28, and the cap means 29 respectively correspond to the respective line type recording heads 28 and are vertically moved by an elevating device (not shown). The cap 30 is configured to be movable up and down, a suction pump 31, and a waste liquid tank 32. The printing paper 21 printed by the image forming unit 14 is discharged by the paper discharge device 15 and is stacked on the paper receiving mechanism unit 16.

The paper receiving mechanism unit 16 is stacked on the paper receiving unit 35 for stacking the printing paper 21 discharged by the paper discharge device 15, the lifting device 36 for moving the paper receiving unit 35 up and down, and the paper receiving unit 35. A height detection device (not shown) for detecting the height of the printed paper 21 is provided, and a discharge device 43 of the paper discharge device 15 to be described later according to the height of the print paper 21 detected by the height detection device. The lifting / lowering device 36 lifts and lowers the paper receiving portion 35 so that the distance from the surface of the printing paper 21 stacked on the paper receiving portion 35 is constant. The elevating device 36 is constituted by, for example, a jack-up mechanism, and the distance is shortened until the printing paper 21 falling from the discharge device 43 described later reaches the surface of the printing paper 21 stacked on the paper receiving portion 35. Is made as short as possible.
[Discharge device 15]
The paper discharge device 15 will be described in detail.

  The paper discharge device 15 includes a plurality of (four in the figure) transport devices 41 arranged in series in the transport direction A, a transport guide 42 for the printing paper 21 disposed between the transport devices 41, and a discharge device 43. Has been.

"Conveyor 41"
The four transport devices 41 are a first transport device 41A that transports the printing paper 21 discharged from the image forming unit 14 in a horizontal posture with its print surface facing upward, and vertically upward from the downstream end of the first transport device 41A. The second transport device 41B that transports the printing paper 21 transported from the first transport device 41A in a vertical posture, and is disposed above the second transport device 41B and unloaded from the second transport device 41B. The third transport device 41C that transports the printing paper 21 in a vertical posture, and the printing paper 21 that is disposed in the horizontal direction from the downstream end of the third transport device 41C and is unloaded from the third transport device 41C has a printing surface. It is comprised from 4th conveying apparatus 41D conveyed with a horizontal attitude | position facing downward.

  As shown in FIG. 2, each of these transport devices 41 </ b> A to 41 </ b> D forms a transport surface that transports the printing paper 21, and includes a plurality of endless transport belts 45 </ b> A that move the printing paper 21 in the transport direction A. The belt device 45 and a fan (an example of a suction device) 46 that sucks air from a suction port 46 a between the endless transport belt 45 </ b> A of the transport belt device 45, and the supplied printing paper 21 is sucked by the fan 46. Then, the sheet is conveyed in the conveying direction A by the endless conveying belt 45A. Note that the exhaust side of the fan 46 is open, and the air sucked from the suction port 46a is discharged from the opposite side.

  The conveyor belt device 45 includes an upstream driven roller 47A, a downstream drive roller 47B, the plurality of endless belts 45A wound between these rollers 47A and 47B, and a drive shaft of the drive roller 47B ( A pulley 47C attached to the rotation shaft), a drive pulley 48, a drive belt 49 wound between the pulley 47C and the drive pulley 48, and a drive motor 50 connected to the rotation shaft of the drive pulley 48. It is composed of The endless belt 45A is arranged at intervals in a direction perpendicular to the transport direction A. In order to match the level of the upper surface of the endless belt 45A and the transport surface of the printing paper 21, FIG. As shown in c), the rollers 47A and 47B are provided with recesses 47D and 47E corresponding to the thickness of the endless belt 45A, and the endless belt 45A is wound between the recesses 47D and 47E. By driving the drive motor 50, the drive roller 47B is rotated via the drive pulley 48, the drive belt 49, and the pulley 47C, and a plurality of endless belts 45A are rotated.

  The printing paper 21 carried into the first conveyance device 41A with the printing surface facing upward is conveyed by the conveyance devices 41A to 41D and guided by the conveyance guides 42 in the middle. In the transport device 41D of No. 4, the printing surface is in a downward posture, and is guided above the paper receiving mechanism unit 16 (paper receiving unit 35). At this time, the printing surface is conveyed without being rubbed by a roller or the like, that is, the printed image is not broken. Note that the suction allows the printing paper 21 to be transported without falling even if it is in a downward posture.

