JP4449801B2 - Sheet feeding device - Google Patents

Description

  The present invention relates to a sheet feeding apparatus suitable for application to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine.

  In recent years, along with the diversification of recording media, in addition to sheets other than plain paper, such as thick paper, OHP paper, tracing paper, etc., whiteness and gloss have been added to the surface of the sheet in order to meet the market demand for colorization. Opportunities are increasing to form images on sheets such as coated paper and glossy paper that have been subjected to a coating process for printing. Of these, OHP paper, tracing paper, coated paper, and glossy paper have higher sheet surface smoothness than plain paper, so that when the sheets are stacked and stacked, they adhere to each other. Power is greater than plain paper.

  In general, in an image forming apparatus such as a copying machine or a printer, sheets stored in a tray are separated and conveyed one by one. However, when the adhesion between the sheets stacked on the tray increases, Separation deteriorates. As a result, when feeding (feeding) sheets from the tray, misfeeds such as double feeding in which a plurality of sheets are overlapped, and sheet conveyance delay are likely to occur. In particular, in an environment of high humidity, a greater adhesion force acts between the sheets, and therefore, it becomes a situation where double feed and misfeed are likely to occur.

  Therefore, conventionally, a technique has been proposed in which air is blown to the end portion of the sheet accommodated in the tray to float the sheet by flowing air between the sheets, thereby releasing the adhesion between the sheets (for example, , See Patent Documents 1 and 2). In addition, in order to enhance the separation effect (blowing effect) of the sheet by blowing air, a technique (for example, refer to Patent Documents 1 and 2) for moving the air blowing position by the air blowing means (up and down movement) There is also known a technique (for example, see Patent Documents 3 and 4) for moving (vertically moving) a sheet supporting unit that supports the mounted state. Furthermore, a member (see Patent Document 5) that regulates that a part of the sheets separated from each other by air blowing is lifted (see Patent Document 5), or a member that suppresses the floating amount of the sheet that floats by air blowing is provided. (See Patent Document 6) is also known.

JP-A-11-5543 Japanese Patent Laid-Open No. 2003-176051 JP-A-11-193138 JP 2001-106365 A JP 2002-104679 A JP 2003-63675 A

  However, the above conventional techniques have the following drawbacks. That is, in the case of moving the air blowing position, an air blocking means (flow path moving means) is provided between the air blowing means and the sheet, and this air blocking means is moved by a motor. It is necessary to provide a complicated and large driving mechanism in the vicinity of the stacked sheets and to secure a space for arranging the driving mechanism. This leads to an increase in size and cost of the apparatus.

  In addition, in the case of moving the sheet support means in order to enhance the sheet separation effect (spreading effect) by air blowing, it is necessary to arrange the uppermost sheet at a predetermined height when the sheet is supplied. It is necessary to perform the moving operation separately from the sheet feeding operation. Therefore, when supplying a plurality of sheets in order, an operation for moving the sheet support means (an operation for enhancing the separation effect of the sheets) and an operation for stopping the sheet support means (the uppermost sheet at a predetermined height). The operation for disposing them at the same time) is repeated in order at different timings, and productivity is lowered. Further, in order to increase the productivity, it is necessary to move the sheet support means at a high speed, so it is necessary to increase the driving force (power) and durability of the driving mechanism. As a result, the apparatus is increased in size and cost.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems. The object of the present invention is to blow air without moving the air blowing position in the sheet stacking direction or moving the sheet support means. An object of the present invention is to provide a sheet feeding device that can enhance the sheet separation effect.

The sheet supply apparatus according to the present invention includes a sheet storage unit that stores sheets in a stacked state, a sheet supply unit that sequentially supplies the sheets stored in the sheet storage unit, and an end of the sheet stored in the sheet storage unit An air blowing means for blowing air onto the part, a levitation height regulating member for regulating the levitation height of the sheet that is levitated by the air blowing by the air blowing means, and the levitation height regulating member that contacts the uppermost surface of the sheet The moving means for moving the contact portion in the sheet stacking direction, the acquisition means for acquiring information on the sheets stored in the sheet storage portion, and the movement range of the contact portion of the levitation height regulating member are acquired as described above. Control means for controlling based on the sheet information acquired by the means .

