JP4598331B2 - Paper stacking apparatus and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an image forming apparatus such as a copying machine, a facsimile, and a printer, or a paper stacking apparatus such as a paper post-processing apparatus provided in the image forming apparatus., Image forming apparatus having the paper stacking deviceAbout.
[0002]
[Prior art]
In recent years, image forming apparatuses such as copying machines have been digitized, and composite image forming apparatuses having a plurality of functions such as a printer function, a copy function, and a facsimile function are increasing.
Against this background, there is an increasing need to sort by function, and the use of multiple trays is progressing in paper post-processing devices and the like. For example, Japanese Patent Application Laid-Open No. 7-76190 describes a configuration in which two paper discharge trays are provided so as to be vertically movable by individual drive sources.
Japanese Patent Application Laid-Open No. 9-48557 describes a configuration in which a tray unit that is integrally provided with three paper discharge trays is moved up and down by one drive source so that each paper discharge tray corresponds to a discharge port.
In Japanese Patent Laid-Open No. 10-310318, a tray unit that is integrally provided with three discharge trays is moved up and down by a single drive source, and each discharge tray can be individually adjusted so that the paper stacking amount can be adjusted. Describes a configuration in which it is moved up and down by another drive source.
[0003]
[Problems to be solved by the invention]
Japanese Patent Application Laid-Open No. 7-76190 has a problem in that the configuration is complicated and the cost is increased because the vertical movement mechanism and the drive source of the paper discharge tray are separately provided.
The configuration described in Japanese Patent Laid-Open No. 9-48557 is advantageous in terms of cost because there is only one drive source, but the interval between the respective discharge trays is fixed, so that the interval is the same as the maximum number of stacked sheets. Must be set. For this reason, when the assumed number of stacked sheets is large, there has been a problem that the vertical movement for making each paper discharge tray correspond to the discharge port becomes large. In addition, because of the integrated configuration, when one paper discharge tray is moved up and down, the other paper discharge trays always move at the same time. There was also a problem.
The configuration described in Japanese Patent Laid-Open No. 10-310319 has a problem that the complexity of the configuration cannot be avoided due to the large number of drive mechanisms and the cost increases.
[0004]
  The present invention relates to a paper stacking apparatus capable of reducing the configuration and reducing the cost.And image forming apparatusIs the main purpose.
[0005]
[Means for Solving the Problems]
  To achieve the above object, according to the first aspect of the present invention, a plurality of paper discharge trays for discharging sheets and the paper discharge trays are supported so as to be vertically movable over the entire moving distance. Support member and vertical driving means for moving the paper discharge tray in the vertical directionWhenIn the sheet stacking apparatus, the vertical driving means is provided so as to be shared by the plurality of paper discharge trays, and the driving force is transmitted from the vertical driving means to each of the paper discharge trays.・ Driving force switching means that can be shut off arbitrarily, and locking means that can stop and release at any positionWhenHaveThe vertical driving means includes a timing belt for moving the plurality of paper discharge trays in the vertical direction, and the driving force switching means has a timing pulley that simultaneously meshes with the timing belt, When the driving force is transmitted / blocked via the timing belt by restricting / releasing the rotation of the timing pulley and the driving force is switched by the driving force switching means, the corresponding paper discharge tray is moved to the locking means. To stop at that position, Is adopted.
[0006]
  According to a second aspect of the present invention, in the paper stacking apparatus according to the first aspect, the driving force switching means.Has a holding roller that prevents the timing belt and the timing pulley from being disengaged at a position facing the timing pulley across the timing belt., Is adopted.
[0007]
  In the invention of claim 3, claim 1 is provided.Or 2In the paper stacking apparatus, the distance measuring means for measuring the distance between the discharge trays, and the control means for controlling the vertical movement / stop of each of the discharge trays based on the measurement information of the distance measuring means.WhenIt has the structure of having.
[0008]
According to a fourth aspect of the present invention, in the paper stacking apparatus according to the third aspect, when the distance between the discharge trays is equal to or less than a predetermined value, the control means raises or lowers the discharge tray to be measured. The configuration is such that control is performed so as to be in a moving state.
[0009]
According to a fifth aspect of the present invention, in the paper stacking apparatus according to any one of the first to fourth aspects, the driving force switching means allows the upward movement of the paper discharge tray in a transmission state of the driving force. It has the structure of having.
[0010]
  According to a sixth aspect of the present invention, in the paper stacking apparatus according to any one of the first to fifth aspects, the lock unit allows the upward movement of the paper discharge tray in a stopped state. , Is adopted.
  According to the seventh aspect of the present invention, the image forming apparatus includes the paper stacking apparatus according to any one of the first to sixth aspects.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2 are overall schematic views of a finisher (paper post-processing device) as a paper stacking device, FIGS. 3 to 7 are diagrams related to a staple unit, and FIG. 8 is a paper ejected from a lower paper ejection tray. FIG. 9 is a schematic front view of the lifting mechanism of the paper discharge tray when it is set at the receiving position of the outlet E2. FIG. 9 is a view of the paper discharge tray when the upper paper discharge tray is set at the receiving position of the paper outlet E2. FIG. 10 is a perspective view of the drive mechanism, FIG. 11 is a plan view and a side view showing a state in which the upper discharge tray is movable through the discharge outlet E2, and FIG. 12 is an upper discharge tray. FIG. 13 is a perspective view showing the shift configuration of the lower discharge tray, and FIG. 14 is a perspective view showing the operation of the shift configuration of the lower discharge tray. 15 is a schematic front view showing the driving force switching means and the locking means. 6 to 18 shows the main part of the driving force switching means 19 and 20 is a diagram showing a main part of the locking means, FIG. 21 is a control block diagram.
[0012]
In FIG. 1, the discharge tray 1 as the upper discharge tray is set at the receiving position of the discharge outlet E1, and the discharge tray 2 as the lower discharge tray is set at the receiving position of the discharge outlet E2. FIG. 2 shows a state in which the paper discharge tray 2 is set in the standby position and the paper discharge tray 1 is set at the receiving position of the paper discharge port E2.
As shown in FIG. 1, an entrance sensor SN 1 and an entrance roller pair 5 are provided in the vicinity of a sheet transfer portion J between a copying machine G as an image forming apparatus and the finisher 200, and are taken in by the entrance roller pair 5. The paper sheet takes the following paper discharge form according to the post-processing mode.
(1) The sheet is discharged from the sheet discharge outlet E1 to the sheet discharge tray 1.