"Discharge device 43"
When the printing paper 21 with the printing surface facing downward is transported from the fourth transport device 41D, the discharge device 43 causes the printing paper 21 to drop onto the paper receiving portion 35 while suppressing the dropping speed. As shown in FIG. 3, the discharge device 43 is arranged in the transport direction A while sucking the transported print paper 21 at an interval in accordance with the width of the print paper 21 in parallel with the transport direction A of the print paper 21. A pair of suction conveyance belt devices 75 having the suction surface of the printing paper 21 conveyed downward are arranged.

Each suction conveyance belt device 75 includes a perforated endless conveyance belt 76, a fan 77 disposed between the upper and lower endless conveyance belts 76, and a belt rotation motor 78 for rotating the endless conveyance belt 76. I have. In addition, as a rotation device that rotates these suction conveyance belt devices 75 so that the suction surfaces face each other in the conveyance direction A, a rotation shaft 79 disposed before and after the suction conveyance belt device 75, and the rotation shaft A unit rotation motor 80 is provided to turn 79 to the left and right in the conveyance direction A.

A photoelectric sensor 81 for detecting the printing paper 21 is provided at the downstream end.
With this configuration, the fan 77 is always driven, the perforated endless transport belt 76 is always driven by the belt rotating motor 78, and the printing paper 21 transported from the fourth transport device 41D has left and right ends. When the leading end of the printing paper 21 is detected by the photoelectric sensor 71, the lower surfaces (suction surfaces) of the left and right suction conveyance belt devices 75 are opposed to each other by the unit rotation motor 80 for a certain time. As shown in FIG. 7D, the printing paper 21 tends to bow upward, but the printing paper 21 cannot follow this movement and peels off from the suction surface. Since a gap is formed between the printing paper 21 and the endless conveyance belt 76 and air is sucked from the gap, the force for attracting the printing paper 21 is lost (weakened). Although the paper 21 falls naturally, at this time, the printing paper 21 is in a posture similar to a bow, and since there is an ascending airflow due to the air sucked by the fan 77, the dropping speed is suppressed without suddenly falling. And loaded on the paper receiver 35. Further, after a certain time, the unit rotation motor 80 is reversed, the left and right suction conveyance belt devices 75 are returned to their original postures, and the force for attracting the printing paper 21 is recovered, and the printing paper 21 is sucked. Become.
[Function and effect]
With the configuration described above, the present embodiment has the following operational effects.

  The printing paper 21 is fed out one by one from the paper feed table 22 of the paper feed mechanism unit 12 by the paper feed roller 23 and the separating table 24, and is conveyed to the image forming unit 14 by the conveyance roller 25 of the paper conveyance mechanism unit 13. In the image forming unit 14, the printing paper 21 is conveyed by the conveyance roller 27 while being guided by the conveyance guide, and water-based ink is ejected from the plurality of line-type recording heads 28 onto the paper surface by an ink jet method to perform printing. The paper is discharged by the paper device 15 and stacked on the paper receiving mechanism 16.

  In the paper discharge device 15, the printing paper 21 carried into the first transport device 41 </ b> A with the printing surface facing upward is transported downstream of the transport direction A by the transport of the transport devices 41 </ b> A to 41 </ b> D and the transport guide 42 in the middle. In the fourth conveying device 41D, the printing surface is in a downward posture, and is guided upward of the paper receiving mechanism 16 (paper receiving portion 35). At this time, the printing surface is conveyed without being rubbed by a roller or the like, that is, the printed image is not broken. Note that the suction allows the printing paper 21 to be transported without falling even if it is in a downward posture.

In the discharge device 43 in this embodiment, when falling away from the lower surface, it can be stacked on the paper receiving portion 35 without dropping suddenly, and the loading state can be improved.

