JP2007076864A - Sheet stacking device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet stacking device capable of efficiently reducing a temperature of the sheet by the minimum air stream. <P>SOLUTION: The stacking tray 18 is liftably supported relative to a box body structure 505 and a motor fan 63 blows air toward the sheets in such a state that they are loaded on the stacking tray 18. A control part 502 lifts the stacking tray 18 according to the output state of a fan switch 61 and maintains a position relationship of the sheet of the loaded uppermost position and the motor fan 63 to an approximately constant level from the first loaded sheet to the final one sheet even in any high stacking. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet stacking apparatus that stacks sheets discharged from an image forming apparatus such as a copying machine, a printer, and a multifunction peripheral, and an image forming apparatus in which the sheet stacking apparatus is mounted / connected.

  When the processed sheets discharged one by one from the image forming apparatus such as a copying machine or a printer are sequentially stacked on the stacking surface, the vertical and horizontal end surfaces are positioned and stacked, that is, aligned, and thereafter. 2. Description of the Related Art Sheet stacking devices designed for convenience such as packing, organizing, and stapler (binding) processing have been put into practical use.

  Such a sheet stacking apparatus includes a sheet stacking unit that receives and stacks sheets supplied from the upstream apparatus, and the sheets discharged to the sheet stacking unit are aligned and stacked on the sheet stacking unit.

  In recent years, an ultra-high-speed image forming apparatus exceeding 100 sheets per minute has been put into practical use, and it has been proposed that the sheet stacking apparatus is provided with a sheet cooling unit.

  That is, when a toner image is heated and fixed on a sheet by an image forming apparatus, if the sheet is stacked with incomplete cooling and the central layer being at a high temperature, the surface temperature of the sheet abnormally increases on the sheet stacking unit. It has been pointed out that the toner may be remelted to impair image quality, double-sided printed images may be fused / colored together, or sheets may be bonded together.

  In the sheet stacking apparatus that solves this problem, a fan motor is arranged on the upstream side of the sheet stacking unit to blow air on the surface of the passing sheet and to contact the back surface of the sheet with the cooling belt that is air-cooled by the fan. By doing so, both sides of the sheet are removed from heat immediately before stacking. (See Patent Document 1).

JP 2003-312920 A

  When a fan motor or a cooling belt is arranged immediately before the sheet stacking means, the sheet passes through the cooling region instantaneously, so that a sufficient cooling effect cannot be expected. In the high-speed conveyance accompanying the ultra-high-speed image formation as described above, the residence time in the cooling region is too short, and it is difficult to sufficiently cool the central layer of the sheet that is orders of magnitude thicker than the toner layer. If the sheets are stacked before the toner is completely solidified, the toner may release latent heat on the sheet stacking means, resulting in a further increase in temperature.

  Therefore, although it was considered to increase the cooling means such as increasing the size of the fan motor or adopting a refrigerator, the increase in noise and power consumption cannot be ignored if these are always operated, and the cost and layout space are secured. As a result, the sheet stacking apparatus becomes smaller and lighter, consumes less power, and becomes an obstacle to design and operability.

  An object of the present invention is to provide a sheet stacking apparatus that can efficiently reduce the temperature of a sheet with a minimum air flow.

  The sheet stacking apparatus according to the present invention is a sheet stacking apparatus having sheet stacking means for stacking sheets, wherein the sheet stacking means is supported so as to be movable up and down with respect to a casing structure, and is fixed to the casing structure and fixed to the sheet A cooling unit that blows air toward the sheets stacked on the stacking unit, a sheet detection unit that detects a height position of the sheets stacked on the sheet stacking unit, and the sheet in the stacking process. Control means for maintaining the distance between the uppermost sheet on the sheet stacking means and the cooling means substantially constant by lowering the sheet stacking means based on the output state of the detection means It is.

  In the sheet stacking apparatus of the present invention, the cooling unit cools the sheets stacked on the sheet stacking unit, so that it is easy to exert a cooling effect to the center layer of the sheet by securing more time than cooling the sheet in the transport state. In addition, since the control means raises and lowers the sheet stacking means and maintains the distance between the stacked uppermost sheet surface and the cooling means, and thus the relative positional relationship, substantially constant, the cooling means from the beginning to the end of the stacking. As compared with the case where the positional relationship between the uppermost sheet surface and the cooling means changes depending on the stacking height (see Patent Document 1), the output of the cooling means becomes excessive. As a result, a small output can be set to achieve sufficient cooling without excess or deficiency.

