JP2006089198A - Sheet stacking device and image forming device with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a sheet stacking device with a full-fill notifying function and a full-fill detecting function capable of obtaining excellent stacking performance. <P>SOLUTION: This sheet stacking device is provided with an ejection tray, in which sheets from the ejection part is stacked, an arm supported in one end thereof by an arm supporting means provided over the ejection part and having a free end to be directly, or through a contact member, brought in contact with the tray or the sheets stacked in the tray on a downstream side of the support end in the sheet ejecting direction and having one or more bent parts projecting upward and provided between the free end and the support end and having flexibility in at least one part thereof, a deflection regulating part for regulating the upper limit of each of the bent parts of the arm in order from the support end to the free end with rise of the free end, full-fill notifying sensors 14 and 24 for detecting that each of the bent parts is regulated by the deflection regulating part, and full-fill sensors 15 and 25 for detecting that the free end of the arm reaches the upper limit when the free ends rise more in the condition wherein all the bent parts are regulated in the upper limit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet accumulating apparatus with a full notice and full detection function and an image forming apparatus provided with the same.

In a sheet depositing apparatus that deposits sheets output from an image forming apparatus or the like, it is required to orderly deposit sheets at predetermined positions while maintaining the order of discharged sheets, that is, good stacking properties. For this reason, a technique is known in which a sheet pressing arm that prevents the discharged sheet from jumping upstream in the discharge direction is disposed on the sheet receiving base (for example, see Patent Document 1).
Further, the number of sheets that can be stacked is limited regardless of the number of sheets. For this reason, when the discharged sheet is almost full, the user is prompted to remove the accumulated sheet, or the full detection or full notice detection is performed to stop the discharge of the sheet from the image forming apparatus. It is desirable to have. And the technique which can implement these detection with a simple structure is desired. For this reason, a technique is known in which the stacking height detection means of a plurality of sheet stacking means that can be moved up and down independently is performed by one detection mechanism (for example, see Patent Document 2).
JP-A 64-8180 JP 2000-177911 A

  In recent years, with the downsizing of the apparatus, there are an increasing number of multifunction machines in which the outer shape of the apparatus is formed in a “U” shape and the discharged sheets are deposited in the central space. In such a multi-function machine, a sheet stacking apparatus that can obtain a sufficient number of stacked sheets and good stacking properties for sheets discharged to a limited size area is particularly desired. In many cases, a “movable job separator” or the like is provided as a sheet stacking device for branching a sheet discharge destination according to a plurality of print processing modes such as a printer, a copier, and a fax machine.

  Conventionally, the mechanisms for full notice or full detection and stacking performance have been different. However, as the demand for more compact devices increases, simplification of the structure and miniaturization are desired. Further, a structure that can cope with a case where the apparatus has a plurality of sheet stacking portions such as a movable job separator is preferable.

  The present invention provides a sheet stacking apparatus that can obtain a good stacking property with a simple structure, can perform full notice or full detection, and can also be applied to an apparatus having a plurality of sheet stacking units. .

  The present invention provides a sheet discharge tray for accumulating sheets discharged from the sheet discharge unit, and a sheet pressing arm having at least a part of the flexibility, and is supported by an arm support member disposed above the sheet discharge unit. A support end that is supported by the end of the sheet, a free end that comes in contact with a sheet stacked on the sheet discharge tray or the sheet discharge tray at a downstream side of the sheet discharge direction from the support end, and the support end and the support end An arm having one or more bent portions protruding upward and formed between the free end, and an upper limit position of each bent portion of the arm that is disposed above the arm and rises while bending as the arm free end rises. If the arm has a plurality of bent parts, the upper limit is sequentially controlled from the bent part on the support end side to the bent part on the free end side as the free end rises. Deflection regulating part, full warning sensor provided corresponding to each bending part to detect that each bending part is in a state regulated by the deflection regulating part, and a state where all bending parts are restricted to the upper limit And a full sensor for detecting that the free end of the arm has reached the upper limit when the free end of the arm is raised.

  The sheet stacking apparatus according to the present invention is a sheet pressing arm, at least a part of which is flexible, and an arm having one or more bent portions that are arranged between a support end and a free end and are convex upward. And a deflection restricting portion for restricting the upper limit position of each bent portion of the arm, so that the bent portion and the free end of the sheet pressing arm are accumulated on the sheet discharge tray by detecting a state where the bending restricting portion restricts. In addition, it is possible to improve the stackability of sheets and to detect a full notice and fullness corresponding to one or more sheet stacking heights with a single arm. That is, it is possible to realize a good stacking property of the stacked sheets with a simple structure and to detect one or more stacked sheets. As a result, a compact, reliable, and inexpensive sheet full notice or full detection mechanism can be realized. The sheet stacking apparatus of the present invention is applied to a case where a large amount of sheets are stacked in a limited space to make the sheet stacking apparatus compact, or to a job separator provided with the detection mechanism in each of a plurality of discharge trays. This is particularly suitable.