  As described above, according to the present embodiment, the printed printing paper 21 is conveyed by the endless conveying belt 45A while being sucked by the fans 46 by the conveying devices 41A to 41D, so that the printing surface is a roller or the like. Therefore, the printed image can be conveyed by being pressed against the surface of the endless conveying belt 45A without being rubbed, that is, the printed image can be prevented from being deformed.

A reference example of the discharge device 43 will be described below.
"Reference Example 1"
When the printing paper 21 with the printing surface facing downward is transported from the fourth transport device 41D, the discharge device 43 causes the printing paper 21 to drop onto the paper receiving portion 35 while suppressing the dropping speed. As shown in FIG. 4 , the discharging device 43 has the same basic configuration as the conveying devices 41 </ b> A to 41 </ b> D. That is, the discharge device 43 has a transport belt device 45 that includes a plurality of endless transport belts 45A that form a transport surface for transporting the print paper 21 and move the print paper 21 in the transport direction A.

  The conveyor belt device 45 includes an upstream driven roller 47A, a downstream drive roller 47B, the plurality of endless belts 45A wound between these rollers 47A and 47B, and a drive shaft (rotation) of the drive roller 47B. A pulley 47 </ b> C attached to the shaft), a drive pulley 48, a drive belt 49 wound between the pulley 47 </ b> C and the drive pulley 48, and a drive motor 50 connected to the rotation shaft of the drive pulley 48. It is configured.

  A lower surface exhaust port 51 is provided in the upstream portion and a suction port 52 is provided in the downstream portion at a distance from the lower surface on which the printed printing paper 21 is conveyed. 52 is provided with a fan (an example of a suction device) 53 that sucks air from 52, and a communication passage 54 that guides the air sucked by the fan 53 to the lower surface exhaust port 51, and the air sucked by the fan 53 is provided on the upper surface. An upper surface exhaust port 55 that escapes upward and a shutter device (blocking device) 56 that can block the upper surface exhaust port 55 are provided. A photoelectric sensor (an example of a detection device) 58 that detects the leading edge of the printed printing paper 21 is provided between the lower surface exhaust port 51 and the suction port 52. Further, the shutter device 56 is configured to open or close the upper side of the upper surface exhaust port 55 by sliding the shielding plate in a plane, for example.

  With this configuration, the fan 53 is always driven, air is sucked from the suction port 52, and is exhausted from the upper upper surface exhaust port 55. When the leading edge of the printed printing paper 21 conveyed from the fourth conveying device 41D is detected by the photoelectric sensor 58, the upper surface exhaust port 55 is blocked by the shutter device 56 for a certain period of time, and the fan 53 is blocked. The sucked air is guided to the lower surface exhaust port 51 through the communication passage 54 and is jetted downward. After a certain time, the upper exhaust port 55 is opened by the shutter device 56, and the injection of air from the lower exhaust port 51 is stopped.

  As a result, the printing paper 21 with the printing surface facing downward is conveyed from the fourth conveying device 41D, the leading end reaches between the lower surface exhaust port 51 and the suction port 52, and is detected by the photoelectric sensor 58. Air is blown from the exhaust port 51, that is, from above the printing paper 21 for a certain period of time and starts to fall away from the lower surface of the discharge device 43. At this time, there is an upward air flow due to the air sucked by the fan 53. For this reason, the front side of the printing paper 21 is placed in an upward posture without falling suddenly, and falls to the paper receiving portion 35, the dropping speed is suppressed (controlled), and the paper receiving portion 35 is loaded. . Further, after a certain time, the shutter device 56 operates to open the upper exhaust port 55, and the printing paper 21 is sucked.

  Then, when the printing paper 21 with the printing surface facing downward is conveyed from the fourth conveying device 41D, the leading end reaches between the lower surface exhaust port 51 and the suction port 52, and is detected by the photoelectric sensor 58, Air is blown from the lower surface exhaust port 51, that is, from the upper side of the printing paper 21 for a certain time, falls away from the lower surface of the discharge device 43, and the dropping speed is suppressed, and the paper receiving unit 35 is loaded.