  In the sheet supply device according to the present invention, when air is blown to the end portion of the sheet accommodated in the sheet accommodating portion by the air blowing means, the upper layer sheet is floated by the flow of air between the sheets, and the floating sheet Will be in a state where the uppermost surface is in contact with the levitation height regulating member. In this state, when the contact portion of the floating height regulating member is moved in the sheet stacking direction by the moving means, the position of the floating sheet is also changed in the sheet stacking direction accordingly. Thereby, it becomes possible to change the blowing state of the air with respect to the sheet | seat of an upper layer part.

  According to the sheet supply device of the present invention, when the sheet is lifted by air blowing from the air blowing means, the contact portion of the floating height regulating member that contacts the top surface of the floating sheet is moved in the sheet stacking direction. By doing so, the position of the floating sheet can be changed in the sheet stacking direction with respect to the air blowing position. Thereby, even if the air blowing position or the sheet supporting means is not moved in the sheet stacking direction, the sheet separation effect by the air blowing can be enhanced.

  Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram showing a configuration example of an image forming apparatus to which the present invention is applied. The illustrated image forming apparatus 1 includes a receiving unit 5 connected to an image reading device 2 and an external device (such as a personal computer) 3 via a communication line 4, and an image writing unit based on image data received by the receiving unit 5. 6, an image recording control unit 7 that controls 6, a drum-shaped image carrier (photosensitive drum) 8 on which an electrostatic latent image is written by the image writing unit 6, and a circumferential direction of the image carrier 8. A charging device 9, a developing device 10, and a cleaner 11, a transfer roll 12 that transfers a toner image formed on the image carrier 8 to a sheet, a fixing device 13 that fixes the toner image transferred to the sheet, A discharge roll 14 that discharges the sheet on which the toner image is fixed by the fixing device 13, a discharge tray 15 that receives the sheet discharged by the discharge roll 14, and the image carrier 8 and the transfer roll 12. A sheet conveying section 16 that conveys the sheet toward the position (nip position), a plurality of sheet accommodating sections 17 that accommodate sheets used for image formation in a stacked state, and a sheet accommodated in the sheet accommodating section 17 The sheet supply unit 18 is configured to include an air blowing unit 19 that blows air onto the sheets stored in the sheet storage unit 17. Among these, the image reading apparatus 2 may exist as a functional unit of the image forming apparatus 1 or may exist as a functional unit separate from the image forming apparatus 1.

  The sheet supply apparatus according to the embodiment of the present invention is configured using a sheet storage unit 17, a sheet supply unit 18, and an air blowing unit 19. As shown in FIG. 2, the sheet storage unit 17 has a space that can store a predetermined number (a plurality of sheets) of stacked sheets (sheet bundle), and a bottom plate that supports the stacked sheets in a loaded state in this space. 17A. The bottom plate 17A is supported by an elevating mechanism (not shown) so as to be movable up and down. In the sheet accommodating portion 17, the sheet is supported in parallel with the main surface (upper surface) of the bottom plate 17A. Therefore, the sheet stacking direction (the direction of the arrow Z in FIG. 2) is a direction orthogonal to the main surface of the bottom plate 17A.

  The sheet supply unit 18 is disposed on the front side (the side on which the sheet is fed) of the sheet storage unit 17. As shown in FIGS. 2 and 3, the sheet supply unit 18 supplies the sheets 23 placed on the bottom plate 17 </ b> A of the sheet storage unit 17 in order from the uppermost sheet. The pickup roll 20, the feed roll 21 and a retard roll 22.

  The pick-up roll 20 descends when the sheets 23 accommodated in the sheet accommodating portion 17 are sequentially supplied, contacts the uppermost surface of the sheet with a predetermined pressing force, and rotates in the direction of the arrow in the drawing. Thus, the sheet 23 is called from the sheet storage unit 17. The uppermost surface of the sheet refers to the upper surface of the sheet (top sheet) disposed at the uppermost position in the sheet stacking direction among the sheets stored in the sheet storage unit 17. The feed roll 21 rotates in the direction of the arrow in the drawing to feed the sheet 23 called by the pickup roll 20 toward the sheet conveying unit 16 while niping with the retard roll 22. The retard roll 21 comes into contact with the lower surface side of the sheet 23 called between the feed roll 21 (nip position) by the pickup roll 20 and an appropriate frictional resistance force (braking force) is applied to the lower surface sheet in this contact state. Is used to prevent double feeding of sheets.