(2) The sheet is discharged from the sheet discharge outlet E2 to the sheet discharge tray 1 or the sheet discharge tray 2 without performing the binding process (non-staple mode).
(3) After the binding process, the paper is discharged from the paper discharge port E2 to the paper discharge tray 1 or the paper discharge tray 2 (staple mode).
[0013]
The transport route to the paper discharge port E1 is switched by a branch claw 20 provided downstream of the inlet roller pair 5, and the paper is transported by the transport roller pair 6 and discharged by the paper discharge roller pair 7. The paper discharge roller pair 7 includes a driving roller 7a and a driven roller 7b. The driven roller 7b comes into contact with the driving roller 7a by its own weight or urging force, and the paper is nipped between the rollers and discharged.
The branching claw 20 is driven by a solenoid 20a (see FIG. 21), and when the solenoid 20a is turned off, the sheet is conveyed toward the paper discharge port E1 as shown in FIG. Reference numeral SN 2 in the paper discharge route C indicates a paper discharge sensor provided in the vicinity of the paper discharge roller pair 7.
[0014]
When the solenoid 20a is turned on and the branching claw 20 is rotated upward, the sheet is guided substantially horizontally. A branching claw 21 is provided downstream of the branching claw 20, and the paper guided substantially horizontally is selectively transferred to the non-stapling route B where the binding processing is not performed or the staple route A where the binding processing is performed by the branching claw 21. Guided.
The branching claw 21 is driven by a solenoid 21a (see FIG. 21). When the solenoid 21a is turned on and rotated upward, the sheet is guided to a staple route A in a substantially vertical direction. FIG. 1 shows a state in which the solenoid 21a is turned off and transported to the non-staple route B.
[0015]
In the non-stapling route B, the sheet is conveyed by the conveyance roller pair 8 and is discharged to the discharge tray 1 or the discharge tray 2 by the discharge roller pair 9. Reference numeral SN3 denotes a paper discharge sensor in the non-staple route B and the staple route A.
In the staple route A, the sheet is transported by the transport roller pair 10 and sent to the staple unit 60 for binding processing. The bound sheets (bundle) are discharged to the discharge tray 1 or the discharge tray 2 by the discharge roller pair 9. Reference numeral SN4 in the staple route A indicates a staple discharge sensor.
The paper discharge roller pair 9 has a drive roller 9a and a driven roller 9b, and the driven roller 9b is supported on the upstream side in the paper discharge direction and rotates to a free end portion of a bracket 13 that is rotatably provided in the vertical direction. It is supported freely. The driven roller 9b abuts on the driving roller 9a by its own weight or urging force, and the paper is nipped between the rollers and discharged. When the bound sheet bundle is discharged, the bracket 13 is rotated upward and returned at a predetermined timing. This timing is determined based on the detection signal of the paper discharge sensor SN3.
[0016]
As shown in FIG. 1, when the paper discharge tray 2 is positioned at the paper discharge outlet E2 in order from the top on the paper discharge outlets E1 and E2 side of the apparatus main body, the retraction position of the paper discharge tray 1 (with respect to the paper discharge outlet E1). The retreat position detection sensor SN5 for detecting the sheet receiving position of the paper discharge tray 1), and when the paper discharge tray 1 is set in the paper discharge port E2, the position is detected and the upper surface of the paper discharge tray 2 is detected. Alternatively, a paper surface detection sensor SN6 for detecting the upper surface of the paper on the paper discharge tray 2 and a standby position of the paper discharge tray 2 (when paper is stacked at the position of the stacking surface of the paper discharge tray 2) A standby position detection sensor SN8 for detecting the upper sheet position), a full detection sensor SN9 for detecting the full position of the discharge tray 2, and a lower limit position detection sensor SN7 for detecting the lower limit position of the discharge tray 2. Set up It is.
[0017]
When the paper discharge tray 1 is set at the paper discharge port E2, the paper discharge tray 2 is set not at the lower limit position but at the standby position detected by the standby position detection sensor SN8, and moves little when the paper discharge tray 2 is designated. It can move to the paper discharge outlet E2 at a distance.
Each sensor has a difference in the front and rear position in the paper discharge direction depending on its function. However, in FIGS. 1 and 2, all the sensors are arranged on a straight line so that only the difference in the vertical direction can be seen. it's shown.
[0018]
The paper discharge tray 1 and the paper discharge tray 2 are driven by one vertical driving means described later, and settings for the discharge port E2 are controlled by a control means 100 described later.
[0019]
Next, the configuration of the staple unit 60 will be described.
As shown in FIGS. 1 and 2, the paper guided to the staple route A is stacked on a staple tray (not shown) by the transport roller pair 10 and the paper discharge roller pair 11. In this case, alignment in the vertical direction (paper conveyance direction) is performed by the tapping roller 12 for each sheet, and alignment in the horizontal direction (paper width direction orthogonal to the sheet conveyance direction) is performed by the jogger fence 62. The stapler 61 is driven by a stapling signal from the control means 100 described later between the job breaks, that is, between the last sheet of the sheet bundle and the first sheet of the next sheet bundle, and the binding process is performed.
The sheet bundle subjected to the binding process is immediately sent to the discharge roller pair 9 by the discharge belt 71 having the discharge claw 71a, and the discharge sheet set at the receiving position of the discharge port E2 as shown in FIG. The paper is discharged to the tray 2 (or the paper discharge tray 1).
As shown in FIG. 7, the home position detection sensor SN11 detects the home position of the release claw 71a. The home position detection sensor SN11 is turned on by an operation piece 71b provided on the release belt 71. -Turn off.
[0020]
As shown in FIG. 3, the tapping roller 12 is given a pendulum motion by a tapping solenoid 66 around the fulcrum 12a, and intermittently acts on the paper fed to the staple tray as shown in FIG. It strikes against the end fence 68. At this time, since the discharge roller pair 11 has a brush roller (see FIG. 1), this prevents back flow at the trailing edge of the sheet. The hitting roller 12 rotates counterclockwise.
[0021]
As shown in FIG. 3, the jogger fence 62 is driven via a jogger belt 64 by a jogger motor 63 capable of forward and reverse rotation, and reciprocates in the paper width direction. As shown in FIG. 5, the staple unit 60 is driven via a staple belt 70 by a staple moving motor 69 capable of rotating in the forward and reverse directions, and moves in the width direction of the sheet in order to bind a predetermined position at the end of the sheet.
The staple paper discharge sensor SN4 detects the trailing edge of the paper and immediately issues an ON command to the solenoid 66, and even if the tapping roller 12 is actuated, the trailing edge of the paper discharged to the staple tray (not shown) by the tapping roller 12 is detected. It is abutted against the rear end fence 68 and arranged at a position to be aligned.
