JP2000169031A - Sheet loading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the friction force of sheets for smooth conveyance when conveying the sheets from a processing tray by providing a sheet support member movable between a support position where the coupling between the sheets and a conveying means is reduced and a retreat position retreated from the support position and a driving means moving the sheet support member. SOLUTION: A variable means 35 changing the frictional force between a discharge roller 34 and sheets is provided with a sheet support member, e.g., a curved guide plate 45, which supports the sheets loaded on a processing tray 9 and is movable between a support position where the coupling between the sheets and a discharge roller 34 serving as a conveying means is reduced and a retreat position retreated from the support position. When a plate spring 42 is brought into contact with a coupling section 45B by the descent of a rotary member 37 rotating around a shaft 37A supporting a lift roller 36, the guide plate 45 is moved to the retreat position. A driving means retreating the guide plate 45 to the retreat position when the sheets are conveyed from the processing tray 9 is provided with the plate spring 42 and the coupling section 45B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of temporarily stacking an image-formed sheet discharged from an image forming apparatus such as a copying machine or a printer on a stacking unit, post-processing the sheet with a stapler or the like, and stacking the sheet. The present invention relates to a sheet processing apparatus such as a finisher that conveys a sheet from a unit to an accumulation unit.

[0002]

2. Description of the Related Art Conventionally, a finisher for stapling a sheet supplied from an image forming apparatus with a stapler has a discharging means for discharging the sheet supplied from the image forming apparatus, and an inclination for stacking the sheet discharged from the discharging means. A processing tray, a discharge roller contacting the lowermost surface of the sheet stacked on the processing tray, an elevating roller contacting the uppermost surface of the sheet, and contacting / separating means for moving the elevating roller closer to and away from the uppermost surface of the sheet. And a stapler that binds sheets stacked on the processing tray, and discharges the sheets stapled by the stapler from the processing tray to the stacking tray with a discharge roller and an elevating roller sandwiching the sheet.

In such a finisher, when the sheets discharged from the discharge means are stacked on the processing tray, the leading edge of the sheet abuts against a discharge roller, or the stacked sheets slide down to the stapler side according to the inclination of the processing tray. The lower surface of the sheet may come into contact with the discharge roller, and the sheet may not slide down smoothly on the processing tray. In particular, when the first sheet is discharged onto the processing tray, there is a possibility that the first sheet will not slide down smoothly, and the alignment may not be performed properly, which may cause a binding failure of the sheet bundle.

In Japanese Patent Application Laid-Open No. Hei 10-279164, a projection is provided on both sides of the discharge roller of the processing tray so as to protrude upward from the upper end position of the discharge roller and elastically bend downward by the weight of the sheet. When stacking sheets on top, the stacking of the sheets is smooth because the protrusions protrude from the discharge rollers, but when the staple-bound sheet bundle is transported onto the stacking tray, the discharge rollers and the lifting rollers When the sheet bundle is sandwiched between (1) and (2), the weight of the sheet bundle causes the protrusion to elastically bend and retreat downward, so that the gripping force between the discharge roller and the elevating roller is not affected.

[0005]

However, even if the protrusion is elastically retracted from a position protruding from the discharge roller due to the weight of the sheet bundle, frictional force is exerted on the lower surface of the sheet by the elastic force of the protrusion. When the sheet is conveyed from the processing tray, the protrusion acts as a load on the sheet, and the sheet being discharged may be skewed, or the trailing end of the discharged sheet may remain in contact with the protrusion. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet processing apparatus capable of reducing the frictional force on the lower surface side of a sheet and conveying the sheet smoothly when the sheet is conveyed from a stacking means such as a processing tray.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, there is provided a stacking means for stacking at least one supplied sheet, and a sheet conveyed in contact with the sheet stacked on the stacking means. A sheet stacking apparatus comprising: a support position for supporting at least a part of a sheet on the stacking device to reduce engagement between the sheet and the transfer device; and a retreat position retracted from the support position. And a driving means for moving the sheet support member between the support position and the retracted position.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sheet processing apparatus according to the present invention will be described below with reference to the accompanying drawings.