  Further, in the paper receiving mechanism unit 16, the paper receiving unit 35 is moved up and down by the lifting device 36 so that the distance between the discharging device 43 of the paper discharging device 15 and the surface of the printing paper 21 stacked on the paper receiving unit 35 is constant. Is done. Further, the distance between the discharge device 43 of the paper discharge device 15 and the surface of the printing paper 21 loaded on the paper receiving portion 35 is shortened, and the printing paper 21 falling from the discharging device 43 is printed on the paper receiving portion 35. By shortening the time to reach the surface of the paper 21 as much as possible, the falling printing paper 21 is loaded on the paper receiving unit 35 without curling time.

Further, according to this reference example, when the leading end of the printing paper 21 conveyed to the discharge device 43 reaches between the lower surface exhaust port 51 and the suction port 52, air is blown from above for a certain period of time, Although falling starts from the lower surface, there is an upward air flow due to the air sucked by the fan 53 forward at this time, so that the stacking state of the paper receiving portion 35 can be improved without dropping suddenly.

In the present reference example, the shutter device 56 is configured to slide the shielding plates in a plane, but is not limited to such a configuration. For example, the elongated shielding plates are arranged in a plane and the postures of these shielding plates are changed. It is good also as a structure which opens and closes by changing to horizontal and vertical. Further, according to the present embodiment, the endless belt 45A is arranged at a predetermined interval and the printing paper 21 is sucked from the interval. The endless belt 45A is a perforated belt, and printing is performed from this hole. The paper 21 may be sucked.
"Reference Example 2"
The discharging device 43 shown in FIG. 5 is configured to invert the configuration of the conveying device 41 shown in FIG. 2 and convey the printing paper 21 while sucking the printing paper 21 on the lower surface. I will explain. The discharge device 43 is provided with a shutter device 61 for blocking the suction of the printing paper 21 by the fan 46 at the suction port 46a of the fan 46, and a photoelectric sensor 62 for detecting the printing paper 21 at the downstream end. The shutter device 61 is configured, for example, to open or close the suction port 46a by sliding the shielding plate in a plane.

  With this configuration, the fan 46 is always driven, air is sucked from the suction port 46a, and exhausted upward from the opposite side. When the leading end of the printed printing paper 21 conveyed from the fourth conveying device 41D is detected by the photoelectric sensor 62, the suction port 46a is blocked by the shutter device 61 for a certain time, and the printing paper 21 is removed. The adsorbing force is lost, and the printing paper 21 naturally falls. At this time, air is sucked from the side by the fan 46, so that an ascending airflow due to the air sucked by the fan 46 exists around the printing paper 21. For this purpose, the dropping speed is suppressed and the paper receiving portion 35 is loaded without dropping suddenly. After a certain time, the shutter device 61 operates to open the suction port 46a, and the printing paper 21 is sucked.

Also in the discharging device 43 in this reference example, when dropping away from the lower surface, it can be stacked on the paper receiving portion 35 without dropping suddenly, and the loading state can be improved. In the present embodiment, the shutter device 61 is configured to slide the shielding plate in a planar manner. However, the present invention is not limited to such a configuration. For example, the elongated shielding plates are arranged in a plane, and the postures of these shielding plates are arranged. It is good also as a structure which opens and closes by changing to horizontal and vertical. In the present embodiment, the endless belt 45A is arranged at a predetermined interval, and the printing paper 21 is sucked from the interval. The endless belt 45A is a perforated belt, and the printing paper is passed through the hole. 21 may be sucked.
"Reference Example 3"
The discharging device 43 shown in FIG. 6 has a configuration in which the configuration of the conveying device 41 shown in FIG. To explain. The discharge device 43 is disposed between the plurality of endless conveyance belts 45A located below and the fan 46, and the plurality of endless conveyance belts 45A located below are pushed downward to suck the endless conveyance belt 45A and the fan 46. A space expansion device 64 is provided to increase the space between the mouth 46a.

  The gap extending device 64 has an extended portion 65 disposed between the rollers 47A and 47B. The extended portion 65 has a roller 66 that pushes a plurality of endless transport belts 45A positioned below, and a roller 66 A pair of arms 67 that respectively support the rotating shafts 66a at both ends, one end of which is attached at right angles to the rotating shaft 66a, a connecting shaft 68 that connects the other ends of these arms 67, and the connecting shaft 68 can be rotated freely. A pair of bearings 69 to be supported and a motor 70 for rotating the connecting shaft 68 are configured.

A photoelectric sensor 71 for detecting the printing paper 21 is provided at the downstream end.
With this configuration, the fan 46 is always driven, and air is sucked from the suction port 46a and exhausted upward from the opposite side. When the leading edge of the printed printing paper 21 conveyed from the fourth conveying device 41D is detected by the photoelectric sensor 71, the roller 66 is moved by the motor 70 via the connecting shaft 68 and the arm 67 for a certain period of time. The space between the plurality of endless transport belts 45A positioned below and the suction port 46a of the fan 46 is rotated downward, and the air sucked from this space loses the force for adsorbing the printing paper 21 ( However, since the air is sucked from the gap by the fan 46 at this time, there is an upward air flow due to the air sucked by the fan 46 around the print paper 21. The dropping speed is suppressed without being dropped suddenly, and the paper receiving unit 35 is loaded. Further, after a certain time, the motor 70 is rotated reversely, the roller 66 is rotated upward, the intervals between the plurality of endless transport belts 45A located below and the suction ports 46a of the fans 46 are returned, and the printing paper 21 is adsorbed. Power is restored.

Also in the discharging device 43 in this reference example, when dropping away from the lower surface, it can be stacked on the paper receiving portion 35 without dropping suddenly, and the loading state can be improved. In the present embodiment, the endless belt 45A is arranged at a predetermined interval, and the printing paper 21 is sucked from the interval. The endless belt 45A is a perforated belt, and the printing paper is passed through the hole. 21 may be sucked.
“Reference Example 4”
The discharge device 43 shown in FIG. 7 is basically the same as the configuration described above with reference to FIG .

  The gap extending device 64 has an extended portion 65 disposed between the rollers 47A and 47B. The extended portion 65 has a swing bar 90 whose tip can protrude downward from the endless transport belt 45A, and the swing bar 90. A connecting shaft 68 connected to the other end, a pair of bearings 69 that rotatably support the connecting shaft 68, and a motor 70 that rotates the connecting shaft 68 are included. A photoelectric sensor 71 for detecting the printing paper 21 is provided at the downstream end.

  With this configuration, the fan 46 is always driven, and air is sucked from the suction port 46a and exhausted upward from the opposite side. When the leading edge of the printed printing paper 21 conveyed from the fourth conveying device 41D is detected by the photoelectric sensor 71, the swing bar 90 is moved downward via the connecting shaft 68 by the motor 70 for a certain period of time. The gap between the plurality of endless transport belts 45A located below and the printing paper 21 is increased, and the air sucked from this gap loses the force to adsorb the printing paper 21 (weakens). Although the paper 21 naturally falls, the air is sucked by the fan 46 at this time, and therefore, there is a rising air current due to the air sucked by the fan 46 around the printing paper 21, so that the paper 21 does not fall abruptly. The falling speed is suppressed and the paper is loaded on the paper receiver 35. Further, after a certain time, the motor 70 is reversely rotated and the swing bar 90 is rotated upward.

Also in the discharging device 43 in this reference example, when dropping away from the lower surface, it can be stacked on the paper receiving portion 35 without dropping suddenly, and the loading state can be improved. In the present embodiment, the endless belt 45A is arranged at a predetermined interval, and the printing paper 21 is sucked from the interval. The endless belt 45A is a perforated belt, and the printing paper is passed through the hole. 21 may be sucked.
Reference Example 5
The discharge device 43 shown in FIG. 8 is basically the same as the configuration described above with reference to FIG .

  On the lower surface to which the printed printing paper 21 is conveyed, lower surface exhaust ports 51 and 51 are provided in the upstream and downstream portions, a suction port 52 is provided between the lower surface exhaust ports 51 and 51, and the inside Above the suction port 52, a fan (an example of a suction device) 53 that sucks air from the suction port 52, a communication passage 54 that guides the air sucked by the fan 53 to the lower surface exhaust ports 51, 51 are provided. Are provided with an upper surface exhaust port 55 for allowing air sucked by the fan 53 to escape upward and a shutter device (blocking device) 56 that can block the upper surface exhaust port 55.

  With this configuration, the fan 53 is always driven, air is sucked from the suction port 52, and is exhausted from the upper upper surface exhaust port 55. When the leading edge of the printed printing paper 21 conveyed from the fourth conveying device 41D is detected by the photoelectric sensor 58, the upper surface exhaust port 55 is blocked by the shutter device 56 for a certain period of time, and the fan 53 is blocked. The sucked air is guided to the lower surface exhaust ports 51 and 51 through the communication passage 57 and jetted downward. After a certain time, the upper exhaust port 55 is opened by the shutter device 56, and the injection of air from the lower exhaust ports 51, 51 is stopped.

  As a result, when the printing paper 21 with the printing surface facing downward is conveyed from the fourth conveying device 41D and the leading edge is detected by the photoelectric sensor 58, air is emitted from the lower surface exhaust ports 51, 51, that is, from above the printing paper 21. Is sprayed for a certain period of time and starts to fall away from the lower surface of the discharge device 43. At this time, since there is an upward airflow due to the air sucked by the fan 53, the printing paper 21 does not fall abruptly. The front side of the paper is directed upward and falls to the paper receiving portion 35, the dropping speed is suppressed (controlled), and the paper receiving portion 35 is loaded. In addition, after a certain time, the shutter device 56 operates to open the upper surface exhaust port 55, and the printing paper 21 can be sucked.

Also in the discharging device 43 in this reference example, when dropping away from the lower surface, it can be stacked on the paper receiving portion 35 without dropping suddenly, and the loading state can be improved. In the present embodiment, the shutter device 56 is configured to slide the shielding plate in a planar manner. However, the present invention is not limited to such a configuration. It is good also as a structure which opens and closes by changing to horizontal and vertical. In the present embodiment, the endless belt 45A is arranged at a predetermined interval, and the printing paper 21 is sucked from the interval. The endless belt 45A is a perforated belt, and the printing paper is passed through the hole. 21 may be sucked.

DESCRIPTION OF SYMBOLS 11 Inkjet printing apparatus 12 Paper feed mechanism part 13 Paper conveyance mechanism part 14 Image formation part 15 Paper discharge apparatus 16 Paper receiving mechanism part 21 Printing paper 35 Paper reception part 36 Lifting apparatus 41 Conveyance apparatus 42 Conveyance guide 43 Discharge apparatus 45 Conveyance belt Devices 45A, 76 Endless conveyor belt 46, 77 Fan 46a Suction port 51 Lower surface exhaust port 52 Suction port 53 Fan 54 Communication passage 55 Upper surface exhaust port 56, 61 Shutter device 58, 62, 71, 81 Photoelectric sensor 64 Spacing expansion device 65A, 65B Expansion part 66 Roller 66a Rotating shaft 67 Arm 68 Connecting shaft 69 Bearing 70 Motor 75 Suction conveyance belt device 78 Belt rotating motor 79 Rotating shaft 80 Unit rotating motor

Claims (1)

A discharge device of a printing apparatus that discharges printed printing paper to a paper receiving unit on which printing paper is stacked,
A conveying device that conveys the printed printing paper by a conveying belt while sucking the printed paper, and guides the printed printing paper upward in the downstream direction in the conveying direction so that the printed printing paper has a downward posture;
Disposing a discharge device that drops the printed paper in a downward posture, which has been transported by the transport device, onto the paper receiver substantially above the paper receiver,
The discharging device is
A pair of suction conveyance belt devices arranged in parallel to the conveyance direction of the printed printing paper and conveying the printed printing paper that has been conveyed;
A rotation device that rotates the pair of suction conveyance belt devices such that the suction surfaces face each other in the conveyance direction;
The discharge device includes a detection device that detects the leading edge of the printed printing paper at a downstream portion, and when the leading edge of the printed printing paper is detected by the detection device, the pair of suction conveyance belt devices is detected by the rotating device. The paper discharge device of the printing apparatus is configured to rotate so that the suction surfaces face each other in the transport direction .

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