JP5053698B2 - Paper receiving device - Google Patents

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper receiving device provided in an image forming apparatus such as a printing machine and a copying machine, and to a paper receiving device that sequentially stacks papers that are formed and discharged by an image forming unit on a paper receiving table. .

  Conventionally, a water-in-oil type emulsion ink containing an oil component has been mainly used as an ink for an image forming apparatus, for example, a stencil printing machine, but nowadays, an oil component is used instead of the water-in oil type ink. Has been proposed to use water-based inks having 0 or substantially 0 (for example, Patent Document 1). That is, by making the oil component substantially zero, the generation of odor is suppressed, the influence on the environment is reduced, and the drying efficiency is improved.

  However, when water-based ink is used, the above-described advantages can be obtained, but after printing, ink moisture rapidly infiltrates from the surface of the paper, so that a paper entrainment phenomenon, that is, a curling phenomenon occurs rapidly.

  FIG. 5 specifically shows the process of the curl phenomenon. The printing paper P is in a flat state as shown in the uppermost stage (A1) during printing, but after printing, the printing surface Pa of the printing paper P is As shown in the second step (A2), the left and right ends are curled back to the opposite side to the printing surface (upper surface) Pa side as shown in the second step (A2), and further, as shown in the third step (A3). The entire paper P is deformed into an inverted U shape that is convex toward the printing surface Pa side. As shown in FIG. 5, the printing paper P whose left and right ends curl is mainly paper whose paper fibers extend in the front-rear direction (for example, the transport direction), and the paper fibers are in the left-right direction (a direction orthogonal to the transport direction). ), The front and rear end portions are mainly curled after printing. Incidentally, the reverse U-shaped change of the printing paper P shown in (A1) to (A3) of FIG. 5 appears remarkably in a short time on a paper whose upper surface is lacquered. Deforms in seconds to seconds.

  Second stage (A2) or third stage (A3) in FIG. 5 When the printing paper P is discharged onto the paper tray in such a deformed state or in the middle of the deformation, as shown in FIG. When the printing paper P is stacked by this method, the printing paper P is stacked with the left and right ends of the printing paper P being wound inside, so that the alignment of the printing paper P is deteriorated and the quality of the printing paper P is deteriorated. Of course, it becomes difficult to keep the height of the loading surface of the printing paper P constant.

  Further, in the structure in which the paper is stacked on the paper tray 100 with little time after printing, since the ink is not sufficiently dried, the ink print-through occurs on the adjacent print paper P when the paper is stacked, and the paper Often dirty.

  In order to prevent the curling and promote the drying, several devices for preventing the curling have been developed. As one of them (Patent Document 2), an air blowing device that is disposed near the leading edge of the paper above the paper cradle (pile) and blows air in parallel with the paper, and above the paper cradle and the carry-out device 2. Description of the Related Art There is a curl prevention device that includes a fan or the like that is disposed above and sends air substantially vertically downward. According to this curl prevention device, it is possible to prevent the paper from curling by pressing the paper with air blown from an air blower or a fan. Moreover, drying can be accelerated | stimulated with blowing air.

JP 2005-272513 A JP 58-31831 A

  As in the conventional paper receiving device (Patent Document 2), the structure in which air is simply blown onto the printing paper discharged from the paper discharging device can suppress the curling of the printing paper. Since printing sheets are stacked in a short time, the drying time cannot be sufficiently obtained, and the effect of preventing ink show-through on adjacent sheets during loading is small.

  The inventor of the present application relates to the characteristics of the printing paper, and after several tens of seconds after the printing paper P curls in an inverted U shape as shown in the third stage (A3) in FIG. As shown in A4), attention is paid to the fact that the left and right edges of the printing paper curl upward so as to return to the flat state, and this characteristic is used to prevent the occurrence of curling immediately after printing and to dry the ink. It is an object of the present invention to provide a paper receiving apparatus that can sufficiently ensure the above.

In order to solve the above-mentioned problem, the invention according to claim 1 of the present application is a paper receiving device for placing the paper on which the image is formed by the image forming unit on the paper receiving base 31 in a stacked state. An intermediate stack device 40 that temporarily holds the paper on which the image has been formed by the image forming unit and discharges the paper onto a paper tray after a predetermined time has elapsed is disposed at an upper position. A pair of support legs 42 erected at intervals in the paper width direction, a pair of holding plates 41 supported by both support legs 42 via a rotation shaft 45, and both holding plates 41, and a drive actuator 46 for driving between a substantially horizontal holding position and a discharge position depending downward, and further, above the intermediate stack apparatus 40, the sheet of paper on the intermediate stack apparatus 40 Check to four corners S1, from above, respectively It is arranged a blower mechanism 50 for blowing.