  The air blowing unit 19 is configured by using a blower such as a blower or a fan, for example, and is disposed on one side of the sheet storage unit 17. The air blowing unit 19 blows air from the direction perpendicular to the sheet supply direction to the side end portion of the sheet 23 accommodated in the sheet accommodating portion 17 to lift the sheet 23 in the upper layer portion by blowing air, and the sheets And the adhesion between the sheets is released. The side end portion of the sheet refers to an end portion of the sheet that is disposed in the sheet storage portion 17 so as to face in a direction orthogonal to the sheet supply direction (the direction of the arrow Y in FIGS. 2 and 3). The sheet supply direction is a direction in which the sheet moves when the sheet is supplied by the sheet supply unit 18 in the sheet storage unit 17.

  The air blowing unit 19 integrally has a nozzle 19A that forms an air blowing port. A nozzle (air outlet) 19 </ b> A of the air blowing unit 19 is connected to the side wall portion of the sheet storage portion 17 in a state of being close to and facing the side end portion of the sheet 23 stored in the sheet storage portion 17 in a stacked state. Yes. Further, the opening size and attachment position of the nozzle 19A in the sheet stacking direction are set under the condition that air is blown onto at least the upper layer portion of the stacked sheet supported by the bottom plate 17A.

  Above the bottom plate 17A, a plurality of (two in the illustrated example) levitation height regulating members 24 are provided at a predetermined distance in the sheet stacking direction. The levitation height regulating member 24 regulates the levitation height of the sheet by coming into contact with the uppermost surface of the sheet that is levitated by the air blowing from the air blowing unit 19. Each levitation height regulating member 24 is formed, for example, of a resin in a flat plate shape, and is disposed in the vicinity of the nozzle 19 </ b> A on the same side as the air blowing unit 19 in a direction orthogonal to the sheet supply direction. The levitation height regulating members 24 are arranged at the same position at a position slightly higher than the nozzle 19A in the sheet stacking direction, and are arranged on both sides of the nozzle 19A so as to sandwich the nozzle 19A in the sheet feeding direction. ing.

  The levitation height regulating member 24 is supported by the rotating shaft 25 as shown in FIG. The rotation shaft 25 is stretched along the side wall of the sheet storage portion 17 in parallel with the sheet supply direction. In the axial direction of the rotary shaft 25, the levitation height regulating members 24 are attached at a predetermined interval. In addition, the base end portion of each levitation height regulating member 24 is fixed to the rotary shaft 25 by using a fixing means such as a screw, an adhesive, or press-fitting.

  A rotating gear 27 that rotates using a motor 26 as a drive source is attached to the rotating shaft 25. The rotating shaft 25 rotates together with the rotating gear 27. The rotation gear 27 meshes with the idle gear 28, and the idle gear 28 meshes with the drive gear 29. The drive gear 29 is attached to the output shaft of the motor 26, and rotates integrally with the output shaft when the motor 26 is rotationally driven. These rotating shaft 25, motor 26, rotating gear 27, idle gear 28, drive gear 29, and the like constitute moving means.

  In this configuration, when the motor 26 is rotationally driven, the driving force is transmitted to the rotary gear 27 via the drive gear 29 and the idle gear 28. Thereby, the rotating shaft 25 rotates integrally with the rotating gear 27, and the free end side of the levitation height regulating member 24 moves in the direction of the arrow about the rotating shaft 25 according to the rotating direction. Therefore, from the state where the levitation height regulating member 24 is horizontally supported as shown in FIG. 4, the rotating shaft 25 is rotated clockwise by a predetermined angle (about 20 ° in the example) as shown in FIG. Accordingly, the position of the free end of the levitation height regulating member 24 moves downward accordingly. Further, as shown in FIG. 5, from the state in which the levitation height regulating member 24 is tilted and supported, the rotary shaft 25 is rotated in the counterclockwise direction (direction opposite to the previous direction) with the same rotation angle (about 20 °) as before. Accordingly, the position of the free end of the levitation height restricting member 24 moves upward and returns to the state shown in FIG.

