JP2002087682A - Loading tray and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a loading tray capable of regularly loading sheets and increasing the loading amount of the sheets, and an image forming device such as a copier, a facsimile, a printer, or a printing machine, equipped with the loading tray. SOLUTION: This loading tray 38 has a movable tray 42 loading carried sheets, and being displaced between a first position and a second position locating in the upper position than the first position; and a tray driving means 43 letting displace the movable tray 42 between the first position and the second position, and an image forming device is equipped with this loading tray 38.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a stacking tray such as a paper discharge tray or a double-sided tray, and an image forming apparatus having the same, such as a copying machine, a facsimile, a printer, or a printing machine.

[0002]

2. Description of the Related Art Generally, image forming apparatuses such as copying machines, facsimile machines, printers, and printing machines are provided with a stacking tray for stacking conveyed sheets, such as a discharge tray or a double-sided tray. There are two main functions required for such a stacking tray: orderly stacking of sheets, and stacking more sheets.

However, the conveyed sheet is apt to curl depending on the type. Such sheet properties hinder the function of the stacking tray in order to stack sheets. Also, the curl of the sheet is an image forming apparatus that transports the sheet in the vertical direction when performing transfer and fixing, and performs stacking in a substantially horizontal direction, in other words, an image in which the transport path of the sheet after fixing is greatly curved. It is likely to occur in forming equipment. When stacking curled sheets, it is difficult to stack sheets neatly if the head from the sheet discharge port to the stacking tray is large, especially if the sheets are small in size or large in curl. Not only does it make it difficult to load sheets.

As a method for solving such a problem, in order to stack the sheets neatly, the head from the sheet discharge port to the stacking tray is made as small as possible, and the sheets coming out of the sheet discharge port are stacked on the stacking tray before the sheets are completely rounded. It is possible to land. However, if the drop is reduced, the number of sheets that can be stacked on the stacking tray is reduced, so that the above-described function of stacking more sheets is hindered.

Further, when the loading tray is a so-called inner tray provided in a space exposed outside the image forming apparatus, when a scanner is provided above the loading tray,
For example, when an image forming apparatus having a stacking tray is designed so that a post-processing device can be installed, the space above the stacking tray is reduced, and the function of stacking more sheets is hindered. In addition, there are problems such as difficulty in viewing the sheets on the stacking tray, difficulty in taking out and handling the sheets, difficulty in mounting a post-processing device, and difficulty in maintenance of the stacking tray. Also, when the loading tray is a double-sided tray provided inside the image forming apparatus, there is a problem that maintenance of the loading tray is difficult to perform.

As described above, in order to secure the function of stacking sheets neatly, it is necessary to reduce the drop between the stacking tray and the sheet discharge port. However, when the drop is reduced, more sheets are stacked. Function and other functions are impaired. That is, to stack sheets neatly and to stack more sheets,
These are conflicting demands.

In order to satisfy this conflicting demand, the present applicant has disclosed in Japanese Patent Application No. 11-357021 that an auxiliary member is arranged so as to be able to be raised and lowered on a discharge tray which is a stacking tray, and a normal sheet is stacked. Sometimes, the auxiliary member is turned down and stored, and when stacking a curled sheet, the auxiliary member is raised to substantially reduce the drop from the sheet discharge port.

[0008]

However, with this technique, although a certain effect can be obtained, it is necessary to manually raise and lower the auxiliary member, which is troublesome.
Another problem is that it is difficult to determine what condition should be used for the undulation. In addition, once the auxiliary member is raised and the sheets are stacked, it is difficult to lay the auxiliary member down until the sheet is taken out.Therefore, a space above the stacking tray such as a scanner is disposed above the stacking tray. If the sheet is small, there is a problem that the stacking amount of sheets is reduced, and since the sheets are supported above the stacking tray main body, it is difficult to see the sheets on the stacking tray, and it is difficult to remove and handle the auxiliary members. There is the same problem as when not equipped.

[0009] The present invention solves the above-mentioned disadvantages of such a conventionally proposed technique, allows sheets to be stacked neatly, and
It is an object of the present invention to provide a stacking tray capable of stacking more sheets and an image forming apparatus having the same, such as a copier, a facsimile, a printer, and a printing machine.