  According to the above configuration, the image-formed paper discharged from the image forming unit is temporarily held by the intermediate stack device, and the flat state is forcibly maintained by the air blowing mechanism for a predetermined time. As shown in the fourth stage (A4) in FIG. 5, it is possible to gain time for returning to a flat shape due to the characteristics of the paper itself, and it is possible to discharge the paper that has returned to a flat shape in a natural state to a paper receiving tray. As a result, the sheets can be neatly stacked on the paper tray.

  Further, since the air is blown by the air blowing mechanism while being held by the intermediate stack device, the ink on the paper can be quickly dried, thereby preventing the show-through of the printing paper when stacked.

Further, it is possible to efficiently and surely maintain the sheet on the intermediate stack and to dry it. In particular, the paper curl phenomenon starts to occur at the four corners, so that by blowing air intensively on the four corners of the paper, the air blowing mechanism can be downsized compared to the case of blowing air over the entire paper, The paper can be maintained in a flat shape efficiently. Incidentally, even if the central portion is not sufficiently dried, the paper can be sufficiently maintained flat by blowing air intensively to the four corner portions.

The invention according to claim 2 is a method invention, comprising an intermediate stack device 40 at a position above the paper cradle 31 and a blower mechanism 50 above the intermediate stack device 40, wherein the intermediate stack device 40 is provided. Includes a pair of support legs 42 erected at intervals in the paper width direction, a pair of holding plates 41 rotatably supported on both support legs 42 via a rotation shaft 45, In a paper discharge method of a paper receiving apparatus having a drive actuator 46 that drives a holding plate 41 between a substantially horizontal holding position and a discharge position that hangs downward, an image is formed by an image forming unit. The intermediate stack device 40 temporarily holds the sheet by the pair of holding plates 41 at the holding position, while the blower mechanism 50 is respectively placed on the four corner portions S1 of the held sheet from above. Air is blown, and after a predetermined time, The pair of holding plates 41 are opened to the discharge position by the drive actuator 46, and the paper is placed on the paper tray 31 while guiding the edges of the paper by the hanging holding plate 41 and the pair of support legs 42. To release.

  According to the said structure, the effect similar to the case of the said Claim 1 is acquired.

[Embodiment of the Invention]
1 to 4 show an example in which a paper receiving apparatus according to the present invention is provided in a stencil printing machine, and a first embodiment of the present invention will be described based on these drawings.

(Overview of printing press)
FIG. 1 is a schematic side view of a stencil printing machine equipped with a paper receiving apparatus according to the present invention. For convenience of explanation, the paper supply side (left side of the drawing) is referred to as “rear”, and the paper transport side, that is, the paper discharge side ( The right side of the drawing will be referred to as “front” and will be described below. In FIG. 1, a printing machine main body 1 is provided with a paper feeding device 2 at the rear end, a paper receiving device 3 at the front end, and an image reading device 4 at the upper side.

  In the printing machine main body 1, a printing unit 5 is provided as an image forming unit at an approximately middle part in the front-rear direction. A plate-making device 6 is provided above the printing unit 5. A plate discharging device 7 is provided, and a paper discharge device 8 is provided between the printing unit 5 and the paper receiving device 3. A pair of timing rollers 18 is provided between the printing unit 5 and the paper feeding device 2.

  The printing unit 5 includes a printing plate cylinder 11 in which an ink supply roller 10 is inscribed and rotationally driven in the direction of an arrow R, and a vertically movable pressing roller 12 that faces the printing plate cylinder 11 so as to come into contact with the printing plate cylinder 11 from below. And printing is performed on the upper surface of the printing paper P between the printing plate cylinder 11 and the pressing roller 12. As the ink to be used, an aqueous ink having an oil component of 0 or substantially 0 is mainly used, but a conventional water-in oil type ink can also be used.

  The plate making apparatus 6 includes a master roll 13, a thermal head 14 for making a stencil sheet N supplied from the master roll 13, a platen roller 15, and the like, and the stencil sheet N from the master roll 13 is transferred to the thermal head 14. The plate is made by the method described above, cut into predetermined dimensions, and then supplied to the surface of the printing plate cylinder 11.

  The plate discharging device 7 includes a drawing roller 16 and a take-up roller 17. The used stencil sheet N mounted on the printing plate cylinder 11 is removed and drawn into the plate discharging device by the drawing roller 16. Wind up with.

  The sheet feeding device 2 includes a sheet feeding table 23, and includes a sheet feeding roller 19 and a separating plate 20 at a front end portion of the sheet feeding table 23, and the printing sheets P stacked on the sheet feeding table 23. Are supplied to the timing roller 18 one by one from the top.