[0022]
Next, an operation when the staple mode is selected will be described.
When the staple mode is selected, as shown in FIG. 3, the jogger fence 62 moves from the home position and stands by at a standby position that is 7 mm away from the width of the sheet discharged to the staple tray. When the sheet is conveyed by the conveying roller pair 10 and the trailing end of the sheet passes the staple paper discharge sensor SN4, the jogger fence 62 moves inward by 5 mm from the standby position and stops.
Further, the staple paper discharge sensor SN4 detects when the trailing edge of the paper passes, and the signal is input to the CPU 102 (see FIG. 21). The CPU 102 counts the number of pulses transmitted from the conveying motor that drives the conveying roller pair 10 from the time of receiving this signal, and turns on the hitting solenoid 66 after transmitting a predetermined pulse.
The tapping roller 12 performs a pendulum motion when the tapping solenoid 66 is turned on and off. When the tapping solenoid 66 is on, the tapping roller 12 strikes the paper and returns it to the lower side, and abuts against the rear end fence 68 to align the paper. At this time, every time a sheet stored in the staple tray passes through the entrance sensor SN1 or the staple discharge sensor SN4, the signal is input to the CPU 102, and the number of sheets is counted.
[0023]
After a lapse of a predetermined time after the hit solenoid 66 is turned off, the jogger fence 62 is further moved inward by 2.6 mm by the jogger motor 63 and is temporarily stopped to complete the horizontal alignment. The jogger fence 62 then moves 7.6 mm, returns to the standby position, and waits for the next sheet. This operation is performed up to the last page. After that, it moves again to the inside of 7.6 mm and stops and presses both ends of the sheet bundle to prepare for the stapling operation. Thereafter, the stapler 61 is operated by a staple motor after a predetermined time, and the binding process is performed. At this time, if a plurality of bindings are designated, after the binding process at one place is completed, the staple moving motor 69 is driven, and the stapler 61 is moved to the appropriate position along the rear end of the sheet, so that the second binding is performed. Processing is performed.
[0024]
When the binding process is completed, the discharge motor 72 is driven, and the discharge belt 71 is driven. At this time, the paper discharge motor is also driven, and the paper discharge roller pair 9 starts to rotate to receive the sheet bundle lifted by the discharge claw 71a. At this time, the jogger fence 62 is controlled so that the operation differs depending on the paper size and the number of sheets to be bound.
For example, when the number of sheets to be bound is less than the set number or smaller than the set size, the trailing edge of the sheet bundle is hooked and conveyed by the discharge claw 71a while the sheet bundle is pressed by the jogger fence 62.
[0025]
Then, the jogger fence 62 is retracted 2.6 mm after a predetermined pulse from the detection by the paper presence sensor SN15 (see FIG. 4) or the home position detection sensor SN11 of the discharge claw 71a, and the restraint on the paper by the jogger fence 62 is released. This predetermined pulse is set after the discharge claw 71a collides with the rear end of the paper and passes through the front end of the jogger fence 62.
When the number of sheets to be bound is larger than the set number or larger than the set size, the jogger fence 62 is retracted by 2.6 mm in advance and discharged. In any case, when the sheet bundle passes through the jogger fence 62, the jogger fence 62 moves further outward by 5 mm and returns to the standby position to prepare for the next sheet. It is also possible to adjust the binding force according to the distance of the jogger fence 62 to the paper.
[0026]
Next, the configuration of the paper discharge trays 1 and 2 and its support member (elevating mechanism) will be described.
As shown in FIGS. 8 and 9, the paper discharge tray 1 is provided on a base member 57 supported by a support member 56 composed of a pair of guide rails 30a and 30b described later so as to be movable in the vertical direction.
The paper discharge tray 1 is integrally formed with an end fence 1a for aligning the rear end of the paper. When the paper is loaded on the paper discharge tray 1 with a certain amount or more of the end fence 1a, the end fence 1a is full. A full detection sensor SN12 is provided as a full detection means for detecting (state) (not shown in FIGS. 1 and 2). When detection by the full detection sensor SN12 is performed, control such as prohibition of paper discharge to the paper discharge tray 1 is performed, and the occurrence of poor stacking can be prevented in advance. The fullness here means a stacking amount that does not disturb the stacking state of the sheets when the discharge tray 1 moves up and down with the sheets stacked.
The rear end of the paper in the paper discharge tray 2 is aligned by an end fence 3 that forms the side surface of the apparatus main body. These paper discharge trays 1 and 2 are provided in a stacked state in the vertical direction.
[0027]
The paper discharge tray 1 is attached to a base body 40 fixed between a pair of side plates 39a and 39b located on both sides in the paper discharge direction so as to be slidable in the paper discharge direction via a slide base 50 described later. The side plates 39a and 39b are provided with a rotatable guide roller 44 through a short shaft (not shown). The guide roller 44 is engaged with a pair of U-shaped guide rails 30a and 30b in the vertical direction. It is provided to be movable.
Further, since the guide rollers 44 are positioned by assembling the side plates 39a and 39b and the base body 40, the guide rollers 44 are prevented from coming off from the guide rails 30a and 30b.
A timing belt 35 as an element of the vertical driving means 29 is tensioned around the driving shaft 41a and the driven shaft 41b via a timing pulley 34.
[0028]
On the other hand, like the paper discharge tray 1, the paper discharge tray 2 is attached to a base (not shown) fixed between the side plates 42a and 42b. The side plates 42a and 42b are provided with a rotatable guide roller 44 via a short shaft (not shown). The guide roller 44 is engaged with a pair of U-shaped guide rails 30a and 30b so as to be movable. Is provided. That is, the paper discharge tray 1 and the paper discharge tray 2 share a pair of guide rails 30a and 30b. Further, since the guide roller 44 is positioned by assembling the side plates 42a and 42b and the base, the guide roller 44 is prevented from coming off from the guide rails 30a and 30b.
[0029]
As shown in FIG. 10, the paper discharge tray 1 and the paper discharge tray 2 move up and down by driving the drive shaft 41 a by the vertical driving means 29. In FIG. 10, the paper discharge tray 1 is omitted.
The power generated by the up-and-down motor 31 that can move forward and backward as a drive source for moving the discharge tray 1 and the discharge tray 2 in the vertical direction is transmitted via the worm gear 30 to the final gear of the gear train fixed to the drive shaft 41a. It has come to be. Since the worm gear 30 is provided midway, the discharge trays 1 and 2 can be held at a fixed position, and an accidental drop accident of the discharge trays 1 and 2 can be prevented.