[0010]

According to a first aspect of the present invention, there is provided a movable tray for loading conveyed sheets, wherein the movable tray occupies a first position and a higher position than the first position. A loading tray having a movable tray displaceable between a second position and a loading tray having a tray driving means for displacing the movable tray between a first position and a second position.

According to a second aspect of the present invention, there is provided a tray body which occupies a fixed position and on which sheets to be conveyed are stacked, a first position which is integral with the tray body, and a second position which occupies a higher position than the first position. A loading tray having a movable tray that can be displaced between positions, the tray having a tray driving unit that displaces the movable tray between a first position and a second position.

According to a third aspect of the present invention, in the loading tray according to the first or second aspect, at least a part of the stacking tray is provided in the space of the image forming apparatus having a space opened to the outside. I do.

The invention described in claim 4 is the first to third aspects of the present invention.
In the loading tray according to any one of the above, the movable tray is configured to load the sheet conveyed in a state where the movable tray occupies any position from the first position to the second position. .

[0014] The invention according to claim 5 provides the invention according to claims 1 to 4.
The sheet tray according to any one of the above, further comprising a sheet conveyance detecting means for detecting that a sheet is conveyed toward the stacking tray.

According to a sixth aspect of the present invention, in the stacking tray according to the fifth aspect, when the sheet conveyance detecting means detects that a sheet is conveyed, the tray driving means sets the movable tray to a sheet. Is set to any one of the loading positions from the first position to the second position for loading.

According to a seventh aspect of the present invention, in the loading tray according to the sixth aspect, the sheet conveyance detecting means is provided at a predetermined distance from the movable tray.

According to an eighth aspect of the present invention, in the stacking tray according to the fifth or sixth aspect, when the sheet conveyance detecting means does not detect that a sheet is conveyed for a predetermined time, the tray driving means includes When the movable tray is not at the first position, the movable tray is displaced to the first position.

According to a ninth aspect of the present invention, in the loading tray according to the eighth aspect, the sheet conveyance detecting means is provided near the movable tray.

According to a tenth aspect of the present invention, in the stacking tray according to any one of the first to ninth aspects, the tray driving means is configured to control the movable tray to move the uppermost sheet position on the movable tray. It is characterized by being displaced so as to be substantially constant.

According to an eleventh aspect of the present invention, in the stacking tray of the tenth aspect, there is provided a sheet position detecting means for detecting that the uppermost sheet position on the movable tray has reached a predetermined position, The driving means displaces the movable tray downward by a predetermined amount when the sheet position detecting means detects that the uppermost sheet position on the movable tray has reached a predetermined position.

According to a twelfth aspect of the present invention, in the loading tray according to the tenth or eleventh aspect, the movable tray is a first tray.
When the sheet position detecting means detects that the uppermost sheet position on the movable tray has reached a predetermined position in a state where the position is occupied, the stacking of sheets is prohibited.

According to a thirteenth aspect of the present invention, in the stacking tray according to any one of the tenth to twelfth aspects, when the movable tray occupies the first position, the sheet position detecting means operates the movable tray. When detecting that the uppermost uppermost sheet position has reached a predetermined position, there is provided output means for performing an output for displaying that sheets cannot be stacked.

According to a fourteenth aspect of the present invention, in the loading tray according to any one of the first to thirteenth aspects, the movable tray is disposed substantially horizontally.

According to a fifteenth aspect of the present invention, in the stacking tray according to the fourteenth aspect, the tray driving means is displaced so as to move the movable tray substantially vertically in parallel.

According to a sixteenth aspect of the present invention, there is provided an image forming apparatus having the stacking tray according to any one of the first to fifteenth aspects.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In this embodiment, an image forming apparatus of an intra-cavity paper discharge type having a space partially open to the outside and having an exposed space is employed. The present invention can be applied to an apparatus and an image forming apparatus of an intra-cavity paper discharge type and having a paper discharge tray on the outer surface of the apparatus. FIG. 1 shows an image forming apparatus which is a copying machine to which the present invention is applied.

The image forming apparatus 1 includes an apparatus main body 2 serving as an image forming apparatus main body, an original reading scanner installed on the uppermost surface of the apparatus main body 2, and an auto document feeder (not shown) installed on the upper surface of the reading scanner. That is, it is mainly composed of a well-known reading device 8 composed of an ADF. The image forming apparatus 1 is capable of forming an image on a recording material (hereinafter, referred to as “paper”) as various sheets such as plain paper, thick paper, an envelope, and an OHP sheet.