  Here, when air is blown from the air blowing unit 19, if the air flow area in the sheet stacking direction is defined by the opening end position of the nozzle 19A, the upper boundary of the air flow area is the upper boundary of the nozzle 19A. It is defined by the opening end position, and the lower boundary of the air flow area is defined by the lower opening end position of the nozzle 19A. With respect to the air flow region thus defined, the swing range of the levitation height regulating member 24 is such that the free end of the levitation height regulating member 24 is above the upper boundary of the air flow region as shown in FIG. The range from the retracted position to the position where the free end of the levitation height regulating member 24 crosses the upper boundary of the air flow area and enters the air flow area as shown in FIG. 5 is set. Thereby, when the levitation height regulating member 24 is swung, at least a part of the uppermost sheet crosses the air flow path.

  In the sheet supply apparatus having the above-described configuration, when a plurality of sheets 23 placed on the bottom plate 17A in the sheet storage unit 17 are sequentially supplied by the sheet supply unit 18, the nozzle 19A of the air blowing unit 19 is prior to that. Then, air is blown toward the side end portion of the seat 23, and the levitation height regulating member 24 is swung around the rotation shaft 25 by the rotational drive of the motor 26. Incidentally, the air blowing operation by the air blowing unit 19 and the swinging operation of the flying height regulating member 24 by the motor 26 are continuously performed until the sheet feeding operation by the sheet feeding unit 18 is completed.

  Thereby, air is blown from the direction orthogonal to the sheet supply direction to the side end portion of the sheet 23 placed on the bottom plate 17A. When air flows between the sheets by this air blowing, the adhesion between the sheets is released there. Further, levitation force acts on the upper layer sheet 23 due to the flow of air between the sheets, and the upper layer sheet 23 is lifted by receiving this levitation force. At this time, the uppermost surface of the floated sheet (top sheet) 23 comes into contact with each of the float height regulating members 24 (see FIG. 2). As a result, the floating height of the sheet (the upper limit position of the sheet when the sheet is lifted) is regulated by the floating height regulating member 24 as shown in FIG.

  In this state, when the rotary shaft 25 is rotated clockwise by the rotational drive of the motor 26, the position of the free end of the levitation height regulating member 24 (the portion in contact with the uppermost surface of the seat) moves downward. Accordingly, the position of the levitation sheet also moves downward. Further, when the rotary shaft 25 is rotated counterclockwise by the rotational drive of the motor 26 from this state, the position of the free end of the levitation height regulating member 24 moves upward, and accordingly the position of the levitation sheet is also changed. Move upward. As a result, the position of the sheet 23 in the lifted state fluctuates (moves up and down) in the sheet stacking direction with respect to the air blowing position (air flow area) by the air blowing unit 19. Therefore, even if the nozzle 19A of the air blowing unit 19 is moved up and down and the bottom plate 17A is not moved up and down, the state of air blowing on the upper sheet 23 can be changed.

  Further, since the sheet 23 floated by blowing air can be forcibly pushed down by the floating height regulating member 24, the floated sheet can be quickly raised and lowered in the sheet stacking direction. Furthermore, the speed at which the levitation sheet is raised and lowered can be arbitrarily controlled (variable) by the rotation speed (rotation speed) of the motor 26. Further, independent of the operation of the sheet supply unit 18, the floating height regulating member 24 can be swung. Further, the position of the floating sheet can be repeatedly varied in the sheet stacking direction by repeatedly swinging the free end of the floating height regulating member 24 in the sheet stacking direction by rotating the motor 26. Further, the position of the floating sheet can be periodically changed in the sheet stacking direction by periodically swinging the free end of the floating height regulating member 24 in the sheet stacking direction by the rotation drive of the motor 26.

  Further, the swinging movement of the levitation height regulating member 24 around the rotation shaft 25 causes the free end (abutting portion) of the levitation height regulating member 24 that abuts on the uppermost surface of the seat to be the upper boundary of the air flow area. Since it is configured to reciprocate so as to cross, even if several sheets 23 are lifted to the outside of the air flow area while being in close contact with each other, they are pushed down by the floating height regulating member 24 so as to be within the air flow area. Can be returned to. Thereby, the separation effect of the sheet | seat by air spraying can be acquired again. Further, by repeating the swinging operation of the levitation height regulating member 24, it is possible to repeatedly obtain the sheet separation effect by blowing air. Furthermore, when the sheet 23 in a floating state crosses the upper boundary of the air flow area downward, air is blown at the moment when the sheet 23 enters the air flow area, and air is blown in order from the lower sheet. Therefore, the sheet can be more reliably separated as compared with the case where the free end of the levitation height regulating member 24 is moved only within the air flow region.