[0030]
A shielding plate (not shown) is integrally formed on the side plate 42 of the paper discharge tray 2, and the fullness detection sensor SN9 and the lower limit position detection sensor SN7 are turned on / off by the shielding plate. These sensors are photosensors that are turned on when blocked by a shielding plate.
The standby position detection sensor SN8 has a configuration in which the detection piece protrudes from the surface of the end fence 3 with a biasing force, and is turned on when the detection piece abuts against the paper on the paper discharge tray 2 or the paper on the paper discharge tray 2. • It is turned off (the full detection sensor SN9 is omitted in FIGS. 8 and 9).
The paper surface detection sensor SN6 has the same configuration as the standby position detection sensor SN8. In FIG. 4, the driven roller 9b of the paper discharge roller pair 9 is omitted. In FIG. 4, reference numeral 17 denotes a sponge return roller that comes into contact with the paper discharged from the paper discharge port E <b> 2 and abuts the rear end of the paper against the end fence 3.
[0031]
Next, the slide configuration of the paper discharge tray 1 in the paper discharge direction will be described in detail with reference to FIGS.
As shown in FIGS. 8 and 9, the guide rails 30 a and 30 b have interference between the drive roller 9 a of the paper discharge roller pair 9 protruding from the moving surface of the paper discharge tray 1 in the paper discharge direction and the paper discharge tray 1. In order to avoid this, a cam 81 for sliding the paper discharge tray 1 in the paper discharge direction is provided. The length of the cam 81 in the vertical direction extends from the vicinity below the paper discharge roller pair 9 to the paper discharge roller pair 7.
The thickness of the cam 81 in the paper discharge direction is three stages: a thick portion 81a that can avoid interference with the paper discharge roller pair 9, an inclined portion 81b, and a thin portion 81c located below the paper discharge roller pair 9. ing.
A guide roller 80 that rolls on the cam surface of the cam 81 (the front surface of the cam 81 in the sheet discharge direction) is provided on the back surface of the end fence 1 a of the discharge tray 1.
[0032]
As shown in FIG.11 and FIG.12, the slide rail 53 is being fixed to the inner surface of the side plates 39a and 39b, respectively. Two shafts 51 having guide rollers 52 guided by the slide rails 53 are provided at both ends between the slide rails 53, and the slide base 50 is supported between the shafts 51 (in this case, fixed). Has been. The paper discharge tray 1 is fixed to the slide base 50.
One ends of springs 54 as elastic members are engaged with both ends of the slide base 50 in the sheet width direction, and the other ends of the springs 54 are raised at the rear end of the base body 40 in the sheet discharge direction. It is latched by the spring latching piece 40a. With this configuration, the paper discharge tray 1 is constantly pressed against the cam 81 by the biasing force of the spring 54, and the guide roller 80 is in contact with the cam surface.
The side plates 39a and 39b, the base body 40, the slide base 50, the shaft 51, the slide rail 53, the spring 54, and the like constitute a base member 57 that supports the paper discharge tray 1.
[0033]
FIG. 8 shows a state in which the paper discharge tray 1 is set at the receiving position of the paper discharge port E1, and the paper discharge tray 2 is set at the receiving position of the paper discharge port E2. In this case, since the guide roller 80 of the paper discharge tray 1 is located at the thick portion 81a of the cam 81, as shown in FIG. 11, the end fence 1a of the paper discharge tray 1 and the pair of paper discharge rollers in the paper discharge direction. There is a slight gap between 9 and 9.
From this state, as shown in FIG. 9, when the paper discharge tray 2 is placed in a standby position and the paper discharge tray 1 is set at the receiving position of the paper discharge port E2, the paper discharge tray 1 moves up the paper discharge port E2. , The paper discharge tray 1 does not interfere with the paper discharge roller pair 9 because the guide roller 80 passes through the paper discharge port E2 with the guide roller 80 positioned at the thick portion 81a of the cam 81. To do.
Thereafter, the guide roller 80 reaches from the thick part 81a to the thin part 81c via the inclined part 81b. When the guide roller 80 enters the inclined portion 81b, the paper discharge tray 1 starts to slide toward the cam 81 due to the biasing force of the spring 54, and is finally positioned at a position where paper can be received from the paper discharge port E2. The slide of the discharge tray 1 is not tilted while maintaining the posture by the horizontal movement of the slide base 50, in other words.
[0034]
At this receiving position, as shown in FIG. 12, the end fence 1a of the paper discharge tray 1 and the drive roller 9a of the paper discharge roller pair 9 overlap. Strictly, although not shown, the end fence 1a is formed with a notch recessed portion that is notched in the vertical direction so as to avoid interference with the driving roller 9a. Only overlaps the driving roller 9a in the vertical direction. As a result, the trailing edge of the sheet discharged from the sheet discharge outlet E2 is prevented from entering between the drive roller 9a and the end fence 1a to cause a stacking failure. This overlap configuration also functions in the same manner for the paper discharge roller pair 7 at the paper discharge port E1.
The paper surface detection sensor SN6 for setting the paper discharge tray 1 to the receiving position of the paper discharge port E2 is turned on / off at the lower end of the notch recess when no paper is loaded on the paper discharge tray 1. . In addition, although not shown, in order to avoid interference between the return roller 17 and the end fence 1a of the paper discharge tray 1, a similar notch recess is formed in the end fence 1a.
[0035]
According to the cam configuration, the discharge tray 1 can be slid in the sheet discharge direction by using the vertical movement force of the discharge tray 1 to avoid interference with the discharge roller pair 9, so that interference can be avoided. There is no need to provide a dedicated drive source, and there is an advantage that cost reduction can be realized.
[0036]
As shown in FIGS. 13 and 14, a shift motor 46, a crank gear 47, and the like are disposed on the back side of the end fence 3 so that the end fence 3 can be shifted. A member 80 having a long hole extending vertically is fixed to the back surface of the end fence 3, and a pin 86 that is eccentrically fixed to the crank gear 47 is engaged with the long hole. The rotation of the shift motor 46 is transmitted to the worm gear 82 by the belt 84, and the crank gear 47 engaged therewith rotates.
This shift movement is monitored by the shift sensor SN14, and the stop position is determined. The end fence 3 and the discharge tray 2 are fitted in a comb shape that allows the discharge tray 2 to move up and down, and the discharge tray 2 follows the movement of the end fence 3.