The apparatus main body 2 has a tray 38 serving as a discharge tray, which is a stacking tray, as a bottom portion, and a lower surface of the reading device 8 as an upper portion thereof. The surface has a space 100 open to the outside. Since the reading device 8 has a well-known configuration, the description of the configuration and functions will be omitted.

The apparatus main body 2 has a so-called substantially vertical transport path configuration in which a sheet feeding section 20 is located below the image forming section 18 and a sheet discharging section 22 is located above the image forming section 18. In the vicinity of one side on the right side in FIG. 1 of the main body 2, a target image is formed while being conveyed substantially vertically from below to above, and is discharged from a discharge port 10 through a discharge roller pair 12. I have.

In the image forming section 18, an electrostatic latent image is formed on a photosensitive drum 26 by a writing unit 24 based on image data transmitted from the reading device 8 or a personal computer. 28
Is visualized. Reference numeral 29 denotes a developer supply device for supplying the developer to the developing unit 28.

When a sheet is selected by an operator's operation of an operation panel (not shown) or automatic sheet selection and image formation is started, a plurality of sheet cassettes 20 of the sheet feeding section 20 are started.
The paper selected by the paper feed roller 11 is fed from one of the corresponding ones of a and 20b. The paper is a photosensitive drum 26
The timing of the upper visualized toner image with respect to the leading edge of the image is adjusted by the registration roller 30 and conveyed to the transfer section, and the toner image is transferred to a sheet by the transfer roller 32 as transfer means. The sheet on which the toner image has been transferred is conveyed to a fixing device 34 having a fixing roller 7 that generates heat and a pressure roller 9 that is in pressure contact with the fixing roller 7, and is fixed.

The tray 38 has a curved surface on which the discharge port 10 side falls, and the trailing edge of the sheet is aligned by the trailing edge regulating portion forming one wall surface of the space 100 due to the weight of the sheet. The front end side of the tray 38 in the sheet transport direction is substantially horizontal, and the tray 38 is arranged substantially horizontally as a whole.

As shown in FIGS.
Are a tray body 41 occupying a fixed position and loaded with conveyed paper, a first position shown in FIGS. 4 and 5 which is integral with the tray body 41, and FIGS. 3 and 6 occupying a higher position than the first position. ,
Movable tray 42 displaceable between the second position shown in FIG.
And tray driving means 43 for displacing the movable tray 42 between the first position and the second position.

As shown in FIGS. 2 and 3, the movable tray 4
2 has a flat plate portion 44 which is flush with the tray main body 41 at the first position and which is disposed substantially horizontally as a whole, and a leg 45 which is disposed on the lower surface side of the flat plate portion 44. . The flat plate portion 44 holds the tray main body 41 in the direction perpendicular to the plane of FIG.
It is located in the central part. The legs 45 are arranged in pairs at the front and the rear in the sheet transport direction. At the tip of each leg 45, a vertically long convex portion 46 is provided so as to protrude toward the tray main body 41 side.

A guide member 47 is disposed at a position corresponding to each leg 45 of the tray body 41.
A long hole 48 for slidably receiving the convex portion 46 is formed in 7. As a result, the movable tray 42 moves substantially parallel in the vertical direction, so that it can be freely displaced between the first position and the second position. Convex part 46, long hole 4
The size of 8 is such that the movable tray 42 moves smoothly without rattling.

The tray driving means 43 includes a motor 49, an arm 51 swinging about a shaft 50, a shaft 50 and the motor 4.
A coupling 53 that connects the shaft 52 of the ninth and the movable tray 42 is biased in a direction to bring the tray main body 41 and the movable tray 42 closer to each other. The motor 49 is a stepping motor, and can control the rotation amount of the arm 51. By the rotation of the motor 49, the distal end of the arm 51 is engaged with the back surface of the flat plate portion 44 to displace the movable tray 42 between the first position and the second position. With the movable tray 42 occupying any position from the first position to the second position,
The transported paper is loaded.

The tray 38 is provided with the tray 3 on the apparatus main body 2 side.
And a sheet conveyance detecting unit for detecting that the sheet is conveyed toward the sheet No. 8. More specifically, the sheet conveyance detecting means includes a filler 5 disposed near the tray 38 on the downstream side of the sheet discharge roller pair 12 in the sheet conveyance direction, as shown in FIG.
5 and a start key (not shown) provided on an operation panel (not shown).