<Structure> FIG. 1 shows the overall structure of a sheet processing apparatus 1 according to the present invention. The sheet processing apparatus 1 is connected to a discharge port of an image forming apparatus 4 such as a copying machine or a printer while being supported by a support member 3 attached to a frame 2. The sheet processing apparatus 1 is supplied with an auxiliary stacking unit 7 for directly stacking the sheets supplied from the image forming apparatus 4 via the transport paths 5 and 6, and supplied from the image forming apparatus 4 via the transport paths 5 and 8. The processing unit 10 supports the trailing end of the stacked sheets with the processing tray 9 (stacking unit) and performs post-processing such as stapling the sheet bundle, and supports the leading end side of the sheets stacked on the processing tray 9. In addition, a stacking unit 11 for stacking the sheets discharged from the processing tray 9 after the processing such as stapling or the like is provided.

As shown in FIG. 2, the conveying path 5 has guide plates 12 and 13 opposed to each other with an interval allowing passage of sheets.
Is formed by An entrance sensor 1 for detecting a sheet supplied from the image forming apparatus 4 is provided in the transport path 5.
4 and transport rollers 15 and 16 for transporting the sheet. The entrance sensor 14 includes a lever 14B that rotates around a shaft 14A, and a detection element 14C that detects the rotation of the lever 14B.

The transport path 6 is formed by guide plates 13, 17, and 30 which are opposed to each other with an interval through which sheets can pass. Further, discharge rollers 18 and 19 for discharging a sheet and a sensor 20 for detecting the sheet are provided at a discharge port of the transport path 6. Sensor 20 is axis 2
A lever 20B that rotates about 0A,
And a detection element 20C for detecting the rotation of B.

The auxiliary stacking section 7 includes a rear end support guide 21 for supporting the rear end of the discharged sheet, an auxiliary stacking tray 22 rotatable about a shaft 22A, and a sensor 23 for detecting the presence or absence of a sheet. It has. The sensor 23 includes a lever 23B that rotates around a shaft 23A, and a detection element 23C that detects the rotation of the lever 23B.

The transport path 8 is formed by guide plates 12 and 17 which are opposed to each other with an interval at which a sheet can pass.

A switching guide 24 for distributing the sheet supplied to the transport path 5 to the transport path 6 and the transport path 8 is mounted rotatably about a shaft 24A, and is driven by a driving device such as a solenoid (not shown). It can be switched.

Further, discharge rollers 25 and 26, an auxiliary roller 27, and an auxiliary roller 27
Alignment belt 2 interposed between the roller and the discharge roller 26
8 are provided. The discharge alignment belt 28 prevents the trailing end of the sheets discharged by the discharge rollers 25 and 26, and aligns the sheets stacked on the processing tray 9 to the lower end alignment reference portion 9A.

The processing section 10 includes an inclined processing tray 9,
The presence or absence of a sheet on the processing tray 9 and the guide plate 45
Sensor 29 (detection means) for detecting the forward / backward movement of the sheet, a guide plate 30 for guiding the sheets accommodated in the processing tray 9 toward the lower end alignment reference portion 9A, and a side edge reference portion 31 An alignment unit 32 that is movable in the width direction to be aligned to the side, a stapler 33 that binds a sheet bundle aligned between the side edge reference unit 31 and the alignment unit 32,
Conveying means for discharging the sheet on the processing tray 9, for example, a discharge roller 34, a variable means 35 for varying the frictional force between the discharge roller 34 and the sheet, and discharging the sheet with the sheet interposed between the discharge roller 34 Elevating roller 3
6 and a shaft 37 that supports the elevating roller 36 so as to be able to move up and down.
A rotating member 37 that rotates about A and a paddle 43 that rotates in the counterclockwise direction in FIG. 2 to scrape the sheet on the processing tray 9 toward the lower end alignment reference portion 9A are provided.

The conveying means is not limited to the discharge roller 34 but may be a belt or a paddle. The lifting roller 3
6. The rotating member 37 forms a part of a pressing means capable of pressing the sheet against the conveying means.

As shown in FIG. 1, the stacking section 11 includes a stacking tray 39 rotatably mounted on a frame 38 about a shaft 39A, and a spring 40 for urging the stacking tray 39 upward.
And descends about the axis 39A by the weight of the sheets stacked on the stacking tray 39.

As shown in FIG. 3, an engaging portion 37B and a leaf spring 42 are provided on the side surface of the rotating member 37, and an abutting portion 41B of the rotating member 41 which rotates about a shaft 41A is engaged with the engaging portion 37B. When the rotating member 41 is rotated in the reverse direction, the lifting roller 36 is lowered as shown in FIG.