With this configuration, a sorting stack in the paper discharge tray 2 is possible.
[0037]
In this embodiment, the offset stack is realized by the shift operation of the paper discharge trays 1 and 2 itself, but it is also possible to shift the paper while it is being transported by, for example, shifting the transport roller or the paper discharge roller. A method using a jogger fence of the staple unit 60 is also conceivable for the offset stack in the paper discharge tray 2. Moreover, it is also possible to combine these methods.
[0038]
As shown in FIG. 21, the control means 100 is a microcomputer having a CPU 102, an I / O interface 104, and the like, each switch (SW) of a control panel of the apparatus main body (not shown) of the copying machine G, and a paper surface detection sensor. Signals from sensors such as SN 6 are input to the CPU 102 via the I / O interface 104. Based on the input signal, the CPU 102 includes a vertical motor 31, a solenoid 20 a, a solenoid 21 a, a tapping solenoid 66, a transport motor that drives each transport roller pair, a paper discharge motor that drives each paper discharge roller pair, and a stapler 61. The driving of a stapling motor for driving, a discharging motor 72 for driving the discharging belt 71, a staple moving motor 69 for moving the stapler 61, a jogger motor 63 for driving the jogger fence 11, and the like are controlled.
The pulse signal of the conveying motor that drives the conveying roller pair 10 is input to the CPU 102 and counted, and the hitting solenoid 66 is controlled according to this count.
The matching control means is composed of the CPU 102 and various operation programs that operate the CPU 102.
[0039]
In the above configuration, first, an operation when the non-staple mode in which the binding process is not performed is selected will be described.
(When discharging from the discharge roller pair 7 to the discharge tray 1)
The copied paper is received by the entrance roller pair 5, transported by the transport roller pair 6, discharged by the paper discharge roller pair 7, and stacked on the paper discharge tray 1. At this time, the paper discharge roller pair 7 is decelerated when the paper discharge sensor SN2 detects the trailing edge of the paper, thereby improving the stackability.
[0040]
(When discharging from the discharge roller pair 9 to the discharge tray 2)
The copied paper is received by the entrance roller pair 5, transported by the transport roller pair 8, discharged by the paper discharge roller pair 9, and stacked on the paper discharge tray 2. At this time, the paper discharge roller pair 9 is decelerated when the paper discharge sensor SN3 detects the trailing edge of the paper, thereby improving the stackability.
Further, when the copied paper is sequentially discharged and the upper surface is detected by the paper surface detection sensor SN6, the vertical motor 31 is driven and the paper discharge tray 2 is lowered so that the paper surface height is always at an appropriate height. Kept. In the sort and stack modes, the shift motor 46 is driven by the partition signal output from the control panel of the copying machine G to shift the discharge tray 2 and sort until the job is completed.
[0041]
Next, the driving force switching means in the paper discharge tray 1 will be described with reference to FIGS. 15 to 18 (omitted in FIGS. 1, 2, 8, 9 and the like).
The driving force switching means 300 is provided with a timing pulley 303 that meshes with the timing belt 35 and a timing roller 35 that is opposed to the timing pulley 303 and sandwiches the timing belt 35 to prevent the timing belt 35 and the timing pulley 303 from being disengaged. 301, a latch 304 that restricts the rotation of the timing pulley 303, a rotation restricting lever 307 that engages with the latch 304, a spring 306 that urges the rotation restricting lever 307 to engage with the latch 304, and a rotation restricting member. A solenoid 305 for engaging / disengaging the lever 307 and the latch 304 is provided.
[0042]
  The holding roller 301 is rotatably supported outside the side plate 39. As shown in FIG. 17, the latch 304 is fixed to the outside of the side plate 39 on a shaft 302 that is rotatably supported between the side plates 39.
  As shown in FIG. 18, the rotation restricting lever 307 includes a shaft portion 307 a inserted through a shaft supported between the side plates 39, a long hole 307 b engaged with the rod pin 305 a of the solenoid 305, and an engagement with the latch 304. A claw portion 307c is provided.
  The latch 304 has four engagement recesses for the engagement claw portion 307c.304ahave. Engaging recess304aIndicates that the latch 304 is kept engaged with the engaging claw 307c in the rotation direction (arrow A direction) when the discharge tray 1 is lowered, and the latch 304 is rotated when the discharge tray 1 is raised. In the direction of arrow B, it has a shape for releasing the engagement.
[0043]
  In the driving force transmission operation of the driving force switching means 300, the solenoid 305 is turned off, the rotation restricting lever 307 is rotated by the biasing force of the spring 306, and the engaging claw portion 307c is engaged with the engaging recess of the latch 304 as shown by the solid line.304aEngage with. As a result, the rotation of the timing pulley 303 is restricted, and the paper discharge tray 1 moves up and down in synchronization with the movement of the timing belt 35.
  As described above, the engagement is disengaged in the upward direction of the discharge tray 1. This is because when the paper discharge trays collide with each other for some reason, the force is released to protect the machine and to ensure safety when an operator's hand is sandwiched between the paper discharge trays.
  In the driving force shut-off operation of the driving force switching means 300, the solenoid 305 is turned on, and the engagement of the rotation restricting lever 307 and the latch 304 is released, as shown by the one-dot chain line. As a result, the timing pulley 303 is in a free state, and only a force in the dropping direction is applied regardless of the movement of the timing belt 35. The driving force switching means in the paper discharge tray 2 has the same configuration.
[0044]
In the driving force blocking operation of the driving force switching means, the paper discharge tray 1 falls, but a locking means is provided to prevent this and stop at that position. The locking means corresponding to the paper discharge tray 1 will be described based on FIGS. 19 and 20 (omitted in FIGS. 1, 2, 8, 9 and the like).
As shown in FIG. 19, the lock means 308 includes a rack 312 extending in the vertical direction, a movable stopper 309 that engages with the rack 312, and a spring 311 that biases the movable stopper 309 to engage with the rack 312. In addition, a solenoid 310 for engaging and releasing the movable stopper 309 and the rack 312 is provided. In FIG. 8 and FIG. 9, the tooth portion of the rack 312 is omitted.
As shown in FIG. 20, the movable stopper 309 includes a shaft portion 309 a inserted through a shaft 313 supported between the side plates 39, a long hole 309 b engaged with the rod pin 310 a of the solenoid 310, and a tooth groove of the rack 312. Engaging claw portion 309c.
[0045]
As shown in FIG. 19, the shape of the tooth portion of the rack 312 is provided with an inclined portion so that the lock function acts only in the dropping direction, and when a force acts in the direction of raising the discharge tray 1. The engaging claw portion 309c of the movable stopper 309 can move over the tooth portion.