  Hereinafter, a sheet stacking apparatus according to an embodiment will be described with reference to the drawings. FIG. 1 is an explanatory diagram of the mechanism of the sheet stacking apparatus according to the first exemplary embodiment, FIG. 2 is a block diagram of a control system of the sheet stacking apparatus, and FIG. 3 is a flowchart illustrating the operation of the sheet stacking apparatus.

  A sheet stacking apparatus 500 according to an embodiment of the present invention is installed on the downstream side of a copier 501 that is an image forming apparatus. The sheet stacking apparatus 500 includes, for example, a stacking tray 18 that is a sheet stacking unit according to the present invention, a fan motor 63 that is a cooling unit according to the present invention, a fan switch 61 that is a sheet detection unit according to the present invention, and the like. For example, the control unit 502 and the main controller 511 which are control means are provided, and the fan motor 63 is operated while the fan switch 61 is detecting the stacking tray 18, and the fan motor 63 is stopped when the fan switch 61 is not detecting.

  As shown in FIG. 1, the sheet S supplied to the sheet stacking device 500 is fed to the upper transport path PU and the lower transport path PD according to the inclination of the flapper 13 driven by the solenoid 14 at the upper right in the drawing. It is distributed to. Then, the sheet S proceeding to the transport path PU is stacked on the upper stacking tray 18, and the sheet S proceeding to the lower transport path PD is stacked on the lower stacking tray 37.

  A base portion of the upper stack tray 18 is fixed to the tray base 44, and guide rollers 46 and 47 rotatably attached to the tray base 44 are engaged with the guide rail GU. The timing belt 54 connected to the tray base 44 is driven from a tray motor 56 via a timing belt 58, a worm gear 50, and a worm wheel 51. When the tray motor 56 drives the timing belt 54, the tray base 44 and the stacking tray 18 are moved up and down together with the guide rollers 46 and 47 guided by the guide rail GU.

  On the other hand, the base of the lower stacking tray 37 is fixed to the tray base 45, and guide rollers 48 and 49 rotatably attached to the tray base 45 are engaged with the guide rail GD. The timing belt 55 connected to the tray base 45 is driven from a tray motor 57 via a timing belt 59, a worm gear 52, and a worm wheel 53. When the tray motor 57 drives the timing belt 55, the tray base 45 and the stacking tray 37 are moved up and down together with the guide rollers 48 and 49 guided by the guide rail GD.

  The sheet S conveyed on the upper conveyance discharge path PU is driven by the conveyance drive motor 6 to rotate, and the inlet roller 1 and the driven roller 2. The sheet discharge roller 11 driven by the discharge drive motor 7 and rotated are driven. It is conveyed by the rollers 12 and discharged to the sky above the stacking tray 18. The rotation of the conveyance drive motor 6 is transmitted to the inlet roller 1 through the timing belts 5 and 3, and the driven roller 2 is in pressure contact with the inlet roller 1. The rotation of the discharge drive motor 7 is transmitted to the paper discharge roller 11 through the timing belts 8 and 10, and the driven roller 12 is in pressure contact with the paper discharge roller 11.

  An inlet sensor S1 is disposed on the upstream side of the flapper 13, and detects the leading edge and trailing edge of the sheet S sent from the copying machine 501 to the sheet stacking apparatus 500. A paper discharge sensor S <b> 2 is provided on the upstream side of the paper discharge roller 11, and detects the front and rear ends of the sheets S discharged to the stacking tray 18. When the sheet discharge sensor S2 detects the trailing edge of the sheet S, the paddle motor 16 is activated and the flexible paddle 17 starts to rotate counterclockwise in the drawing.