The sensor 29 has a shaft 29 as shown in FIGS.
A lever 29B that rotates about A, and this lever 29B
And a detection element 29C for detecting the rotation of. The lever 29B is provided with an engaging portion 29D for detecting the operation of the variable means 35.

The sensor 29 can detect both the presence or absence of a sheet on the processing tray 9 and the detection that the guide plate 45 has been intentionally pressed.

The variable means 35 supports at least a part of the sheets stacked on the processing tray 9 as shown in FIGS. 7 and 8, and reduces the engagement between the sheets and the discharge roller 34 as the conveying means. A sheet support member, for example, a curved guide plate 45 is provided which is movable between a support position and a retracted position retracted from the support position. The guide plate 45 is supported rotatably about a shaft 45A, and is urged toward the support position by urging means 46 such as a spring. Note that the guide plate 45 may protrude from the peripheral surface of the discharge roller 34 toward the sheet at the support position, or may be located at the same position (in the same plane) as the peripheral surface of the discharge roller 34. Further, the sheet supporting member is not limited to a plate-shaped member, but may be a rod-shaped member.

The guide plate 45 has an engaging portion 45B which engages with the leaf spring 42 as shown in FIGS. 3 to 6, and a pressing portion 45 which presses the engaging portion 29D of the sensor 29 as shown in FIGS.
C.

For this reason, when the leaf spring 42 comes into contact with the engaging portion 45B due to the lowering of the rotating member 37, the guide plate 45 moves to the retracted position as shown in FIG. 4 or FIG. That is, when the sheet is conveyed from the processing tray 9, the driving unit that retreats the guide plate 45 to the retreat position is the leaf spring 4.
2 and an engagement portion 45B. Accordingly, pressing means such as the rotating member 37 to which the leaf spring 42 is attached and the rotating member 41 for raising and lowering the rotating member 37 are also driving means.

When the guide plate 45 is pushed by an operator's finger or the like, the guide plate 45 is retracted, and the pressing portion 45C shown in FIG.
By pressing 9D, the lever 29B rotates counterclockwise in FIG. 8 and is detected by the detection element 29C. That is, the guide plate 45
Is detected by the sensor 29 to have moved to the retreat position side against the urging force of the urging means 46. Therefore, when the driving means is not retracting the guide plate 45, the sensor 2
When 9 detects the movement of the guide plate 45 to the retreat position side, the control means (not shown) determines that there is an abnormality.

Next, the rollers 15, 18, 25, 27, 3
4. The configuration of the driving mechanism such as the rotating member 37 and the guide plate 45 will be described.

As shown in FIGS. 9 and 10, the driving mechanism includes a pulley 51 attached to the rotating shaft of the motor 50, a tension pulley 52, a pulley 53 attached to the rotating shaft 15A of the transport roller 15, and a discharge roller. 18 rotating shafts 1
8A, and a pulley 5 attached to the rotation shaft 55 of the discharge roller 25 and the auxiliary roller 27.
6 and a gear 57, and a pulley 58 are provided. Each pulley is drivingly connected by a belt 59, and the transport roller 15, the discharge roller 18, the discharge roller 25, and the auxiliary roller 27 are driven.

Further, a gear 60 meshing with the gear 57 and a gear 61 coaxial with the gear 60 are provided.

The gear 61 has a shaft 62 as shown in FIGS.
The gear 62 rotating about A is meshed. The gear 62 has a notch 63A and the first gear 6
3, a notch hole 64A and a second gear portion 64, and a drive pin 65 that engages with the engaging portion 41C of the rotating member 41 to drive the rotating member 41. The gear 66 meshes with the first gear 63, and the gear 66 meshes with the second gear 64.

The gear 66 is a rotating shaft 34A of the discharge roller 34.
Gear 67 attached to the gear.

On the other hand, a solenoid 70 and a gear 71 with a stopper are provided to engage the first gear portion 63 with the gear 61 from a state in which the notch 63A faces the gear 61.

The solenoid 71 is provided with a locking member 72 that rotates around a fulcrum and a spring 73 that biases the locking member 72. A stopper 71B and a hook 7 which are locked by a locking member 72
1C is provided, and is urged by a spring 74 so as to be able to rotate clockwise about a shaft 71A in a state in which it meshes with the first gear portion 63 and the second gear portion 64.