  A sheet stacking apparatus according to the present invention includes a sheet discharge tray for stacking sheets discharged from a sheet discharge unit, and a sheet pressing arm at least a part of which is flexible, and is disposed above the sheet discharge unit. A support end whose one end is supported by the support member, a free end that contacts the sheet discharge tray or a sheet deposited on the sheet discharge tray downstream of the support end in the sheet discharge direction, or directly through the contact member; An arm having one or more bent portions protruding upward and formed between the support end and the free end, and each bent portion of the arm which is disposed above the arm and rises while bending as the arm free end rises Bending restriction portion for restricting the upper limit position of the arm, and when the arm has a plurality of bent portions, the bent portion on the free end side is bent from the bent portion on the support end side as the free end rises. Sequentially upper limit deflection control part, full warning sensor provided corresponding to each bending part to detect that each bending part is in a state regulated by the bending restriction part, and all bending parts are upper limit And a full sensor for detecting that the free end of the arm has reached an upper limit when the free end of the arm further rises from the restricted state.

  Here, the term “arm has flexibility” means that the arm can be elastically deformed in accordance with a change in the stacking height of the sheet or the height from the sheet discharge tray to the arm support member. Also, the deflection restricting portion refers to a portion that has a function of restricting the rise of the free end of the arm and the bent portion of the arm that rises with the rise so that it does not rise above a predetermined height. Accordingly, it is arranged so that the upper limit of the rise of each bent portion or the free end is sequentially controlled. Further, the support end of the arm may be fixed to the arm support member. However, the support end is not limited to this. For example, the arm is pivoted so as to rotate as the free end of the arm rises, and the spring of the arm's own weight or axial rotation direction is supported. It may be attached so as to press the discharge tray or the stacked sheets by force. The contact member is a member that comes into contact with the sheet to such an extent that it does not interfere with the progress of the sheet when it receives the conveyance force from the paper discharge roller. It may be.

  The full notice or full sensor may be, for example, a push switch that detects that a bent portion or a free end of an arm comes into contact with a deflection regulating portion, but is not limited thereto, and the arm is in a predetermined position. Anything that can be detected is acceptable. For example, when the arm is in contact with the deflection regulating portion, it can be realized by using a photo interrupter arranged so as to block the optical path from the light emitting portion to the light receiving portion. In addition, a magnetic sensor or a magnetic permeability sensor may be used.

  Alternatively, the sheet stacking apparatus according to the present invention includes a sheet discharge tray for depositing sheets discharged from the sheet discharge unit and a flexible sheet pressing arm having an arm support member disposed above the sheet discharge unit. A support end on which one end is supported; a free end contacting the sheet stacked on the sheet discharge tray or the sheet discharge tray downstream of the support end directly or via a contact member; and the support end An arm having a curved portion formed between the free end, a deflection regulating portion that is disposed above the arm and regulates an upper limit position of the curved portion that rises while bending as the arm free end rises; As the free end rises, each point corresponds to each point to detect a state in which one or more points of the curved portion are successively restricted from the point on the support end side to the point on the free end side. A full notification sensor provided, and a full sensor that detects that the free end has reached the upper limit when the free end of the arm further rises from the state in which all the full notification sensors detect the upper limit regulation state. And

In this way, even when the arm does not have one or more bent portions but has a curved shape, a full notice and fullness corresponding to one or more stacked heights of the sheets stacked on the paper discharge tray are obtained. It can be detected by a single arm. Therefore, it is possible to realize detection of a plurality of sheet stacking heights with a simple structure.
In addition, the free end of the arm or the contact member attached to the free end is in contact with the output tray when no sheets are stacked on the output tray, and is the highest when the sheets are stacked on the output tray. It may be configured to contact the sheet deposited on the substrate.

The deflection regulating portion regulates the upper limit of the arm by having its lower surface abutted against each bending portion or bending portion of the arm, and each full notification sensor is a deflection regulating where each point of each bending portion or bending portion of the arm abuts. You may make it arrange | position on the surface of a part.
In this way, since the upper limit restriction of each part of the arm due to contact with the deflection restricting part is directly detected, accurate detection can be realized with a simple detection mechanism, and a cheap and highly reliable seat full notice and Full detection can be realized.

  The discharge tray is a movable tray that moves up and down, and either the full notification sensor or the full sensor is configured to function to detect the upper limit of tray movement when the discharge tray is moved up or down. May be. According to the above configuration, the upper limit detection of the tray movement can be combined with the full notification sensor or the full sensor, so there is no need to provide a dedicated detection sensor or detection mechanism for detecting the upper limit of the tray movement. Accordingly, it is possible to realize a movable tray control mechanism that is simple in structure, inexpensive and highly reliable.

When the sheet discharge tray accumulates sheets, the full notification sensor is full at the second tray position raised by a predetermined distance from the first tray position where sheets are deposited between the previous sheet discharge and the next sheet discharge. Return to the first tray position after detection by the sensor or both,
6. A sheet stacking apparatus according to claim 5, wherein the sheet stacking height on the sheet discharge tray is obtained based on detection results of the full notification sensor at the second tray position, the full sensor, or both.