  Each time the sheet S is discharged from the illustrated position, the paddle 17 rotates once and stops at the illustrated position, contacts the sheet S discharged onto the stacking tray 18 during the rotation process, and bends and deforms itself. The upper surface of the sheet S is rubbed while being received, and the sheet S is swept between the knurled belt 19 and the stacking tray 18. At this time, the knurled belt 19 has already been rotated counterclockwise in the drawing in conjunction with the sheet discharge roller 11 by the timing belt 10, and the sheet S swept by the paddle 17 is abutted against the stacking wall portion 20. The rear ends of the sheets S are aligned.

  A fan switch 61 that is fixed to the housing structure of the sheet stacking device 500 and that is turned on by contacting the stacking surface of the stacking tray 18 is disposed. When the stacking tray 18 is lowered and the contact between the stacking surface and the fan switch is lost. It is arranged to turn off.

  The sheet S is pushed between the stacking tray 18 and the fan switch 61 in the process of being driven by the paddle 17 and the knurled belt 19 and moving the sheet S toward the stacking wall portion 20 on the stacking tray 18. Even when the stacking tray 18 is gradually lowered in the stacking process of the sheets S, the fan switch 61 is always in the ON state because it is always in contact with the stacked uppermost sheet S.

  A fan motor 63 is attached to the inside of the housing cover that houses the paddle 17. The fan motor 63 sucks air from above and blows it downward. The lower part of the housing cover is opened, and the paddle 17 is a thin rod that does not block the airflow. It spreads and the whole upper surface of the sheet | seat S can be cooled substantially uniformly.

  Further, the sheet S conveyed on the lower conveyance conveyance path PD is driven by the conveyance drive motor 6 to rotate, the entrance roller 21, the vertical path first roller 24, the vertical path second roller 27, and the driven roller 22, 25, 28, and the discharge roller 30 and the driven roller 31 that are driven and rotated by the discharge drive motor 7, and are discharged to the sky above the lower stacking tray 37.

  The rotation of the conveyance drive motor 6 is transmitted to the inlet roller 21 via the timing belt 5, the rotation of the inlet roller 21 is transmitted to the vertical path first roller 24 via the timing belt 23, and the vertical path first roller 24 is further rotated. The rotation is transmitted to the vertical path second roller 27 via the timing belt 26. The driven rollers 22, 25, and 28 are in pressure contact with the inlet roller 21, the vertical path first roller 24, and the vertical path second roller 27, respectively. The rotation of the discharge roller 11 driven by the discharge drive motor 7 is transmitted to the discharge roller 30 via the timing belt 29, and the driven roller 31 is in pressure contact with the discharge roller 30.

  A longitudinal path first sensor S3 is disposed between the entrance roller 21 and the longitudinal path first roller 24, and a longitudinal path second sensor S4 is disposed between the longitudinal path first roller 24 and the longitudinal path second roller 27, respectively. Then, the leading edge and the trailing edge of the sheet S conveyed along the conveyance path PD are detected. A paper discharge sensor S5 is disposed on the upstream side of the paper discharge roller 30, and detects the leading edge and the trailing edge of the sheet S discharged to the stacking tray 37. When the sheet discharge sensor S5 detects the trailing edge of the sheet S, the lower paddle motor 33 is activated and the flexible paddle 34 starts to rotate counterclockwise in the drawing.

  Each time the sheet S is discharged from the illustrated position, the paddle 34 rotates once and stops at the illustrated position, contacts the upper surface of the sheet S discharged to the stacking tray 37 during the rotation process, and bends to itself. While being deformed, the upper surface of the sheet S is rubbed to sweep the sheet S between the knurled belt 36 and the stacking tray 37. The knurled belt 36 has already been rotated counterclockwise in the drawing in conjunction with the paper discharge roller 30 by the timing belt 40, and the sheet S is brought into contact with the stacking wall portion 38 to align the rear ends of the sheets S.

  A fan switch 62 that is fixed to the housing structure of the sheet stacking device 500 and that is turned on by contacting the stacking surface of the stacking tray 37 is disposed. When the stacking tray 37 is lowered and the contact between the stacking surface and the fan switch is lost. It is arranged to turn off. The sheet S is pushed between the stacking tray 37 and the fan switch 62 in the process of being driven by the paddle 34 and the knurled belt 36 on the stacking tray 37 and moving toward the stacking wall 38. Even when the stacking tray 37 is gradually lowered in the stacking process of S, the fan switch 62 is always in the ON state because it is always in contact with the stacked uppermost sheet S.