  Further, if a motor (drive source) 26 for swinging the levitation height regulating member 24 is a pulse motor or servo motor that can easily control the rotation direction and the rotation amount, a motor that drives the motor 26 is used. Using the driver, it is possible to arbitrarily change the moving range when moving the free end of the flying height regulating member 24 in the sheet stacking direction, together with the swinging range of the flying height regulating member 24. As a result, the swing range of the levitation height regulating member 24 is narrowed, and the free end of the levitation height regulating member 24 is moved vertically (smallly) in the sheet stacking direction, or the levitation height regulating member 24 is oscillated. The range can be widened and the free end of the levitation height regulating member 24 can be moved up and down greatly in the sheet stacking direction.

  Further, if information on the sheets stored in the sheet storage unit 17 (for example, sheet type, basis weight, size, etc.) is designated on the operation panel, the information on the designated sheets is obtained by an acquisition means (not shown). If the configuration in which the motor driver acquires and controls the operating range of the flying height regulating member 24 (the movement range of the free end of the flying height regulating member 24) based on the obtained sheet information is actually used The swing range of the flying height regulating member 24 can be appropriately controlled in accordance with the characteristics of the supplied sheet. Thereby, since the free end of the levitation height regulating member 24 can be moved up and down within the optimum range, the sheet separation effect can be further enhanced. Further, when acquiring the information on the sheets stored in the sheet storage unit 17, the sheet information is detected by a detecting unit such as a sensor, and the detected sheet information is acquired by the acquiring unit. It is also possible.

  FIG. 6 is a diagram showing another embodiment of the present invention. In this embodiment, the base end portion of the levitation height regulating member 24 is supported on the rotary shaft 25 in a rotation free state. Accordingly, the levitation height regulating member 24 can be freely swung around the rotation shaft 25 while the rotation shaft 25 is fixed (rotation stopped). A movement operation member 30 is provided on the rotation shaft 25. The moving operation member 30 is fixedly attached to the rotating shaft 25 or the rotating gear 27, and rotates integrally with the rotating shaft 25 and the rotating gear 27 when the motor 26 is driven to rotate.

  On the other hand, a biasing member 31 made of a spring member such as a compression spring is attached to the levitation height regulating member 24. One end of the urging member 31 is fixed to the levitation height regulating member 24, and the other end is fixed to the apparatus frame portion 32. As described above, the urging member 31 is in the clockwise direction around the rotation shaft 25 (the free end of the levitation height restriction member 24) with respect to the levitation height restriction member 24 supported rotatably on the rotation shaft 25 as described above. The urging force in the direction of moving downward) is applied. On the other hand, the moving operation member 30 has a structure in which a part of the disk is cut out, and one end surface of the cut-out portion is brought into contact with the lower surface of the levitation height regulating member 24, whereby the levitation height regulating member. In addition to restricting (blocking) the clockwise swing motion of 24 and rotating counterclockwise around the rotating shaft 25, the levitation height restricting member 24 resists the biasing force of the biasing member 31. Are moved in the same direction to move the free end of the levitation height regulating member 24 upward.

  In such a configuration, in a state where the levitation height regulating member 24 is held in a substantially horizontal position (the state shown in FIG. 6), one end surface of the moving operation member 30 abuts on the lower surface of the levitation height regulating member 24, and The urging force of the urging member 31 acts on the contact portion. When the rotary shaft 25 and the moving operation member 30 are rotated in the clockwise direction integrally with the rotary gear 27 by the rotational drive of the motor 26 in this state, the levitation height regulating member 24 receives the urging force of the urging member 31. It swings in the clockwise direction together with the moving operation member 30. Then, as shown in FIG. 7, the moving operation member 30 is further rotated in the clockwise direction in a state where the free end of the levitation height regulating member 24 is in contact with the uppermost surface of the seat 23 with the urging force of the urging means 31. Then, the floated sheet is pushed down to the position of the stacking state before it floats, and the one end surface of the moving operation member 30 is separated from the bottom surface of the float height regulating member 24.