<Operation> Next, the operation will be described with reference to the flowcharts of FIGS.

When the copying operation of the image forming apparatus 4 is started, the motor 50 is driven before the leading end of the sheet reaches the transport path 5.
Is driven. Thereby, the transport roller 15, the discharge roller 18, the discharge roller 25, and the auxiliary roller 27 rotate.
The switching guide 24 is switched according to the operation mode (S1) in FIG.

The operation modes include a non-job mode, a long job mode, a jog mode, and a staple mode.

The non-job mode is a mode for discharging sheets to the auxiliary stacking unit 7.

The long job mode is a mode in which the sheet is discharged to the stacking unit 11 without performing the processing operation in the processing unit 10.

In the jog mode, the stacking position of the first page of each sheet bundle is shifted by the processing unit 10 and conveyed.
In this mode, the sheet is discharged so as to be sorted for each sheet bundle.

The staple mode is a mode in which each sheet bundle is stapled by the stapler 33 and discharged to the stacking unit 11.

Therefore, in the non-job mode,
The switching guide 24 rotates clockwise in FIG. 2, and in the long job mode, the jog mode, and the staple mode, the switching guide 24 rotates counterclockwise in FIG.

(1) Non-job mode In the non-job mode, the switching guide 24 rotates clockwise in FIG. 2, and the sheet is discharged to the auxiliary stacking unit 7 via the transport paths 5 and 6.

(2) Long Job Mode In the long job mode, when the entrance sensor 14 detects the leading edge of the sheet (S2), the activation timer of the solenoid 70 is set (S3). This timer is used for transport route 8
Is set to the time when the trailing edge of the sheet supplied to the printer will pass through the discharge roller 25.

When the time is up (S4), the solenoid 70 is activated for a predetermined time. Thereby, the locking member 72 is sucked as shown in FIG. 10, and the lock of the stopper 71B of the gear 71 with the stopper is released. Thus, the gear 71 with the stopper rotates clockwise by the urging force of the spring 74.

As a result, the gear 62 rotates counterclockwise, the drive pin 65 disengages from the engagement portion 41C, the rotating member 41 rotates counterclockwise, and the lifting roller 36 descends as shown in FIG. At this time, since the leaf spring 42 presses the engagement portion 45B, the guide plate 45 retreats, and the discharge roller 34 projects.

On the other hand, the rotation of the gear 71 with the stopper causes the first gear portion 63 to mesh with the already rotated gear 61, and the gear 62 continues to rotate counterclockwise. Thus, the second gear portion 64 meshes with the gear 66, and the discharge roller 34 rotates counterclockwise via the gear 67. At this time, since the elevating roller 36 descends and is in contact with the discharge roller 34, it is driven to rotate. When the gear 62 rotates and the drive pin 65 pushes up the engaging portion 41C of the rotating member 41, the rotating member 41 rotates clockwise and the rotating member 37 rises, and then the notch 63A is The drive is turned off to face the stopper 61, and the stopper 71 </ b> B is locked by the locking member 72.

In this state, the sheet is supplied to the processing tray 9, and the lever 29B is pushed by the sheet and the sensor 2 is pressed.
Reference numeral 9 indicates that the sheet has been supplied. At this time, since the guide plate 45 is at the support position, the discharged sheets are stacked without engaging the discharge rollers 34, and the sheet ends are not bent or skewed as shown in FIG. P is stacked over the processing tray 9 and the stacking unit 11.

Since the sheet is continuously supplied from the image forming apparatus 4, when the leading edge of the next sheet is detected by the entrance sensor 14 (S2), the solenoid 70 is excited after a predetermined time (S5). The operation lowers the elevating roller 36 and retracts the guide plate 45. For this reason,
The rotating discharge roller 34 is exposed and engages with the lower surface of the sheet, and the sheet sandwiched between the discharge roller 34 and the lowered elevating roller 36 is discharged to the stacking unit 11. The above operation is repeatedly performed, and a plurality of sheets are stored in the stacking unit 11. The stacking tray 39 of the stacking unit 11 descends against the urging force of the spring 40 due to the weight of the sheet.