  A fan motor 64 is attached to the inside of the housing cover that houses the paddle 34. The fan motor 64 sucks air from above and blows it downward. The lower part of the housing cover is opened, and the paddle 34 is a thin rod that does not obstruct the airflow. Therefore, the airflow of the fan motor 64 is blown onto the upper surface of the sheet S throughout the rotation of the paddle 34 and along the sheet S It spreads and the whole upper surface of the sheet | seat S can be cooled substantially uniformly.

  As shown in FIG. 2, the control unit 502 disposed at the lower part of the sheet stacking apparatus 500 includes an inlet sensor S1, paper discharge sensors S2 and S5, a first vertical path sensor S3, a second vertical path sensor S4, a fan switch 61, 62, etc. and the content of the command from the main controller 511, the conveyance drive motor 6, the discharge drive motor 7, the tray motors 56, 57, the paddle motors 16, 33, the solenoid 14 and the like are controlled to carry, The operations of discharging, aligning, loading, and raising / lowering the loading trays 18 and 37 are executed in a harmonious manner. The main controller 511 communicates with the copier 501 to control the start and end of loading, and supplies power to the fan motors 63 and 64 according to the ON / OFF state of the fan switches 61 and 62 received from the control unit 502. By turning on / off the switching power supply 519, the fan motors 63 and 64 can be individually activated / stopped.

  2, the control unit 502 includes a CPU 510, input / output circuits 516 and 517, a drive unit (driver) 518, a ROM 512, a RAM 514, an EEPROM 515, and the like.

  The ROM 512 stores a control program for the sheet stacking apparatus 500 and various necessary data. The RAM 514 stores information necessary for executing the operation sequence, and is also used as a working memory. The CPU 510 reads the output states of the various sensors described above through the input / output circuit 516, reads the transmission data of the main controller 511, performs necessary calculations, and writes the calculation results in the input / output circuit 517. The calculation result is reflected on the operation / stop of the above-described various motors and actuators through the driver 518, and the above-described loading and alignment operations are realized.

  The sheet stacking apparatus 500 configured as described above executes stacking / alignment and cooling of the sheets S according to the sequence program shown in the flowchart of FIG. Here, in order to avoid duplication and complication, a case where stacking is performed on the upper stacking tray 18 will be described. However, the stacking / alignment and cooling of the sheets S are similarly performed on the lower stacking tray 37.

  As shown in FIG. 3, when a request signal for carrying-in permission is received from the copying machine 501, the stacking sequence is started. In step S201, sheet information sent from the copying machine 501 is acquired. In step S202, it is determined whether or not the fan switch 61 is ON, that is, whether or not the stacking tray 18 is at a height position where stacking / alignment can be started. If the fan switch 61 is not turned on, the stacking tray 18 is raised to the height at which it is turned on. However, if the fan switch 61 is ON, stacking / alignment can be started, so the main controller 511 shown in FIG. 2 sends a sheet carry-in permission signal to the copier 501 in step S203, and the fan motor 63 in the subsequent step S205. Start up.

  Then, the sheet S starts to be carried from the copying machine 501 in step S206. Since the sheet S is pushed between the stacking tray 37 and the fan switch 62, even if the stacking tray 37 is gradually lowered in the process of stacking the sheet S, the fan switch 62 always contacts the uppermost sheet S stacked. Because it is doing, it will keep turning on. In this way, the positional relationship between the discharge roller 11 and the uppermost sheet S, the positional relationship between the paddle 17 and the upper surface of the uppermost sheet S, and the positional relationship between the knurled belt 19 and the uppermost sheet S are constant. Maintained.

  When the last sheet S is completely stacked on the stacking tray 18 in step S207, the cooling time is calculated in step S208 according to the number of stacked sheets in the first acquired sheet information. In step S209, it is determined whether or not the calculated cooling time has elapsed. Until this time elapses, the process proceeds to step S221, and the stacking tray 18 is kept on standby with the fan switch 61 turned on. Thereafter, when the cooling time elapses, the process proceeds to step S210, and the stacking tray 18 is lowered to the bottom so that the operator can easily take out the stacked sheet bundle.