The filler 55 is provided so as to be able to contact the paper on the tray 38, and also serves as a sheet position detecting means for detecting that the uppermost paper position has reached a predetermined position. The predetermined position is a position in which the tray 38 occupies any position between the first position and the second position, and the highest paper position is at the height of the stacking limit. is there. The fact that the loading limit has been reached is determined by the displacement amount of the filler 55. When the filler 55 detects that the uppermost sheet position or the flat plate portion 44 has reached a predetermined position, the motor 49 is driven and the movable tray 42 is displaced downward by a predetermined amount. This predetermined amount means that the topmost sheet position on the movable tray 42 after the displacement or the height difference between the flat plate portion 44 and the discharge port 10 indicates that the sheets are curled properly even if the sheets are curled. Is within the range in which is possible. In this embodiment, the predetermined amount is 5 mm, and the uppermost sheet position is displaced so as to be substantially constant. This predetermined amount is desirably set within a range of 3 mm to 10 mm.

When the start key is pressed and an output command is issued as shown in FIG. 8, paper feeding is started, and it is detected that paper is being conveyed to the tray 38. When driven, the movable tray 42 moves up. When the filler 55 detects the top sheet on the flat plate portion 44 or the movable tray 42, the motor 49 rotates in the reverse direction,
By lowering the movable tray 42 by a predetermined amount, the movable tray 4
2 is adjusted in position so that the sheets can be stacked neatly. If there is no paper on the movable tray 42, the movable tray 42 occupies the second position. Movable tray 42
The paper is stacked, and the movable tray 42 is displaced downward each time the filler 55 detects the paper, and the position adjustment is repeated.

When the movable tray 42 occupies the first position and is integrated with the tray main body 41, the filler 5
5 outputs a detection signal, the movable tray 42 cannot be further displaced downward.
Has the maximum amount of sheets loaded, and cannot load any more sheets. Therefore, when the filler 55 outputs the detection signal in a state where the movable tray 42 is in the first position, the rotation of the sheet feeding roller 11 is stopped, and the tray 38 is stopped.
In addition to prohibiting the stacking of the sheets, a message indicating that the stacking of the sheets by the tray 38 is impossible is displayed on the operation panel. That is, the filler 55 also functions as an output unit that performs an output for displaying that the sheets cannot be stacked on the tray 38.

When the image formation of the number of sheets set on the operation panel is completed and the discharge of the last sheet is completed, the detection signal by the filler 55 is not transmitted, and the filler 5 is stopped.
If it is not detected that the sheet is conveyed toward the movable tray 42 by the predetermined time period, it is determined whether or not the position of the movable tray 42 is the standby position, that is, the first position. In the case of the standby position, the movable tray 4 is
2 is returned to the standby position. The predetermined time is set to 5 seconds in the present embodiment. However, the predetermined time depends on the time interval required for image formation, the paper conveyance speed, and the like, and may be set between 5 seconds and 10 seconds. desirable.

At the start of image formation, the movable tray 42 is moved after the sheet conveyance detecting means detects the conveyance of the sheet.
In order to make the time required for the sheet to be discharged to the movable tray 42 longer than the time required for adjusting the position of the movable tray 42 to the predetermined position, the position of the sheet transport detecting means is determined by the movable tray 42 with respect to the transport path of the sheet. It is desirable to be as far away as possible. Therefore, the sheet conveyance detection means needs to be disposed at a predetermined distance from the movable tray 42. Here, the predetermined distance is a time required from the time when the sheet conveyance detection unit detects the conveyance of the sheet to the time when the sheet is discharged to the movable tray 42, to adjust the position of the movable tray 42 to the predetermined position. A distance that is longer than time. Therefore, the sheet conveyance detection means can be provided not in the start key but in the paper conveyance path at a predetermined distance or more from the movable tray 42. If the presence / absence of actual paper conveyance is detected, the movable tray 42 will not be displaced when the start key is pressed but no paper is set in the paper feed cassettes 20a and 20b.

However, the start key also requires a longer time from the detection of sheet conveyance until the sheet is discharged to the movable tray 42 than the time required to adjust the position of the movable tray 42 to a predetermined position. Therefore, it can be said that the movable tray 42 is disposed at a predetermined distance from the movable tray 42. The input and output of the signals for controlling the movable tray 42 are performed by a CPU (not shown) as control means.