(3) Jog Mode When a plurality of originals are copied into a plurality of sheets by the image forming apparatus 4, the first sheet (S7) of the first copy is processed in the processing tray 9 and the When the sheet is discharged over the stacking unit 11, the guide plate 45 supports the lower surface of the sheet, so that the discharge roller 34 does not contact the sheet, and is rotated by the inclination of the processing tray 9 and the driving device (not shown). By the rotation of the driven paddle 43 and the rotation of the discharge alignment belt 28, the sheet is abutted against the lower end alignment reference portion 9A. Then, the aligning means 32 moves the sheet side edge to the side edge reference portion 3.
After being pressed against 1 and aligned, it is retracted.

The second sheet (S7) is the entrance sensor 14
(S8), the solenoid 70 is detected as in S3.
Is set (S9), and when the time is up (S10), the solenoid 70 is started (S1).
1).

During this time, the second sheet is discharged onto the first sheet, and the lower end is aligned by the lower end alignment reference portion 9A. For the second and subsequent sheets, the aligning means 32 is at the retracted position and no aligning operation is performed. Therefore, the first sheet and the second sheet are shifted in the width direction.

When the lifting roller 36 descends and nips the first and second sheets between the discharge roller 34, the two sheets are discharged to the stacking unit 11 at the same time. The first and second sheets are stacked on the stacking unit 11 while being shifted in the width direction.

The third and subsequent sheets are discharged to the stacking unit 11 in the same manner as in the long job mode without performing the aligning operation on the processing tray 9.

When the last sheet of the first copy is discharged and the first sheet of the second copy is discharged, the same operation as that of the first copy is performed. Therefore, the first sheet of the second set is shifted and stacked on the uppermost sheet of the first set of the stacking unit 11, so that the first sheet and the second sheet are stacked.
It is classified as a part. The above operation is repeated for the required number of copies.

(4) Staple mode When the sheets are stapled by the stapler 33, the side edges of the sheets are aligned by the aligning means 32 each time the sheets are stacked over the processing tray 9 and the stacking unit 11, and a predetermined number of sheets are stacked. Then, binding is performed by the stapler 33 (S12). And
As in S3, the activation timer of the solenoid 70 is set (S13), and when the time is up (S14), the solenoid 70 is excited (S15).

Therefore, as shown in FIG. 5, the elevating roller 36 is pressed onto the sheet bundle P bound by the stapler 33, and the guide plate 45 is retracted, and the rotating discharge roller 34 is moved to the sheet bundle P. And the sheet bundle P is discharged to the stacking unit 11 in a state where the sheet bundle P is nipped by the discharge roller 34 and the elevating roller 36. The above operation is repeated for the required number of copies.

(5) Operation of Sensor 29 The sensor 29 detects whether or not there is a sheet on the processing tray 9 and can detect that the guide plate 45 is intentionally pressed. . The detection operation is performed as follows.

First, as shown in FIG. 15, it is checked whether the motor 50 is operating (S21). If the motor 50 is operating, it is checked whether a sheet exists in the apparatus (S22). For example, after the first sheet is detected by the entrance sensor 14, the processing tray 9
Then, it is checked whether or not a predetermined time has elapsed until a predetermined number of sheets are discharged and stapled and discharged from the processing tray 9.

If the predetermined time has elapsed, it is determined that there is no sheet in the apparatus, and if the sensor 29 is turned on (S2).
3) Assuming that an external force is applied to the guide plate 45 by a finger or the like, the motor 50 is stopped (S4). That is, while the motor 50 is operating, when the sensor 29 is not in a state of detecting a sheet, if the sensor 29 is turned on, a hand or the like is put in the discharge port and the motor 50 is stopped because it is dangerous.
Ensure safety.

If the sensor 29 is off (S23), the operation is continued.

If the predetermined time has not elapsed since the entrance sensor 14 detected the sheet (S22), the sensor 29 is turned on (S26) after the elapse of the predetermined time after the start of the sheet bundle discharge operation (S25). It is determined that a sheet bundle remains in the area (S27). If the sensor 29 is off (S26), it means that the sheet has been normally discharged.

While the motor 50 is stopped (S21), if the power is turned on (S28), it is checked whether the sensor 29 is on (S29), and if it is on, sheets remain on the processing tray 9. Jam as it remains (S
30).

<Modifications> Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and for example, the following modifications are possible.