  Thereafter, when the rotary shaft 25 and the moving operation member 30 are rotated counterclockwise together with the rotating gear 27 by the rotational drive of the motor 26, one end surface of the moving operation member 30 is again restricted to the floating height during the rotation. When the movement operation member 30 is rotated in the same direction against the urging force of the urging member 31 from that state, the movement operation member 30 is pushed up and the flying height is increased. Since the regulating member 24 swings counterclockwise, the levitation height regulating member 24 gradually approaches the horizontal state (original state).

  When the levitation height regulating member 24 is swung according to such an operation, the urging force of the urging member 30 applied to the levitation height regulating member 24 is used to move the free end of the levitation height regulating member 24. Since the sheet can be moved downward, even if the free end of the levitation height regulating member 24 hits the uppermost surface of the sheet 23 when the sheet is in the stacked state, the sheet 23 is not damaged. Therefore, a wide swing range (operation range) of the levitation height regulating member 24 can be secured. Further, the sheet 23 floated by blowing air can be sufficiently pushed down to the original position again by the floating height regulating member 24. Therefore, air can be blown and floated in order from the uppermost sheet 23 again. Moreover, such an operation can be repeated many times.

  In the above embodiment, the air blowing unit 19 is provided on one side portion of the sheet accommodating portion 17 and air is blown to the side end portion of the sheet 23 by the air blowing unit 19. For example, as shown in FIG. 8, an air blowing unit 19 is provided at the front portion of the sheet storage portion 17, and the front end portion of the sheet 23 (the sheet disposed facing the downstream side in the sheet supply direction) is provided by the air blowing unit 19. The same applies to the case where air is blown to the end of the sheet, or the air is blown to the rear end of the sheet (the end of the sheet arranged facing the upstream side in the sheet feeding direction) although not shown. Is possible.

  In addition, the levitation height regulating member has an elliptical outer peripheral shape, and the uppermost surface of the levitation sheet is in contact with the lower end of the outer circumferential surface of the levitation height regulating member, and the levitation height regulating member itself rotates. By doing so, it is possible to adopt a configuration in which the contact portion with the sheet moves (moves up and down) in the sheet stacking direction.

1 is a schematic diagram illustrating a configuration example of an image forming apparatus to which the present invention is applied. It is a side view showing an example of composition of a sheet supply device concerning an embodiment of the present invention. It is a top view which shows the structural example of the sheet supply apparatus which concerns on embodiment of this invention. It is FIG. (1) which shows the operation mechanism of the levitation height control member which concerns on embodiment of this invention. It is FIG. (2) which shows the operation mechanism of the levitation height control member which concerns on embodiment of this invention. It is FIG. (The 1) which shows the operation | movement mechanism of the levitation height control member which concerns on other embodiment of this invention. It is FIG. (2) which shows the operation | movement mechanism of the levitation height control member which concerns on other embodiment of this invention. It is a figure which shows the other example of application of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 17 ... Sheet accommodating part, 18 ... Sheet supply unit, 19 ... Air spraying unit, 23 ... Sheet, 24 ... Levitation height regulating member, 25 ... Rotating shaft, 26 ... Motor, 27 ... Rotating gear, 28 ... Idle gear, 29 ... Drive gear, 30 ... Moving operation member, 31 ... Biasing member

Claims (1)

A sheet storage section for storing sheets in a stacked state;
Sheet supply means for sequentially supplying the sheets stored in the sheet storage section;
Air blowing means for blowing air to the end of the sheet accommodated in the sheet accommodating portion;
A levitation height regulating member that regulates the levitation height of the sheet that is levitated by the air blowing by the air blowing means;
Moving means for moving a contact portion of the levitation height regulating member that contacts the uppermost surface of the sheet in a sheet stacking direction;
Obtaining means for obtaining information of the sheets accommodated in the sheet accommodating portion;
A sheet supply apparatus comprising: a control unit that controls a movement range of the contact portion of the levitation height regulating member based on sheet information acquired by the acquisition unit.

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