This is because, like the driving force switching means 301, when the discharge trays collide with each other for some reason, the force is released to protect the machine, and when the operator's hand is sandwiched between the discharge trays. This is to ensure safety.
[0046]
In the stopping operation of the locking means 308, the solenoid 310 is turned off, the movable stopper 309 is rotated by the urging force of the spring 311, and the engaging claw portion 309c is engaged with the rack 312 as shown by the solid line. Thus, the position of the paper discharge tray 1 is fixed even when the timing pulley 303 is free.
In the stop releasing operation of the lock unit 308, the solenoid 310 is turned on, and the engagement between the movable stopper 309 and the rack 312 is released as shown by a one-dot chain line. The driving force switching means in the paper discharge tray 2 has the same configuration. However, the rack 312 is a common member.
[0047]
  Next, the vertical movement of the paper discharge trays 1 and 2 will be described.
(When the paper output tray is stopped)
  The movable stopper 309 engages with the rack 312 to restrict the movement of the discharge tray in the dropping direction. At this time, the rotation restricting lever 307 isLatch 304Even when the timing belt 35 is disengaged and the timing belt 35 moves, the timing pulley 303 only rotates freely. Accordingly, the paper discharge tray is stopped at that position.
(When the output tray starts to rise)
  The rotation restricting lever 307Latch 304, And the rotation of the timing pulley 303 with respect to the timing belt 35 in the tray dropping direction is restricted. At substantially the same time as this operation, the engagement of the movable stopper 309 with the rack 312 is released. Accordingly, the paper discharge tray follows the timing belt 35 and moves in the upward direction.
(When the output tray starts to descend)
  The timing belt 35 slightly moves in the direction of once raising the paper discharge tray. This is because, in the configuration, the movable stopper 309 cannot move to the release position at the stop position, and moves to a position where the engagement claw portion 309c of the movable stopper 309 and the rack 312 can be detached. Almost simultaneously with this operation, the movable stopper 309 rotates to the release position, and the stop of the paper discharge tray is released.
  At this time, the rotation restricting lever 307 is engaged with the latch 304, and the rotation of the timing pulley 303 with respect to the timing belt 35 in the tray dropping direction is restricted. Accordingly, the paper discharge tray follows the timing belt 35 and moves in the downward direction.
[0048]
In the present embodiment, as shown in FIG. 15, a distance measuring sensor SN16 serving as a distance measuring means for measuring the distance between the paper discharge trays is provided in the lower part of the unit of the paper discharge tray 1. The distance measuring sensor SN16 is attached so as to measure the distance of the paper discharge tray 2 to the paper stacking surface. When the paper is not loaded, the paper discharge tray 2 itself is used. The distance to the upper surface is measured.
The control means 100 controls the vertical movement / stop of the paper discharge trays 1 and 2 based on the measurement information of the distance measuring sensor SN16. When the distance between the paper discharge trays 1 and 2 is equal to or less than a predetermined value, the control unit 100 controls the paper discharge tray 2 that is the object of distance measurement to move up and down. That is, the paper discharge tray 1 and the paper discharge tray 2 are moved in synchronization. When the value exceeds a certain value, the paper discharge tray 2 is not moved so as not to make unnecessary movement.
[0049]
The constant value (predetermined distance) in the present embodiment is a set value that gives priority to safety and is such that the interval between the paper discharge tray 1 and the paper discharge tray 2 is at least 50 mm.
The actual operation will be described based on the flowcharts of FIGS. First, the operation when the discharge tray 1 is lowered will be described based on the flowchart of FIG. It is checked whether or not the lowering of the discharge tray 1 has been started (S1). If it has started, the output signal of the distance measuring sensor SN16 is read (S2).
Next, it is checked whether or not the detection distance to the paper discharge tray 2 is 50 mm or more (S3). If it is 50 mm or less, the lowering of the paper discharge tray 1 is temporarily stopped (S4). At this time, the discharge tray 2 slightly rises to a position where the movable stopper 309 and the rack 312 are disengaged, and then the movable stopper 309 is released. Thereafter, the paper discharge tray 1 and the paper discharge tray 2 are lowered synchronously (S5).
Next, it is checked whether or not the paper discharge tray 1 has reached the target movement position (S6). If it has reached, the movement of the paper discharge tray 1 is stopped (S7).
[0050]
Next, the operation when the discharge tray 2 is raised will be described based on the flowchart of FIG. It is checked whether or not the raising of the discharge tray 2 has started (S1), and if it has started, the output signal of the distance measuring sensor SN16 is read (S2).
Next, it is checked whether or not the detection distance to the paper discharge tray 1 is 50 mm or more (S3), and if it is 50 mm or less, the elevation of the paper discharge tray 2 is temporarily stopped (S4). At this time, the discharge tray 1 is slightly raised to a position where the movable stopper 309 and the rack 312 are disengaged, and then the movable stopper 309 is released. Thereafter, the paper discharge tray 2 and the paper discharge tray 1 rise in synchronization (S5).
Next, it is checked whether or not the paper discharge tray 2 has reached the target movement position (S6). If it has reached, the movement of the paper discharge tray 2 is stopped (S7).
[0051]
Next, control operations other than those described above for the discharge trays 1 and 2 by the control means 100 will be described.
First, the initial operation (homing operation) of the paper discharge trays 1 and 2 will be described. As shown in FIG. 1, the home position of the discharge tray 1 is the position where the rear end of the base member 57 is detected by the retracted position detection sensor SN5, and the discharge tray 2 is the paper surface detection sensor SN6. Is the position at which the upper end of the stacking surface or the top surface of the stacked sheets is detected (the same applies to other embodiments below).
This initial operation will be described with reference to the flowchart of FIG. In the following flowcharts, the paper discharge tray 1 is simply abbreviated as tray 1 and the paper discharge tray 2 is abbreviated as tray 2.
First, in order to set the paper discharge tray 1 at the receiving position of the paper discharge outlet E1, the control means 100 checks the retreat position detection sensor SN5 (S1), and if it is off, raises the paper discharge tray 1 (S2). Subsequently, the retreat position detection sensor SN5 is checked (S3), and when it is turned on, the paper discharge tray 1 is stopped (S4). If the retract position detection sensor SN5 is on in S1, the process proceeds to S5.