Although the present embodiment has been described above, the stacking tray may be not only a discharge tray but also a double-sided tray used in an image forming apparatus for forming a double-sided image. In the embodiment, the tray main body occupies a fixed position and the movable tray is driven independently of the tray main body. However, the entire tray main body can be moved up and down to be a movable tray. The sheet conveyance detecting means and the sheet position detecting means may be constituted by separate sensors. A sensor for moving the movable tray to the second position may be provided separately from the sheet position detecting means. In this case, the movable tray can be quickly moved to the second position. The space 100 only needs to be open at least on the paper take-out side. The movable tray occupies the first position when the image formation is completed or when the image formation is stopped, so that it is easy to check and take out the paper on the paper discharge tray. The image forming apparatus 1 may form a color image including full color instead of a monocolor image as in the embodiment, or may form an image on both sides of a sheet instead of forming an image on one side. There may be.

[0045]

According to the present invention, a movable tray for loading conveyed sheets, the movable tray being displaceable between a first position and a second position occupying a higher position of the first position. In the loading tray having
And the second position, it is possible to provide a stacking tray capable of stacking sheets neatly and stacking more sheets.

According to the present invention, the tray main body occupying the fixed position for loading the conveyed sheets, the first position integrated with the tray main body, and the second position occupying the upper position of the first position.
In the stacking tray having a movable tray that can be displaced between the first position and the second position, since the movable tray has a tray driving unit that is displaced between the first position and the second position, sheets can be stacked neatly, In addition, it is possible to provide a stacking tray on which more sheets can be stacked.

If the stacking tray is provided in the space of the image forming apparatus having at least a part of the space open to the outside, the presence and absence of sheets can be confirmed and taken out despite being provided in the space. Can easily provide a loading tray.

When the sheets conveyed are loaded in a state where the movable tray occupies any position from the first position to the second position, the movable tray is set to a position suitable for receiving the sheets. Thus, it is possible to provide a stacking tray capable of stacking sheets neatly and stacking more sheets.

If there is a sheet conveyance detecting means for detecting that a sheet is conveyed toward the stacking tray, a stacking tray capable of displacing the movable tray based on the sheet detection by the sheet conveyance detecting means is provided. Can be provided.

When the sheet conveyance detecting means detects that the sheet is conveyed, the tray driving means moves the movable tray to one of the first position to the second position for stacking the sheets. With the loading position, the movable tray can be displaced based on the detection of the sheet by the sheet conveyance detection unit, and a loading tray that can displace the movable tray as needed can be provided.

If the sheet conveyance detecting means is disposed at a predetermined distance from the movable tray, it is possible to provide a stacking tray capable of securing the sheets to be stacked after displacing the movable tray to a predetermined position.

When the sheet conveyance detecting means does not detect that the sheet is conveyed for a predetermined time, the tray driving means
If the movable tray is displaced to the first position when the movable tray is not at the first position, the movable tray is set to the first position at the end of image formation and the like, and it is easy to check for the presence or absence of a sheet and take out the sheet. A loading tray can be provided.

If the sheet conveyance detecting means is arranged near the movable tray, it is possible to provide a stacking tray capable of detecting the completion of image formation and the like with high accuracy.

If the tray driving means displaces the movable tray so that the position of the uppermost sheet on the movable tray is substantially constant, it is possible to provide a loading tray capable of always loading sheets satisfactorily. it can.

There is provided sheet position detecting means for detecting that the uppermost sheet position on the movable tray has reached a predetermined position, and the tray driving means determines that the uppermost sheet position on the movable tray is If the movable tray is displaced downward by a predetermined amount when it is detected that the predetermined position has been reached,
It is possible to provide a stacking tray that can always satisfactorily stack sheets and secure the maximum amount of stackable sheets.

When the sheet position detecting means detects that the uppermost sheet position on the movable tray has reached the predetermined position in a state where the movable tray occupies the first position, if the sheet stacking is prohibited, the movable sheet can be moved. A stacking tray capable of preventing overflow of sheets from the tray and jamming of sheets can be provided.

When the sheet position detecting means detects that the uppermost sheet position on the movable tray has reached the predetermined position in a state where the movable tray occupies the first position, it is impossible to stack sheets. Is provided, an easy-to-use stacking tray can be provided to the user, for example, when the stacking of sheets is prohibited, the reason can be understood.