In the above embodiment, the movement of the guide plate 45, which is the sheet supporting member, to the retracted position is linked to the elevating operation of the rotating member 37 to which the elevating roller 36 is attached. However, another drive such as a solenoid or a motor is used. The sheet supporting member may be directly driven by means to move between the supporting position and the retracted position. Further, the driving unit may move the sheet support member from the support position to the retreat position when the discharge roller 34 serving as the conveyance unit starts conveying the sheet at least.

Further, when the sheet supporting member is retracted, it is not necessary for the sheet supporting means to be completely separated from the lower surface of the sheet. It is only necessary that the frictional force with the seat be reduced.

In the above embodiment, the stacking of the sheets by the stacking means and the retreat of the sheet supporting member from the supporting position are detected by one detecting means, but may be detected by separate detecting means. That is, the presence / absence detection means for detecting the presence / absence of a sheet on the stacking means and the retreat detection means for detecting that the sheet support member has retreated from the support position may be provided. Therefore, when the evacuation detecting means detects evacuation of the sheet support member from the support position while the driving means is not retreating the sheet support member to the evacuation position, it is determined that there is an abnormality.

[0066]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an overall configuration of a sheet processing apparatus.

FIG. 2 is a cross-sectional view illustrating a configuration of a main mechanism of the sheet processing apparatus.

FIG. 3 is a diagram illustrating a state where a sheet support member is at a support position.

FIG. 4 is a diagram illustrating a state where a sheet support member has moved to a retracted position.

FIG. 5 is a diagram illustrating a state in which a sheet bundle is sandwiched between a discharge roller and a lifting roller.

FIG. 6 is a diagram showing a configuration of a sheet supporting means and a detecting means.

FIG. 7 is a diagram showing the configuration and operation of a sheet supporting means and a detecting means.

FIG. 8 is a diagram showing the configuration and operation of a sheet supporting means and a detecting means.

FIG. 9 is a diagram showing the configuration and operation of a drive mechanism.

FIG. 10 is a diagram showing the configuration and operation of a drive mechanism.

FIG. 11 is a view showing a structure of a part of a gear of a driving mechanism.

FIG. 12 is a diagram showing a structure of a part of a gear of a driving mechanism.

FIG. 13 is a diagram showing a structure of a part of a gear of a driving mechanism.

FIG. 14 is a flowchart showing an operation according to a mode.

FIG. 15 shows whether or not the sheet is present and the sheet support member is retracted by one.
6 is a flowchart for detection by two detection means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sheet processing means 4 Image forming apparatus 9 Processing part 11 Stacking part 29 Sensor 34 Discharge roller 35 Variable means 42 Leaf spring 45 Guide plate

Claims (6)

[Claims] 1. A sheet loading apparatus comprising: loading means for loading at least one supplied sheet; and transport means for transporting a sheet in contact with the sheet loaded on the loading means. A sheet support member that supports at least a portion of the upper sheet and that is movable between a support position for reducing engagement of the sheet and the conveying means and a retracted position retracted from the support position; And a driving unit for moving the sheet between the supporting position and the retreat position. 2. The sheet according to claim 1, wherein the driving unit moves the sheet supporting member from the supporting position to the retreat position at least when the conveying unit starts conveying the sheet. Loading device. 3. The driving means has a pressing means capable of pressing a sheet against the conveying means, and interlocks with the pressing operation of the pressing means to move the sheet supporting member between the supporting position and the retracted position. 2. The method according to claim 1, wherein the moving is performed between
A sheet stacking apparatus according to claim 1. 4. An urging means for urging the sheet support member toward the support position, and a detecting means for detecting that the sheet support member has retreated from the support position against the urging force of the urging means. 2. The sheet stacking apparatus according to claim 1, further comprising means. 5. A control for judging an abnormality when the detecting means detects the retreat of the sheet support member from the support position while the driving means is not performing the movement operation of the sheet support member to the retreat position. 5. The sheet stacking apparatus according to claim 4, further comprising means. 6. A detecting means which is activated by stacking of sheets by said loading means or a retreat of said sheet support member from said supporting position, and said detecting means is operated after a supplied sheet is discharged from said loading means. Control means for determining that the sheet support member is retracted, and when the detecting means is operated before the supplied sheet is discharged from the loading means, it is determined that the sheet is loaded by the loading means. The sheet accumulating apparatus according to claim 1, wherein: