JP5528192B2 - Sheet stacking device and printer - Google Patents

Description

  The present invention relates to a sheet stacking apparatus and a printer including the same.

  2. Description of the Related Art Conventionally, a sheet stacking apparatus such as a printer including a plurality of trays for stacking printed sheets can set a larger number of sheet discharge destinations as the number of trays increases. However, if the number of trays is increased without changing the size of the printer, the interval between the individual trays is reduced. In general, since a plurality of trays are provided so as to overlap each other, if the interval between the trays becomes narrow, it becomes difficult to take out the sheets stored in these trays. In view of this, a printer has been proposed in which each tray can be pulled out and the tray is pulled out when the sheet is taken out.

  However, if the trays of the printer can be pulled out in this way, the trays may be accidentally pulled out during the sheet stacking operation. In this case, there is no member that stably receives the sheets discharged by the stacking operation, so that a jam (paper jam) occurs or each mechanism portion of the tray is damaged due to the jam. Occurs.

  Japanese Patent Application Laid-Open No. 2004-228688 proposes a configuration that allows the tray to be pulled out or returned to the original position even when the sheet discharging apparatus is performing a sheet discharging operation. According to this configuration, when a sheet is discharged while the upper tray is pulled out, the sheet is stacked across the bottom plate of the upper tray and the bottom plate of the under tray. Since the sheet is scooped by the bottom plate of the upper tray when the upper tray is pushed back, the sheet can be continuously stored.

JP 08-157127 A

  In the configuration described in Patent Document 1, when the pulled-out upper tray is pushed back, sheets stacked across the bottom plate of the upper tray and the bottom plate of the under tray are moved to the rear end wall of the under tray. Then, after the sheet comes into contact with the rear end wall of the under tray and cannot move, the sheet is scooped up on the bottom plate of the upper tray. Therefore, while the sheet moves until it abuts against the rear end wall of the under tray, or when it abuts against the rear end wall, the sheet bends to cause jamming, or the sheet is rubbed to cause scratches on the printing surface. There is a risk of

  Therefore, an object of the present invention is to allow the tray to be pulled out and returned to the original position during the sheet discharging operation, and to prevent the occurrence of problems such as jams and scratches on the sheet as the tray moves. An object of the present invention is to provide a sheet stacking apparatus and a printer including the same.

  A sheet stacking apparatus according to the present invention includes a sheet discharge unit that discharges a sheet, a sheet stacking movable unit that has a stacking surface on which the sheet discharged by the sheet discharge unit is stacked, and a sheet stacking unit that is positioned below the sheet stacking movable unit and can be pulled out. A movable tray; and an interlocking mechanism that engages the movable tray and the sheet stacking movable means. The interlocking mechanism transmits the movable tray pull-out operation as the operation of the sheet stacking movable means for moving the sheets stacked on the stacking surface in the same direction as the movable tray pull-out direction, and the pulled-out movable tray is transmitted again. The movable tray and the sheet stacking movable means are engaged so that the pushing operation is not transmitted as the operation of the sheet stacking movable means for moving the sheets stacked on the stacking surface.

  According to the present invention, since the sheet on the stacking surface of the sheet stacking movable means is moved and pulled out together with the movable tray together with the pulling out of the movable tray, the sheet can be taken out very easily. Even when the sheet discharging operation is performed while the movable tray is pulled out, the sheets are stably stacked on the stacking surface. Even if the movable tray is pushed in after that, the sheets stacked on the stacking surface are not moved, so that the occurrence of problems such as bending, rubbing and jamming of those sheets can be suppressed.

1 is a schematic diagram illustrating an internal configuration of a printer having a sheet stacking apparatus according to an embodiment of the present invention. It is the schematic explaining the operation | movement at the time of the single-sided printing by the printer shown in FIG. It is the schematic explaining the operation | movement at the time of double-sided printing by the printer shown in FIG. FIG. 3 is a perspective view illustrating a discharge tray of the sheet stacking apparatus according to the embodiment of the present invention. It is a perspective view which shows the state which pulled out the movable tray of the discharge tray shown in FIG. It is sectional drawing which shows the state which pulled out the movable tray of the discharge tray shown in FIG. It is sectional drawing which shows the state which pulled out the movable tray of the discharge tray shown in FIG. FIG. 5 is a perspective view showing sheet stacking movable means of the discharge tray shown in FIG. 4. FIG. 5 is a cross-sectional view illustrating a state in which a large number of sheets are stacked on the stacking surface of the sheet stacking movable unit of the discharge tray illustrated in FIG. 4.

  Hereinafter, embodiments of the present invention will be described. In this embodiment, a sheet stacking device is provided in an ink jet printer. This printer is a high-speed line printer capable of both single-sided printing and double-sided printing on a continuous sheet made of paper, synthetic resin or the like and wound into a roll. The continuous sheet after printing is cut into a predetermined size. Are discharged. This printer is particularly suitable for a large amount of printing in a print laboratory or the like.

  FIG. 1 is a schematic diagram showing the internal configuration of the printer. Inside the printer, the following units are mainly provided along a sheet conveyance path indicated by a solid line. As a unit for supplying a continuous sheet, printing, and cutting, a sheet supply unit 1, a decurling unit (warp reduction unit) 2, a skew correction unit 3, a printing unit 4, an inspection unit 5, and a cutter unit 6 is provided. An information recording unit 7, a drying unit 8, a sheet take-up unit 9, a discharge conveyance unit 10, and a sorting unit 11 are provided as mechanisms for conveying the cut sheet and sorting and discharging it. . Further, a control unit 13 for controlling the operation of each unit of the printer is provided. The sort unit 11 includes a tray group. In the present embodiment, the tray group is, for example, a large-size sheet discharge tray 12, a large-size sheet large-capacity discharge tray 18, a small-size sheet discharge tray 17, and an unnecessary sheet. Used separately from the discharge tray 19. Many of the units are provided with a sheet conveying mechanism including a roller pair and a belt, and the sheets are conveyed along the sheet conveying path by these sheet conveying mechanisms, and each unit performs respective processing. .

  The sheet supply unit 1 is a unit that stores and supplies a continuous sheet wound in a roll shape. The sheet supply unit 1 of the present embodiment can store two rolls R1 and R2, pulls out a sheet from one of these rolls R1 and R2, and supplies it to the subsequent units. However, the number of rolls that can be stored in the sheet supply unit 1 is not limited to two, and only one roll may be stored, or three or more rolls may be stored.

  The decurling unit 2 is a unit that reduces curling (warping) of the sheet supplied from the sheet supply unit 1. The decurling unit 2 is provided with one driving roller and two pinch rollers in contact with both sides thereof. The supplied sheet is passed between the drive roller and one of the pinch rollers, and the sheet is bent and curled so as to give a curl in the opposite direction to the curl generated by being rolled. This reduces curl. One of the two pinch rollers is selected and used according to the direction of warpage.

  The skew correction unit 3 is a unit that corrects the skew of the sheet that has passed through the decurling unit 2 (that is, the sheet moves while being inclined with respect to the original traveling direction). The skew of the sheet is corrected by pressing it against the guide member with one of both side end portions of the continuous sheet as a reference.

  The printing unit 4 is a unit that prints (forms an image) on the conveyed sheet by the print head 14. The printing unit 4 includes a plurality of print heads 14 arranged in parallel along the conveyance direction, and a plurality of conveyance rollers that convey the sheet. The print head 14 is a line type print head in which an inkjet nozzle row is formed in a range that covers the maximum width of a sheet that is supposed to be used. In this embodiment, seven print heads corresponding to seven colors of C (cyan), M (magenta), Y (yellow), LC (light cyan), LM (light magenta), G (gray), and K (black). Have However, the number of colors and the number of print heads are not limited to seven. As the ink jet method, a method using a heating element, a method using a piezo element, a method using an electrostatic element, a method using a MEMS (Micro Electro Mechanical Systems) element, or the like can be employed. Each color ink is supplied from an ink tank (not shown) to each print head 14 via an ink tube.

  The inspection unit 5 includes an optical element, and optically reads an inspection pattern or an image formed on the sheet by the printing unit 4 to inspect the nozzle state of the print head, the sheet conveyance state, the image position, and the like. It is.

  The cutter unit 6 has a mechanical cutter and is a unit that cuts a printed sheet into a predetermined length. The cutter unit 6 also includes a plurality of conveying rollers for sending the cut sheet to the next process.

  The information recording unit 7 is a unit that has a print mechanism and records print information such as a serial number and date on the back surface (unprinted surface) of the cut sheet. The printing mechanism of the information recording unit 7 may be the same as that of the print head 14 of the printing unit 4, but may be of a smaller and simpler configuration. Further, the printing mechanism is not limited to the ink jet system, and may operate in a simpler system. As will be described later, in the case of double-sided printing, the information recording unit 7 does not operate.

  The drying unit 8 has a dryer and is a unit that heats the sheet printed by the printing unit 4 and dries the attached ink in a short time. The drying unit 8 also includes a conveyance belt and a conveyance roller for sending the sheet to the next process.

  The sheet winding unit 9 is a unit that temporarily winds a continuous sheet on which printing on the front surface has been completed when performing double-sided printing. The sheet winding unit 9 includes a rotatable winding drum for winding a sheet. In the case of double-sided printing, the continuous sheet is conveyed without being cut when only the front surface is printed. The continuous sheet is temporarily wound around the winding drum in the sheet winding unit 9. When the winding is completed, the winding drum rotates reversely, and the wound sheet is supplied to the decurling unit 2 and sent to the printing unit 4 (the conveyance path at this time is indicated by a dotted line). Since the continuous sheet drawn again from the winding drum is reversed, the printing unit 4 can print on the back side. More specific operation during duplex printing will be described later.

  The discharge conveyance unit 10 is mainly composed of a pair of rollers, and is a sheet cut by the cutter unit 6 and dried by the drying unit 8 (in the case of double-sided printing, after being printed, cut, and dried on the back side) This is a unit for transporting sheets) and delivering the sheets to the sorting unit 11.

  The sort unit 11 constitutes a main part of the sheet stacking apparatus of the present invention, and is a unit that discharges printed sheets in groups as necessary. In this embodiment, the tray group is divided into a large size sheet discharge tray 12, a small size sheet discharge tray 17, a large size sheet large capacity discharge tray 18, and an unnecessary sheet discharge tray 19. The sheets are grouped in the sorting unit 11, sorted for each group, and discharged to one of the trays.

  The control unit 13 is a unit that controls each unit of the printer. The control unit 13 includes a CPU, a memory, a controller 15 having various I / O interfaces, and a power source. Only the controller 15 is shown in the drawing. An external device 16 such as a host computer is connected to the controller 15 via an I / O interface. The operation of the printer is controlled based on a command from the controller 15 or the external device 16.

  Next, the basic operation during printing by this printer will be described. Since the printing operation differs between single-sided printing and double-sided printing, each will be described.

  FIG. 2 is a diagram for explaining the operation during single-sided printing. First, a continuous sheet is supplied from the sheet supply unit 1, the warping is reduced by the decurling unit 2, and the skew is corrected by the skew correcting unit 3, and then printed on the surface by the printing unit 4. The printed continuous sheet is inspected by the inspection unit 5 and then cut by the cutter unit 6 for each predetermined length. The control unit 13 controls the printing unit 4 and the cutting unit 6 so that a predetermined range cut by the cutting unit 6 and a print area by the printing unit 4 substantially coincide with each other. Print information is recorded on the back side of the cut sheet (cut sheet-like sheet) by the information recording unit 7 as necessary. Then, the cut sheet-like sheets are conveyed one by one to the drying unit 8 and dried. Thereafter, the sheet is conveyed to the sorting unit 11 via the discharge conveyance unit 10. In the sorting unit 11, sorting is performed based on control by the control unit 13. Specifically, according to the size of the cut sheet-like sheet, a large size sheet is discharged to the large size sheet discharge tray 12, and a small size sheet is discharged to the small size sheet discharge tray 17. However, when it is known that large sized sheets are produced in large quantities, the large sized sheets are discharged to the large sized sheet large capacity discharge tray 18 instead of the large sized sheet discharge tray 12. Unnecessary sheets such as a test-printed sheet, a sheet in which a print defect has occurred, a margin portion positioned between the sheets, and the like are discharged to the unnecessary sheet discharge tray 19. Note that the grouping method in the sorting unit and the method for selectively discharging the grouped sheets to one of the trays may be any conventionally known method, and thus the description thereof is omitted. What kind of grouping is performed in the sorting unit may be appropriately determined. The present invention is also effective when the tray to be discharged is changed sequentially in accordance with the number of sheets.

  FIG. 3 is a diagram for explaining the operation during duplex printing. In the case of double-sided printing, the front side printing sequence is first performed, and then the back side printing sequence is executed. In the front surface printing sequence, the operations in the units from the sheet supply unit 1 to the decurling unit 2, the skew correction unit 3, the printing unit 4, and the inspection unit 5 are the same as those of the single-sided printing sequence described above. . At this point, the cutting of the sheet by the cutter unit 6 and the recording by the information recording unit 7 are not performed, but the continuous sheet passes through the cutter unit 6 and the information recording unit 7 and is conveyed to the drying unit 8. The drying unit 8 dries the ink on the surface of the sheet. Thereafter, the sheet is introduced not from the drying unit 8 to the discharge conveyance unit 10 but to the route to the sheet winding unit 9. In this way, the sheet introduced into the path toward the sheet winding unit 9 is wound around the winding drum of the sheet winding unit 9 that rotates in the forward direction (counterclockwise direction in the drawing). In addition, switching of the path | route of the sheet | seat which passed the drying part 8 is performed by the well-known method using the guide member etc. which are not shown in figure.

  When all the scheduled printing on the surface of the sheet is completed in the printing unit 4, the continuous sheet is cut by the cutter unit 6 at the position of the rearmost end of the entire printing area. The continuous sheet downstream of the cutting position in the conveying direction (continuous surface-printed continuous sheet) passes through the drying unit 8 and is all wound up to the sheet end (cut position) by the sheet winding unit 9. On the other hand, the continuous sheet upstream of the cutting position in the conveyance direction (continuous sheet not printed on the front surface) is rewound to the sheet supply unit 1 so that a part of the sheet does not remain in the decurling unit 2 or the like.

  After the front surface printing sequence described above, the process proceeds to the back surface printing sequence. Specifically, the winding drum of the sheet winding unit 9 that has wound the continuous sheet to the last end rotates in the opposite direction (clockwise direction in the drawing) to that during winding. As a result, the end of the wound sheet (the last end of the sheet at the time of winding becomes the leading edge of the sheet at the time of re-feeding) is fed into the decurling unit 2. This conveyance path is indicated by a dotted line in the drawing. The decurling unit 2 performs curl correction in the opposite direction to that when the continuous sheet is supplied from the sheet supply unit 1. This is because the continuous sheet wound around the take-up drum is wound upside down from the roll of the sheet supply unit 1 and is curled in the opposite direction. The continuous sheet (surface-printed continuous sheet) whose warpage has been reduced by the decurling unit 2 is corrected in skew by the skew correcting unit 3 and sent to the printing unit 4 again. Printing is performed on the back surface of the continuous sheet by the print head 14 of the printing unit. The continuous sheet printed also on the back surface is inspected by the inspection unit 5 and then cut by the cutter unit 6 for each predetermined length. Since the sheet cut in this way (cut sheet-like sheet) is printed on both sides, recording by the information recording unit 7 is not performed. The cut sheet-like sheets are conveyed one by one to the drying unit 8, dried, and conveyed to the sorting unit 11 via the discharge conveyance unit 10. In the sort unit 11, the sort is performed based on the control by the control unit 13, as in the above-described front surface print sequence. That is, a large-size sheet is placed in the large-size sheet discharge tray 12 (a large-size sheet large-capacity discharge tray 18 when there are a large number of sheets), a small-size sheet is placed in the small-size sheet discharge tray 17, and unnecessary sheets are unnecessary sheets. Each is discharged to a discharge tray 19.

  Next, the structure of the discharge tray in the sheet stacking device of the printer of this embodiment will be described in more detail. In the following description, the unnecessary sheet discharge tray 19 will be described as an example.

  4 to 7 are schematic views illustrating the configuration of the unnecessary sheet discharge tray 19 of the present embodiment. The unnecessary sheet discharge tray 19 of the present embodiment is provided to face the discharge roller 22 constituting the sheet discharge unit of the sorting unit 11, and includes a sheet stacking movable unit 20, a guide member 21, and a movable tray 23. Yes. The guide member 21 is a hollow quadrangular frame-like member, and the sheet stacking movable means 20 is disposed therein. The sheet stacking movable unit 20 has a stacking surface (upper surface of an endless belt 33 described later) on which a cut sheet-like sheet P discharged from the discharge roller 22 of the sorting unit 11 can be stacked, and the stacking surface is a guide member. It is possible to move in one direction (in the direction of arrow A in FIGS. The four surfaces of the guide member 21 and the stacking surface of the sheet stacking movable means 20 form a tray shape with the top opened. This corresponds to the upper tray. That is, in this tray shape (upper tray), the stacking surface of the sheet stacking movable means 20 is the bottom surface, and the four surfaces of the guide member 21 are the four wall surfaces.

  On the other hand, the movable tray 23 corresponding to the under tray has a shape in which an upper portion and one side portion are opened. Except for the opened one side portion, the four surfaces of the guide member 21 and the stacking surface of the sheet stacking movable means. The tray shape (upper tray) comprised by these is enclosed. The bottom surface of the movable tray is located below the sheet stacking movable means 20. The movable tray 23 can be pulled out in the direction opposite to the opened one side, that is, in the same direction as the stacking surface of the sheet stacking movable means 20 (arrow A direction). The sheet stacking movable unit 20 and the movable tray 23 are not fixed with respect to the guide member 21 that cannot move, and the stacking surface of the sheet stacking movable unit 20 can be independently moved in the A direction. Can be independently pulled out in the A direction.

  The sheet conveying unit 20 will be described in more detail. FIG. 8 is a perspective view showing the configuration of the sheet stacking movable unit 20 in detail. Between a pair of mounting plates 32 fixed to the frame of the printer and the guide member 21, two round bars 29, 31 are mounted in parallel and rotatably. The round bar 29 includes a gear-like interlocking portion 25 and a belt roller 27, and the round bar 31 includes a belt roller 30. An endless belt 33 whose upper surface is the stacking surface of the sheet stacking movable unit is hung on the belt roller 27 and the belt roller 30. In addition, a short round bar 28 is rotatably attached in parallel with the round bar 29, and a gear-like interlocking part (another interlocking part) 24 provided on the round bar 28 is provided on the round bar 29. The gear-like interlocking portion 25 is meshed with a not-shown one-way clutch mechanism. Accordingly, the interlocking unit 24 transmits only rotation in one direction, specifically, the clockwise direction (the direction of arrow B in FIG. 6) to the interlocking unit 25, and the counterclockwise direction of the interlocking unit 25 (the direction of arrow C in FIG. 6). ). Due to the one-way clutch mechanism, the interlocking part 24 does not transmit the counterclockwise rotation to the interlocking part 25, and the interlocking part 25 does not rotate clockwise. As a result, the upper surface (loading surface) of the endless belt 33 can move in the direction of arrow A in FIGS. 5 and 6, but does not move in the opposite direction.

  The interlocking mechanism for engaging the sheet stacking movable means 20 and the movable tray 23 will be described in more detail. As shown in FIG. 6, a rack 26 is formed on the bottom surface of the movable tray 23 although a detailed tooth shape is not shown, and this rack 26 is a gear-like interlocking portion 24 of the sheet stacking movable means 20. Are engaged. Accordingly, the rack 26 of the movable tray 23 meshes with the interlocking portion 24 of the sheet stacking movable means 20, and the interlocking portion 24 meshes with the interlocking portion 25 via the one-way clutch mechanism.

  With this configuration, when the movable tray 23 is pulled out in the direction of arrow A in FIGS. 5 and 6 from the state in which the movable tray 23 is accommodated as shown in FIG. 24 rotates in the direction of arrow B in FIG. 6, and the interlocking unit 25 further rotates in the direction of arrow C. The belt roller 27 provided concentrically with the interlocking portion 25 rotates in synchronization with the interlocking portion 25, and the endless belt 33 rotates. As a result, the upper surface (stacking surface) of the endless belt 33 moves in the arrow A direction. Accordingly, the sheets P stacked on the upper surface (stacking surface) of the endless belt 33 are moved simultaneously with the movable tray 23 and can be easily taken out by the user. When the movable tray 23 is completely pulled out as shown in FIG. 7, the sheet P can be taken out more easily.

  When the sheet P is discharged from the discharge roller 22 in a state where the movable tray 23 is pulled out as shown in FIGS. 5 and 6 or in a state where the movable tray 23 is completely pulled out as shown in FIG. The sheets P are stacked on the upper surface (stacking surface) of the endless belt 33. When the movable tray 23 pulled out is stopped or the movable tray 23 is removed, the interlocking portion 24 and the interlocking portion 25 do not rotate, so the endless belt 33 does not rotate, and the sheet P does not rotate the endless belt 33. Stacks neatly on the top surface (loading surface). Thereafter, when the movable tray 23 is pushed in the direction opposite to the arrow A, the rack 26 moves and the interlocking portion 24 rotates in the direction opposite to the arrow B (counterclockwise). However, since the rotation of the interlocking portion 24 is not transmitted to the interlocking portion 25 by the one-way clutch mechanism, the endless belt 33 does not move. Accordingly, the sheets P stacked on the upper surface (stacking surface) of the endless belt 33 are held as they are without being moved. That is, even when the movable tray 23 that has been pulled out is pushed in again, the sheet P discharged onto the upper surface (stacking surface) of the endless belt 33 while the movable tray 23 is pulled out is movable. The tray 23 is not moved along with the pushing operation. Therefore, the movement of the sheet P does not cause damage to the printing surface due to jamming or rubbing.