[0052]
Next, in order to set the paper discharge tray 2 at the receiving position of the paper discharge outlet E2, the control means 100 checks the paper surface detection sensor SN6 (S5), and if it is off, the paper discharge tray 2 is once raised (S6). . Subsequently, the paper surface detection sensor SN6 is checked (S7), and when it is turned on, the paper discharge tray 2 is stopped (S8). Next, after lowering the paper discharge tray 2 (S9), the paper surface detection sensor SN6 is checked (S10). When it is turned off, the paper discharge tray 2 is stopped (S11), and the position flag of the paper discharge tray 1 is set to 0. Is set (S12).
In S5, when the paper surface detection sensor SN6 is on, the discharge tray 2 is lowered (S13), and the process proceeds to S10.
[0053]
Next, a case where the position flag of the paper discharge tray 1 is 0, the paper discharge tray 1 is set at the receiving position of the paper discharge port E2, and the paper discharge tray 2 is set in the standby state will be described with reference to the flowchart of FIG.
First, the position flag of the paper discharge tray 1 is checked (S14). If the position flag is 0, it is determined that the paper discharge tray 1 is at the receiving position of the paper discharge port E1, and the following operation is performed. First, the discharge tray 2 is lowered to set the discharge tray 2 in a standby state (S15), and then whether or not the standby position detection sensor SN8 has been turned off from on, that is, turned on at the lower end of the discharge tray 2. Then, it is checked whether or not the upper end or the upper end of the paper on the paper discharge tray 2 has passed and turned off (S16), and when it turns from on to off, the paper discharge tray 2 is stopped (S17).
[0054]
Next, in order to set the paper discharge tray 1 to the receiving position of the paper discharge port E2, the paper discharge tray 1 is lowered (S18), and whether or not the paper surface detection sensor SN6 has been turned off from on, that is, the paper discharge tray 1 It is turned on at the lower end, and it is checked whether or not the upper end of the end fence 1a (strictly, the lower end of the cut-out recess) is turned off (S19), and when it is turned off from on, the paper discharge tray 1 is stopped (S20). ). Then, 1 is set to the position flag of the paper discharge tray 1 (S21).
In the present embodiment, as described above, the paper surface detection sensor SN6 as detection means for positioning the paper discharge tray 2 at the reception position of the paper discharge outlet E2 is used, and the paper discharge tray 1 is set at the reception position of the paper discharge outlet E2. Shared as a detection means for positioning.
[0055]
Next, a case where the position flag of the paper discharge tray 1 is 1 and the paper discharge tray 1 is set to the receiving position of the paper discharge port E2 or the paper discharge tray 2 is set to the standby state will be described with reference to the flowchart of FIG. .
First, the position flag of the discharge tray 1 is checked (S22). If the position flag is 1, the discharge tray 1 is raised to confirm that the discharge tray 1 is at the receiving position of the discharge port E2. (S23), the paper surface detection sensor SN6 is checked (S24). When the paper surface detection sensor SN6 is turned on, the paper discharge tray 1 is stopped (S25), and then the paper discharge tray 1 is lowered (S26). Subsequently, the paper surface detection sensor SN6 is checked (S27), and when it is turned off, the paper discharge tray 1 is stopped (S28), and the paper discharge tray 1 is set at the receiving position of the paper discharge port E2.
[0056]
Next, in order to set the paper discharge tray 2 to the standby state, the paper discharge tray 2 is raised (S29), and the standby position detection sensor SN8 is checked (S30). When it is turned on, the paper discharge tray 2 is stopped (S31), and then the paper discharge tray 2 is lowered (S32). Next, the standby position detection sensor SN8 is checked (S33), and when it is turned off, the paper discharge tray 2 is stopped (S34). Then, the position flag of the paper discharge tray 1 is set to 1 (S35).
That is, when the position flag is 1, the discharge tray 1 is raised and lowered and reset by the paper surface detection sensor SN6, and the discharge tray 2 is raised and lowered and reset by the standby position detection sensor SN8.
[0057]
Next, the operation when the position flag of the discharge tray 1 is 0 and the discharge tray 1 is reset to the receiving position of the discharge outlet E1 or the discharge tray 2 is reset to the receiving position of the discharge outlet E2 is shown in FIG. It demonstrates based on the flowchart of these.
First, the position flag of the paper discharge tray 1 is checked (S36). If it is 0, it is determined that the paper discharge tray 1 is at the receiving position of the paper discharge port E1, and the following operation is performed. First, the paper surface detection sensor SN6 is checked to set the paper discharge tray 2 at the receiving position of the paper discharge port E2 (S37), and if it is off, the paper discharge tray 2 is temporarily raised (S38). Subsequently, the paper surface detection sensor SN6 is checked (S39). If it is turned on, the paper discharge tray 2 is stopped (S40), and then the paper discharge tray 2 is lowered (S41). Further, the paper surface detection sensor SN6 is checked (S42), and when it is turned off, the paper discharge tray 2 is stopped (S43).
[0058]
Next, the retreat position detection sensor SN5 is checked (S44), and if it is off, the discharge tray 1 is raised (S45). Subsequently, the retreat position detection sensor SN5 is checked (S46), and when it is turned on, the paper discharge tray 1 is stopped (S47). That is, the paper discharge tray 1 is reset by the retreat position detection sensor SN5. Then, 0 is set in the position flag of the paper discharge tray 1 (S48).
If the paper surface detection sensor SN6 is on in S2, the paper discharge tray 2 is lowered (S49), and the process proceeds to S42.
[0059]
Next, the flowchart of FIG. 28 shows a case where the position flag of the paper discharge tray 1 is 1, and the paper discharge tray 1 is set at the reception position of the paper discharge outlet E1 or the paper discharge tray 2 is set at the reception position of the paper discharge outlet E2. Based on
The position flag of the paper discharge tray 1 is checked (S50). If the position flag is 1, it is determined that the paper discharge tray 1 is at the receiving position of the paper discharge port E2, and the following operation is performed.
First, in order to set the paper discharge tray 1 at the receiving position of the paper discharge port E1, the paper discharge tray 1 is raised (S51), the retreat position detection sensor SN5 is checked (S52), and when it is turned on, the paper discharge tray 1 is stopped. (S53).
Next, in order to set the paper discharge tray 2 to the receiving position of the paper discharge port E2, the paper discharge tray 2 is raised (S54), and the paper surface detection sensor SN6 is checked (S55). Stop (S56). Next, the paper discharge tray 2 is lowered (S57), and the paper surface detection sensor SN6 is checked (S58). When it is turned off, the paper discharge tray 2 is stopped (S59), and the position flag of the paper discharge tray 1 is set to 0 (S60).
[0060]
In an actual copying operation, a post-processing mode and a paper discharge destination are determined on an operation unit of an image forming apparatus such as a copying machine or a printer driver, and a paper discharge tray is switched based on the information.
In the state shown in FIG. 1 (discharge tray default state), the discharge tray is switched only when discharging to the discharge tray 1 in the staple mode. That is, the paper discharge tray 1 is set at the receiving position of the paper discharge port E2.
When the job is completed in the state shown in FIG. 2, the homing operation of the paper discharge trays 1 and 2 is appropriately performed based on the determination of the control unit of the image forming apparatus G.
[0061]
【The invention's effect】
  The present inventionAccording to1A plurality of paper discharge trays can be moved up and down with one drive source and can be stopped individually at an arbitrary position, so that compactness and cost reduction can be realized.
[0062]
  The present inventionAccording to, ExhaustProblems caused by falling paper trays can be prevented.
[0063]
  The present inventionAccording to, ExhaustAccidents such as paper tray collision and damage can be prevented.
[0064]
  The present inventionAccording to,NothingIt is possible to prevent accidents such as the paper discharge tray colliding and being damaged while minimizing unnecessary operations.
[0065]
  The present inventionAccording to, CheapIntegrity can be improved.
[Brief description of the drawings]
FIG. 1 is a schematic front view of a sheet post-processing apparatus as a sheet stacking apparatus according to an embodiment of the present invention, and shows a state in which a lower discharge tray is set at a receiving position of a discharge outlet E2.
FIG. 2 is a schematic front view of a sheet post-processing apparatus in a state where an upper discharge tray is set at a receiving position of a discharge outlet E2.
FIG. 3 is a perspective view of a staple unit.
FIG. 4 is a schematic front view showing a hitting operation in the staple unit.
FIG. 5 is a perspective view of a staple unit.
FIG. 6 is a perspective view showing a discharging operation of the staple unit.
FIG. 7 is a perspective view showing a configuration for detecting the home position of the discharge belt.
FIG. 8 is a schematic front view of a lifting mechanism of a paper discharge tray in a state where a lower paper discharge tray is set at a receiving position of a paper discharge port E2.
FIG. 9 is a schematic front view of the lifting mechanism of the discharge tray in a state where the upper discharge tray is set at the receiving position of the discharge port E2.
FIG. 10 is a perspective view illustrating a drive mechanism of a paper discharge tray.
FIGS. 11A and 11B are diagrams illustrating a state in which the upper discharge tray is movable through the discharge outlet, where FIG. 11A is a schematic plan view, and FIG. 11B is a schematic side view.
FIG. 12 is a schematic plan view of a state in which the upper paper discharge tray is set at a receiving position of a paper discharge port.
FIG. 13 is a perspective view illustrating a shift configuration of a lower discharge tray.
FIG. 14 is a perspective view illustrating a shift configuration of a lower discharge tray.
FIG. 15 is a schematic front view showing driving force switching means and locking means.
FIG. 16 is a schematic front view showing the positional relationship between the timing pulley and the holding roller in the driving force switching means.
FIG. 17 is a perspective view showing a timing pulley and a latch in the driving force switching means.
FIG. 18 is a schematic front view showing an engagement configuration of a latch and a rotation restricting lever in the driving force switching means.
FIG. 19 is a schematic front view showing the engagement relationship between the movable stopper and the rack in the locking means.
FIG. 20 is a perspective view of a movable stopper in the locking means.
FIG. 21 is a control block diagram.
FIG. 22 is a flowchart illustrating a control operation when the upper discharge tray is lowered.
FIG. 23 is a flowchart showing a control operation when the lower discharge tray is raised.
FIG. 24 is a flowchart showing an initial operation of the paper discharge tray.
FIG. 25 is a flowchart showing an operation for setting the upper discharge tray at the receiving position of the discharge outlet E2.
FIG. 26 is a flowchart showing an operation of resetting the upper discharge tray located at the discharge outlet E2 to the discharge outlet E2.
FIG. 27 is a flowchart showing an operation of resetting the upper discharge tray set at the receiving position of the discharge outlet E1 to the receiving position of the discharge outlet.
FIG. 28 is a flowchart showing an operation for setting the upper discharge tray set at the receiving position of the discharge port E2 to the receiving position of the discharge port E1.
[Explanation of symbols]
1 Output tray
2 Output tray
29 Vertical drive means
56 Support members
100 Control means
300 Driving force switching means
308 Locking means
SN16 Ranging sensor as ranging means

Claims (7)

A plurality of paper discharge trays for discharging sheets, a support member that supports the paper discharge tray so as to be vertically movable over the entire moving distance, and a vertical direction for moving the paper discharge tray in the vertical direction in the sheet stacking apparatus having a driving means,
One of the vertical driving means is provided so as to be shared by the plurality of paper discharge trays, and the driving force from the vertical driving means can be arbitrarily transmitted to and cut off from each of the paper discharge trays. has a force switching means, and a locking means which can stop and unpause at any position,
The vertical driving unit includes a timing belt for moving the plurality of paper discharge trays in the vertical direction, and the driving force switching unit includes a timing pulley that simultaneously meshes a plurality of teeth with the timing belt. When the driving force is transmitted / blocked through the timing belt by restricting / releasing the rotation of the pulley, and the driving force is cut off by the driving force switching means, the corresponding discharge tray is moved by the locking means. A paper stacking device which stops at that position . The paper stacking apparatus according to claim 1, wherein
The drive force switching means has a holding roller at a position facing the timing pulley across the timing belt to prevent disengagement between the timing belt and the timing pulley. apparatus. The paper stacking apparatus according to claim 1 or 2 ,
And characterized by comprising a distance measuring means for measuring a distance between said discharge tray, and control means for controlling the vertical movement and stopping of each discharge tray based on the measurement information of the distance measuring means Paper loading device to do. The paper stacking apparatus according to claim 3.
The sheet stacking apparatus according to claim 1, wherein when the distance between the discharge trays is equal to or less than a predetermined value, the control unit controls the discharge tray to be measured to be moved up and down. The paper stacking apparatus according to any one of claims 1 to 4,
The paper stacking apparatus according to claim 1, wherein the driving force switching unit is configured to permit the upward movement of the paper discharge tray in a driving force transmission state. The paper stacking apparatus according to any one of claims 1 to 5,
The paper stacking apparatus according to claim 1, wherein the lock unit is configured to permit the upward movement of the paper discharge tray in a stopped state. An image forming apparatus comprising the paper stacking apparatus according to claim 1.

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