  As a result, a space is created between the sheet S on the stacking tray 37 and the fan switch 62, the fan switch 62 is turned OFF, and the fan motor is stopped in step S212.

  In the sheet stacking apparatus 500 configured as described above, a sufficient cooling effect can be achieved only by the fan motor 63, so that energy saving and life extension of the fan motor 63 are realized. Since the sheet S discharged from the copying machine 501 is directly cooled by operating the fan motor 63, it is possible to prevent the sheets from adhering (discharging adhesion) due to remelting of the toner. The entire copying machine system configured by the stacking apparatus 500 can always provide stable and high-quality images. Further, since the sheet S is cooled by the sheet stacking device 500, the cooling time can be secured longer than the case where the copier 501 is provided with an air cooling device, and the shortage of the cooling time can be compensated. As a result, the processing speed of the copying machine 501 can be further increased.

  Further, as shown in FIG. 1, the stacking tray 18 supported so as to be movable up and down with respect to the housing structure 505, and the fan motor 63 that is fixed to the housing structure 505 and blows air toward the stacked sheets S. Therefore, a sufficient cooling time is secured and the cooling effect is easily exerted to the center layer of the sheet as compared with the case where the sheet S in the transported state is cooled (see Patent Document 1).

  Further, the fan switch 61 that detects the height position of the sheet S to be stacked from now on, and the stacking tray 18 is moved up and down based on the output state of the fan switch 61, so that the position of the topmost sheet S and the fan motor 63 is stacked. Since the control unit 502 that maintains the relationship almost constant is provided, a substantially constant cooling effect by the fan motor 63 can be expected from the first stack to the last stack regardless of how high the stack is. As a result, the output of the fan motor 63 may become excessive or insufficient as compared with the case where the positional relationship between the uppermost sheet surface and the cooling unit changes depending on the stacking height (see Patent Document 1). As a result, a small output can be set. Since a sufficient cooling effect can be secured with a small air volume, the airflow generated by the fan motor 63 does not significantly affect the discharge of the sheet S by the discharge roller 11 and the alignment of the sheet S by the paddle 17.

  Further, since the fan motor 63 is activated when the stacking of the sheets S on the stacking tray 18 is started, the fan motor 63 operates meaninglessly before the stacking starts and does not generate unnecessary power consumption and noise.

  Since the fan motor 63 is activated when the sheet information is acquired from the copying machine 501, the fan motor 63 is started up using the time until the actual supply is started, and the airflow state is stabilized on the stacking tray 18. Thus, it is possible to reduce the variation in the discharge / alignment of the sheets S due to the disturbance of the airflow state.

  In addition, since the fan motor 63 is stopped after a lapse of a predetermined time after the end of loading, the cooling effect can be enhanced as compared with the case of stopping immediately after the end of loading.

  Further, the fan motor 63 is operated when the fan switch 61 is turned on regardless of the control of the control unit 502, is stopped when the fan switch 61 is turned off, and when the control unit 502 lowers the stacking tray 18 after the stacking is finished, Since the fan motor 63 is automatically stopped, the configuration, program, wiring, and the like of the control unit 502 can be configured in common for models with and without the fan motor 63 installed.

  In addition, since the fan motor 63 is employed so that the airflow is blown vertically onto the upper surface of the sheets S on the stacking tray 18, the airflow can be exerted on a relatively large area with little variation, and the discharged sheets are discharged. Flapping and slipping are suppressed when the air current is pushed to the stacking tray 18 and the discharge / alignment is smoothly performed as compared with the case where the air current is blown obliquely.

  Further, since the discharge roller 11 and the driven roller 12 discharge the sheet at a height position fixed to the housing structure 505, the stacking unit 18 is lifted and lowered by the control unit 502 regardless of how high the stacking is performed. Compared to the case where the relationship between the stack height of the sheet S to be discharged and the discharge height is almost constant from the first to the last sheet, and this relationship changes according to the stack height (see Patent Document 1). Thus, the drop position of the discharged sheet S can be less disturbed, and the amount of movement for alignment can be reduced.