  Here, for convenience, only the unnecessary sheet discharge tray 19 has been described as an example, but it is preferable that all the discharge trays of the tray group have the same configuration.

  As described above, in the discharge tray of the sheet stacking apparatus of the present invention, the rack 26 provided on the movable tray 23 rotates in synchronization with the belt roller 27, the one-way clutch mechanism (not shown), and the other one. It is connected via the interlocking unit 24. Thereby, the pulling operation of the movable tray 23 is transmitted as the operation of the endless belt 33 that moves the sheets P stacked on the stacking surface in the same direction as the pulling direction of the movable tray 23. On the other hand, the operation of pushing the pulled-out movable tray 23 again is not transmitted as the operation of the endless belt 33 that moves the sheets P stacked on the stacking surface.

  According to this configuration, when the movable tray 23 positioned below the endless belt 33 having the stacked surface of the sheets P is pulled out, the sheet P on the stacked surface moves into the movable tray 23 and is pulled out together with the movable tray 23. The sheet P can be taken out very easily. Thereby, even if the space | interval of the trays provided in plurality is narrowed, the sheet | seat P can be taken out easily. Even if the sheet P is discharged while the movable tray 23 is pulled out, the sheets P can be stably stacked on the upper surface (stacking surface) of the endless belt 33. Furthermore, even if the movable tray 23 is pushed in after that, the sheets P stacked on the stacking surface are not moved, so that occurrence of problems such as bending, rubbing and jamming of the sheets P can be suppressed.

  FIG. 9 shows a state in which the amount of sheets P stacked on the stacking surface of the sheet stacking drive unit 20 has increased. That is, when the bundle of sheets P stacked on the stacking surface is higher than the height of the guide member 21, the sheet P discharged from the discharge roller 22 is discharged outside the guide member 21. be able to. In that case, it is preferable that the height difference L between the sheet discharge portion (nip portion) of the discharge roller 22 and the upper end surface of the guide member 21 is large.

4 Print section 11 Sort section (sheet stacking device)
19 unnecessary sheet discharge tray 20 sheet stacking movable means 21 guide member 22 discharge roller (sheet discharge means)
23 Movable trays 24, 25 Gear-like interlocking part (interlocking mechanism)
26 racks (interlocking mechanism)
27, 30 Belt roller 33 Endless belt

Claims (6)

Sheet discharge means for discharging sheets, sheet stacking movable means having a stacking surface for stacking sheets discharged by the sheet discharge means, a movable tray that is positioned below the sheet stacking movable means and can be pulled out, and the movable An interlocking mechanism that engages the tray and the sheet stacking movable means,
The interlocking mechanism transmits the operation of pulling out the movable tray as the operation of the sheet stacking movable means for moving the sheets stacked on the stacking surface in the same direction as the pulling direction of the movable tray, and is pulled out. The movable tray and the sheet stacking movable means are engaged so that the operation of pushing the movable tray again is not transmitted as the operation of the sheet stacking movable means for moving the sheets stacked on the stacking surface. A sheet stacking device characterized by being combined.   The sheet stacking apparatus according to claim 1, further comprising a frame-shaped guide member formed so as to surround the sheet stacking movable unit.   The sheet stacking apparatus according to claim 1, wherein the sheet stacking movable unit includes an endless belt, and the stacking surface is an upper surface of the endless belt.   The endless belt is hung on two belt rollers arranged in parallel, and the interlocking mechanism is provided in a rack provided in the movable tray and in the sheet stacking movable means, and the rack and the one-way clutch mechanism 4. The sheet stacking apparatus according to claim 3, further comprising: a gear-like interlocking portion connected via an intermediate member, wherein the interlocking portion rotates in synchronization with one of the belt rollers.   The interlocking mechanism further includes another gear-like interlocking part provided between the interlocking part and the rack, and the interlocking part and the another interlocking part mesh with each other via the one-way clutch. The sheet stacking apparatus according to claim 4, wherein the sheet stacking apparatus is provided.   6. A printer comprising: the sheet stacking apparatus according to claim 1; and a print unit that prints on the sheet and is located upstream of the sheet discharge unit in the sheet conveyance direction.

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