If the movable tray is disposed substantially horizontally,
A stacking tray capable of stably stacking sheets can be provided.

If the tray driving means is displaced so as to move the movable tray substantially in the vertical direction, it is possible to provide a stacking tray which displaces the movable tray without disturbing the sheet stacking state.

According to the image forming apparatus having the stacking tray of the present invention, it is possible to provide an image forming apparatus having a stacking tray exhibiting the above-mentioned effects and having high user reliability and high usability.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a stacking tray to which the present invention is applied and an image forming apparatus having the same.

FIG. 2 is an exploded perspective view of the loading tray shown in FIG.

FIG. 3 is a side view of a main part showing a state in which a movable tray occupies a second position in the stacking tray shown in FIG. 1;

FIG. 4 is a perspective view of the loading tray showing a state where the movable tray occupies a first position.

FIG. 5 is a side view of the loading tray shown in FIG. 4;

FIG. 6 is a perspective view of the loading tray showing a state where the movable tray occupies a second position.

FIG. 7 is a side view of the stacking tray shown in FIG. 6;

FIG. 8 is a control flow of a movable tray based on a sheet conveyance state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 41 Tray main body 42 Movable tray 43 Tray driving means 55 Sheet conveyance detection means, sheet position detection means, output means near movable tray 100 Space

Claims (16)

[Claims] 1. A movable tray for stacking conveyed sheets, the second tray occupying a first position and a higher position than the first position.
A movable tray that can be displaced between a first position and a second position, wherein the movable tray has a tray driving unit that displaces the movable tray between a first position and a second position. 2. A tray body which occupies a fixed position and on which sheets to be conveyed are stacked, and a displacement between a first position which is integral with the tray body and a second position which is higher than the first position. A stacking tray having a movable tray, comprising: tray driving means for displacing the movable tray between a first position and a second position. 3. The stacking tray according to claim 1, wherein at least a part of the stacking tray is provided in the space of the image forming apparatus having a space open to the outside. 4. The stacking tray according to claim 1, wherein the movable tray is conveyed while occupying any position from a first position to a second position. A loading tray for loading incoming sheets. 5. The stacking tray according to claim 1, further comprising a sheet conveyance detecting means for detecting that a sheet is conveyed toward the stacking tray. . 6. The stacking tray according to claim 5, wherein, when the sheet conveyance detecting means detects that the sheet is conveyed, the tray driving means sets the movable tray to load the sheet. A loading tray, which is any loading position from a first position to a second position. 7. The stacking tray according to claim 6, wherein said sheet conveyance detecting means is disposed at a predetermined distance from said movable tray. 8. The stacking tray according to claim 5, wherein, when the sheet conveyance detecting means does not detect that a sheet is conveyed for a predetermined time, the tray driving means comprises:
When the movable tray is not at the first position, the movable tray is displaced to the first position. 9. A stacking tray according to claim 8, wherein said sheet conveyance detecting means is provided near said movable tray. 10. A stacking tray according to claim 1, wherein said tray driving means controls said movable tray such that the uppermost sheet position on said movable tray is substantially constant. A loading tray characterized by being displaced. 11. The loading tray according to claim 10, wherein:
Sheet position detecting means for detecting that the uppermost sheet position on the movable tray has reached a predetermined position, wherein the tray driving means determines that the sheet position detecting means is the uppermost sheet position on the movable tray; A movable tray that is displaced downward by a predetermined amount when it is detected that the loading tray has reached a predetermined position. 12. The stacking tray according to claim 10, wherein when the movable tray occupies the first position, the sheet position detecting means sets the uppermost sheet position on the movable tray to a predetermined position. A stacking tray for prohibiting stacking of sheets when the stacking tray is detected. 13. The stacking tray according to claim 10, wherein when the movable tray occupies the first position, the sheet position detecting means sets the uppermost sheet on the movable tray. A loading tray comprising output means for outputting an indication that loading of sheets is not possible when detecting that the position has reached a predetermined position. 14. The loading tray according to claim 1, wherein said movable tray is disposed substantially horizontally. 15. The loading tray according to claim 14, wherein:
The loading tray, wherein the tray driving means is displaced so as to move the movable tray substantially in a vertical direction. 16. An image forming apparatus comprising the stacking tray according to claim 1.