  The pair of upper and lower timing rollers 18 and 18 are rotated at an appropriate timing in synchronization with the drive of the printing plate cylinder 11 and feed the printing paper P into the printing unit 5.

  The paper discharge device 8 includes a plurality of paper discharge belts 21, a suction box 22, and a suction fan 23, and the suction box 22 is connected to the suction fan 23. A flat guide plate 24 is erected. Due to the air suction action of the suction box 22, the paper P on the paper discharge belt 21 is attracted to the paper discharge belt 21 and discharged to the paper receiving device 3.

(Detailed structure of the paper receiving device 3)
In FIG. 1, the paper receiving device 3 includes a paper receiving base 31 supported on the front end surface 1 a of the printing press main body 1 in a substantially horizontal state or a front downward inclined state, and an intermediate disposed in the upper direction of the paper receiving base 31. The stacking device 40 includes four air blowing mechanisms 50 arranged above the intermediate stacking device 40. On the upper surface of the paper receiving tray 31, a stopper plate 35 is disposed at the front end portion, and side guide rods (or guide plates) 34 are disposed at the left and right side portions.

  FIG. 3 is an enlarged sectional view taken along the line III-III of the paper receiving device 3 of FIG. 1, and the intermediate stacking device 40 includes a pair of left and right holding plates 41 arranged at intervals in the left and right directions. The plates 41 are respectively fixed to rotating shafts 45 arranged in parallel (substantially horizontal) to the paper transport direction F, and the rotating shafts 45 are support legs 42 erected on both left and right ends of the paper receiving base 31. The bearing unit 43 is rotatably supported and is connected to a drive actuator (for example, a stepping motor) 46. By rotating the rotating shaft 45 by the drive actuator 46, each holding plate 41 hangs down substantially horizontally as shown in FIG. 3 and in a downward position as shown in FIG. It rotates between the discharge position (open position).

  FIG. 2 is a plan view of the intermediate stacking device 40, and the drive actuator 46 of each rotating shaft 45 is electrically connected to the control unit 52, and the control unit 52 allows the printing paper from the paper discharge device 8 to be printed. It is controlled to open and close at predetermined time intervals in accordance with the discharge speed. As an example, after the sheet is discharged onto the intermediate stack device 40, the holding plate 41 is controlled to open downward temporarily after 10 seconds to several tens of seconds have elapsed. As shown in FIG. 1, an optical sensor 55 that detects the passage of the printing paper P is disposed between the paper discharge device 8 and the intermediate stacking device 40, and the passage of the printing paper P is detected by the optical sensor 55. It is also possible to control the holding plate 41 to open after a predetermined time has elapsed after detection.

The four air blowing mechanisms 50 are arranged on the holding plate 41 so as to blow air from above to the four corner portions S1 of the printing paper P.

(Function)
Since the operation of the entire stencil printing machine has already been described in the description of each device, the printing paper P is discharged from the printing unit 5 in FIG. The operation up to this point will be described.

(1) In FIG. 1, an image is printed on the upper surface of the printing paper P in the printing unit 5, and the printed printing paper P is discharged onto the paper discharge belt 21 of the paper discharge device 8.

(2) In the paper discharge device 8, the printing paper P is conveyed forward while being attracted to the upper surface of the paper discharge belt 21 by the suction box 22, so that the printing paper P can be conveyed in a substantially flat state. it can. That is, depending on the characteristics of the ink and the paper, the left and right ends of the paper P begin to warp immediately after printing, but on the paper discharge belt 21, the print paper P is attracted to the upper surface of the paper discharge belt 21 by the suction action of the suction box 22. Therefore, the sheet can be conveyed forward while preventing the sheet from curling. Further, the left and right guide plates 24 can prevent the printing paper from shifting to the left and right.

(3) Next, the paper is discharged from the front end portion of the paper discharge belt 21 onto the holding plate 41 of the intermediate stack device 41, and the front end of the printing paper P abuts against the stopper plate 35. In the state shown in FIG. And held on the holding plate 41. While being held on the holding plate 41, the air from the blower mechanism 50 is blown onto the four corner portions S1 of the printing paper P from above, whereby the four corner portions S1 of the printing paper P are warped downward. Prevent, keep the printing paper P flat, and quickly dry the ink.

(4) When a predetermined time (10 seconds to several tens of seconds) elapses with the printing paper P being held as shown in FIG. 3, both holding plates 41 are opened downward as shown in FIG. The printing paper P is naturally dropped on the upper end surface of the stacked paper P. As shown in FIG. 1, when the optical sensor 55 is disposed between the paper discharge device 8 and the intermediate stack device 40, both holding plates 41 are detected after a predetermined time has elapsed after detection by the optical sensor 55. Opens.