  Further, since the paddle 17 that rotates at a height position fixed to the housing structure 505 and moves the sheet S to a position where it contacts the stacking wall portion 20 in contact with the sheet S in the rotation process is provided. Even in such a case, the positional relationship between the aligned sheet S and the paddle 17 is maintained almost constant from the first stack to the last stack, and this relationship changes according to the stack height (see Patent Document 1). In comparison, the alignment state becomes uniform, and the required level for the shape, quality and control of the paddle 17 is lowered.

  Since the sheet stacking apparatus 500 that is optimal for sheet cooling is mounted, the reliability and image quality of the copying machine system (an example of an image forming apparatus) including the copying machine 501 are improved, and the processing speed is further improved. Is also possible.

  In the sheet stacking apparatus 500, the fan motor 63 that forms an air flow at room temperature is used as a cooling means. However, a cool air may be blown in combination with a heat pump cooler. You may employ | adopt the various distance measuring apparatus regardless of a contact.

  Further, in the present embodiment, control is performed in which the stacking tray 18 (37) is gradually lowered and the fan switch 61 (62) is kept on as the sheets S are stacked, but once every five sheets are stacked, for example. The stacking tray 18 (37) may be lowered to a height position at which the fan switch 61 (62) is turned off, and then immediately reversed and raised to stop at a height position at which the fan switch 61 (62) is turned on. . In this case, even if the fan switch 61 (62) is turned off, the control unit 502 has not yet finished sheet stacking (S207 in FIG. 3), so the fan motor 63 (64) continues to rotate.

  Also, the fan switch 61 (62) is not a simple ON / OFF switch, and the topmost sheet height (the height of the stacking tray 18 (37) when not stacked) is OFF within a predetermined range. Alternatively, a switch circuit may be used in which the output voltage is inverted by turning the output voltage on and off when the output voltage is higher than the predetermined range and lower than the predetermined range.

  In this case, the output of the fan switch 61 (62) is controlled to lower the stacking tray 18 (37) when the height of the uppermost sheet stack exceeds a predetermined range and to raise the stacking tray 18 (37) when the predetermined range is interrupted. It becomes possible to perform based on. As a result, it is smaller, lighter, lower in cost, and consumes less power than the case where a sensor or measuring device of a type for detecting the distance or the amount of movement is provided and the stacking tray 18 (37) is controlled to move up and down. It is reduced.

  Further, instead of controlling the copier 501 and the sheet stacking apparatus 500 by independent control apparatuses, the copier 501 and the sheet stacking apparatus 500 may be configured integrally to provide a common control apparatus. Alternatively, the sheet stacking device 500 may be controlled by a control device, or a control unit in which the main controller 502 and the control unit 511 are integrated may be provided.

  In the sheet stacking apparatus 500, power is directly supplied from the switching power supply 519 to the fan motor 63. However, a drive circuit for the fan motor 63 may be incorporated in the board of the main controller 511.

  Further, instead of turning off the fan motor 63 according to the output of the fan switch 61 in the vicinity of the stacking tray 18, a timer is counted by the CPU in the main controller 511, and the sheet S is not supplied from the copier 501 at a predetermined time. The heat of the sheet S may be sufficiently cooled by turning off the fan motor 63.

  In the sheet stacking device 500, the fan motor 63 with a fixed air volume is employed. However, since the fan motor 63 is located at a position where it can be operated from the outside of the housing structure 505, the amount of air taken in by the fan motor 63 can be varied. By providing fins or the like (variable static pressure), the operator can vary the air volume of the fan so that the air volume as required can be obtained.

  In the sheet stacking apparatus 500, the fan motor 63 is provided outside the housing structure 505. However, the fan motor 63 may be arranged at a deep position in the housing structure 505 to guide the air flow using a duct or the like.

  Further, the control unit 502 makes use of the fact that the stacking trays 18 and 37 are two stages, and alternately selects the stacking trays 18 and 37 that are the discharge stacking destination for each sheet, and is longer than the case of continuous discharge. The cooling may be performed by increasing the cooling time at intervals.

  Further, in the sheet stacking apparatus 500, there is only one fan switch 61 for operating / stopping the fan motor 63. However, depending on the application, a plurality of fan switches 61 may be provided to operate the fan motor 63 at a desired height position or at different height positions. It is also possible to stop.

  In the sheet stacking apparatus 500, the fan motor 63 is operated / stopped at the ON / OFF timing of the fan switch 61. A sheet temperature detection sensor or the like is provided to control the operation / stop of the fan motor 63. Also good.

  The present invention prevents adhesion between sheets (sheet discharge adhesion) by cooling the sheet discharged from the image forming apparatus not only in the image forming apparatus but also in a sheet post-processing apparatus such as the sheet stacking apparatus 500. The entire image forming apparatus can always provide stable and high-quality images, and the cooling means is devised to save energy and extend the life of the cooling means. It can also be used in various image forming apparatuses equipped with various sheet post-processing devices and sheet post-processing units. That is, the sheet stacking apparatus of the present invention is used even in combination with other image forming apparatuses such as a copying machine, a printer, a facsimile machine, and a multi-function machine, and can be configured by being integrated into these image forming apparatuses. is there. In addition, since the cooling unit is provided to cool the stacked sheets, the sheet is not limited to the image forming apparatus, and can be used in combination with an upstream apparatus that performs various inspections, processing, processing, and the like. Thus, the present invention is not limited to the stackable tray and the copying machine system described in the embodiment.

FIG. 3 is an explanatory diagram of a mechanism of the sheet stacking apparatus of Embodiment 1. It is a block diagram of a control system of the sheet stacking apparatus. 6 is a flowchart for explaining the operation of the sheet stacking apparatus.

Explanation of symbols

6 Transport drive motor 7 Discharge drive motor 11, 30 Discharge roller (discharge means)
12, 31 Followed roller (discharge means)
16, 33 Paddle motor (alignment means)
17, 34 Paddle (alignment means)
18, 37 Loading tray (sheet stacking means)
19, 36 Knurled belt (alignment means)
20, 38 Stacking wall portion 56, 57 Tray motor 61, 62 Fan switch (sheet detecting means)
63, 64 Fan motor (cooling means)
502 Control unit (control means)
511 Main controller (control means)
500 Sheet stacking device 501 Copier S1 Entrance sensor S2, S5 Discharge sensor

Claims (8)

In a sheet stacking apparatus having sheet stacking means on which sheets are stacked,
The sheet stacking means is supported to be movable up and down with respect to the housing structure,
Cooling means for blowing air toward the sheet in a state of being fixed to the housing structure and stacked on the sheet stacking means;
Sheet detecting means for detecting the height position of the sheet stacked on the sheet stacking means;
During the stacking process, the sheet stacking unit is lowered based on the output state of the sheet detection unit, thereby maintaining a substantially constant interval between the uppermost sheet on the sheet stacking unit and the cooling unit. Control means;
A sheet stacking apparatus comprising:   The sheet stacking apparatus according to claim 1, wherein the cooling unit is activated before starting the stacking on the sheet stacking unit.   The sheet stacking apparatus according to claim 2, wherein the cooling unit is activated when information on the sheet is acquired from a supply source side of the sheet.   4. The sheet stacking apparatus according to claim 1, wherein the cooling unit is stopped after a predetermined time elapses after the stacking ends. The sheet detection means is a switch element that reverses the output when the height position deviates from a predetermined range,
The cooling means is activated when the height position falls within the predetermined range according to the output of the switch element, and is stopped when the predetermined position deviates,
5. The sheet stacking apparatus according to claim 1, wherein the control unit lowers the sheet stacking unit to a height position where the height position deviates from the predetermined range after the stacking is finished.   The cooling means is a fan motor that is disposed above the sheet stacking means and forms an airflow that blows down vertically onto the upper surface of the sheet stacked on the sheet stacking means. The sheet stacking apparatus according to 1 to 5. Discharging means for discharging the sheet at a height position fixed to the housing structure;
An alignment unit that rotates at a height position fixed to the casing structure and moves to a predetermined position on the sheet stacking unit by contacting the sheet during the rotation process. The sheet stacking apparatus according to 1 to 6. 8. An image forming apparatus comprising an image forming device for forming an image on the sheet, comprising the sheet stacking device according to claim 1.

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