  As described above, since the printing paper P is kept flat on the holding plate 41 for a predetermined time and dried, as described in the fourth stage (A4) of FIG. The printing paper returns to the flat state. Therefore, uneven paper stacking due to the curl phenomenon can be avoided, and the print paper show-through phenomenon can also be avoided. In particular, in the configuration in which the four corner portions S1 of the printing paper P are intensively dried, even if the central portion of the printing paper is insufficiently dried, the four corner portions that tend to warp are dried. Thus, the plane state of the printing paper can be maintained efficiently by drying in a short time.

[Other embodiments]
(1) In the above embodiment, only the stepping motor is used as the drive actuator 46 of the intermediate stack device 40. However, the drive mechanism of the intermediate stack in the present invention is not limited to the stepping motor, and is a cylinder device or a link. A mechanism or the like can also be used. Also, a drive motor or the like and a trigger device can be combined. For example, the holding plate 41 is locked in the horizontal holding state by the latch of the trigger device, and the holding plate 41 is opened downward by its own weight by removing the latch, and then returned to the original holding state by the drive motor. It is also possible to configure.

(2) It is possible to adopt a structure in which air having a high temperature (70 ° to 80 °) is blown from the blower mechanism 50 to the paper. In this case, drying of the ink on the paper is further promoted.

(3) The present invention is not limited to a paper receiving device of a stencil printing machine, and instead of a printing unit including a printing drum or the like as an image forming unit, a paper receiving device of an ink jet printing machine provided with an ink jet nozzle head, It can also be applied to copying machines and the like.

(5) The paper discharge speed by the paper discharge device 8 shown in FIG. 1 can be changed according to the size of the paper, the type of printing, and the like.

1 is a schematic side view of a stencil printing machine provided with a paper receiving apparatus according to a first embodiment of the present invention. FIG. 2 is an enlarged plan view of the paper receiving device in FIG. 1. FIG. 3 is an enlarged cross-sectional view taken along the line III-III of the paper receiving device of FIG. 1. FIG. 3 is an III-III cross-sectional enlarged view of the paper receiving device of FIG. 1 showing a state when printing paper is discharged. It is sectional drawing which shows the process of the curl phenomenon of the paper after printing. It is sectional drawing which shows the state with which the paper curled on the paper receiving stand was loaded.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer main body 3 Paper receiving device 5 Printing unit (an example of an image formation part)
DESCRIPTION OF SYMBOLS 8 Paper discharge apparatus 21 Paper discharge belt 22 Suction box 24 Side guide plate 31 Paper receiving stand 31 Paper receiving stand 40 Intermediate stack apparatus 41 Holding plate 46 Drive motor 50 Blower mechanism 52 Control part

Claims (2)

In the paper receiving apparatus for placing the paper on which the image is formed in the image forming unit on the paper receiving tray (31) in a stacked state,
An intermediate stack device (40) is disposed above the paper cradle (31) to temporarily hold the paper on which the image has been formed by the image forming unit and discharge it onto the paper cradle after a predetermined time has elapsed. And
The intermediate stacking device (40) has a pair of support legs (42) erected at intervals in the paper width direction, and both support legs (42) are rotatable via a rotation shaft (45). A pair of holding plates (41) supported by each other, and a drive actuator (46) for driving both holding plates (41) between a substantially horizontal holding position and a release position depending downward. And
Furthermore, a blowing mechanism (50) for blowing air from above each of the four corner portions (S1) of the paper on the intermediate stack device is arranged above the intermediate stack device (40). Paper receiving device. An intermediate stack device (40) is provided at an upper position of the paper tray (31), and an air blowing mechanism (50) is provided at an upper position of the intermediate stack device (40). A pair of support legs (42) erected at an interval from each other, and a pair of holding plates (41) supported rotatably on both support legs (42) via a rotation shaft (45) And a drive actuator (46) for driving both holding plates (41) between a substantially horizontal holding position and a discharge position depending downward, in a paper discharge method for a paper receiving apparatus,
The intermediate stack device (40) temporarily holds the paper on which the image is formed by the image forming unit by the pair of holding plates (41) at the holding position, while the blower mechanism (50) the four corners of the sheet of the holding state (S1), and blowing air from above each
After a predetermined time has elapsed, the pair of holding plates (41) are opened to the discharge position by the drive actuator (46), and the edge of the sheet is moved by the hanging holding plates (41) and the pair of support legs (42). A paper discharge method of a paper receiving device that discharges paper onto the paper receiving tray (31) while guiding.

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