  Further, the sheet discharge tray moves between the previous sheet discharge and the next sheet discharge to the second tray position that is elevated by a predetermined distance from the first tray position where the sheets are accumulated, and the full notice sensor, the full sensor or After detection by both of these sensors, the level returns to the first tray position, and the degree of sheet stacking height on the discharge tray based on the detection results of the full notification sensor, the full sensor, or both of the two tray positions. May be obtained. In this way, the degree of sheet accumulation height can be obtained from the detection results of the full notification sensor, the full sensor, or both sensors at the second tray position, so the sheet accumulation height can be obtained only at the first tray position. Compared to the case where the thickness is detected, the sheet stacking height at twice the level can be detected, and a more detailed state can be obtained with respect to the sheet stacking height.

  Alternatively, the deflection regulating unit is movable up and down, and either the full notice sensor or the full sensor functions to detect the lower limit of the deflection regulating unit movement when the deflection regulating unit is moved up and down. You may comprise as follows. For example, this configuration corresponds to a case where the deflection regulating member is disposed on the lower surface of the movable tray and moves up and down as the tray moves. With such a configuration, the lower limit detection of the movement of the deflection regulating portion can be combined with the full notification sensor or the full sensor, so there is no need to provide a dedicated detection sensor or detection mechanism for detecting the lower limit of the deflection regulating portion movement. Accordingly, it is possible to realize a movable tray control mechanism that is simple in structure, inexpensive and highly reliable. Further, when the deflection regulating member is disposed on the lower surface of the movable tray, the lower limit of the tray movement can be detected by such a configuration.

  The deflection regulating unit moves between a previous sheet discharge and a next sheet discharge to a second position that is lowered by a predetermined distance from the first position for discharging the sheet, and a full notice sensor, a full sensor, or both sensors After the detection by, the position returns to the first position, and the level of the sheet stacking height on the sheet discharge tray is obtained based on the detection results of the full notification sensor, the full sensor or both of them in the second position. Good. In this way, since the degree of the sheet stacking height can be obtained from the detection results of the full notification sensor, the full sensor or both of them in the second position, the sheet stacking height of only the first position can be obtained. Compared to the case where detection is performed, it is possible to detect the sheet accumulation height in more stages, and it is possible to know the level of the sheet accumulation height in more detail.

  Further, a sheet removal forgetting sensor that detects the presence or absence of a sheet may be further provided in a region on the sheet discharge tray where sheets are accumulated. In this way, it is possible to detect that a sheet remains on the sheet discharge tray even if the sheet stacking height is equal to or less than the detection of the full notice. Accordingly, it is possible to prompt the user to forget to remove the sheet and prompt the user to empty the paper discharge tray. For example, when printing with an image forming apparatus that discharges a large number of sheets at a time, the image prompts the user to detect that the user has forgotten to remove the sheet and to empty the tray before starting image formation. This is effective for preventing the paper discharge tray from becoming full during formation. Alternatively, as described above, when the upper and lower limits of the tray movement are shared by the full notice or the full sensor, the upper limit or the lower limit position may not be constant due to the influence of the sheets accumulated on the tray. In such a case, if you want to accurately control the upper or lower position of the tray, detect forgetting to remove the sheet before moving the tray, and if you forget to remove the sheet, do not move the tray and wait for the sheet to be removed. It is also possible to control to move the tray afterwards.

  Alternatively, the sheet stacking apparatus according to the present invention is movable up and down, and is configured to deposit a sheet from the sheet discharge unit below the sheet discharge unit and a sheet from the sheet discharge unit above the sheet discharge unit. A movable tray disposed at the time of discharging the sheet at any of the retreat positions where the sheet is not accumulated, and a sheet pressing arm at least a part of which is flexible, and is supported by an arm support member disposed above the sheet discharging unit. A support end that is supported by the end of the sheet, a free end that contacts the movable tray or a sheet deposited on the movable tray downstream of the support end in the sheet discharge direction, and the support end and the support end A first arm having one or more bent portions formed on the upper side and formed between the free end and the first arm; Detects the first deflection regulating portion that regulates the upper limit position of each bent portion that rises with the rise of the free end of the first arm, and that each bent portion of the first arm is in a state regulated by the first deflection regulating portion. And a movable tray full warning sensor provided corresponding to each bent part of the first arm, and when the free end of the first arm further rises with the upper part of the bent part of the first arm restricted. When the sheet stack height reaches the upper limit and the movable tray is detected to be full, and the movable tray is moved up and down, the free end of the first arm approaches a predetermined distance from the first deflection regulating portion. A movable tray full sensor that regulates the upper limit of the movable tray by detecting the sheet, a fixed tray that accumulates sheets discharged when the movable tray is in the retracted position, and at least a part of the deflection A sheet pressing arm having a support end, one end of which is supported by an arm support member disposed on the lower surface of the movable tray, and is deposited on the fixed tray or the fixed tray downstream of the support end in the sheet discharging direction. A second arm having a free end that contacts the formed sheet directly or via a contact member, and one or more bent portions formed between the support end and the free end, and an upwardly convex bent portion; and a movable tray A second deflection restricting portion that restricts the limit position of the bent portion that approaches the movable tray as the second arm free end approaches the lower surface of the movable tray, and the bent portion of the second arm restricts the second deflection. A fixed tray full warning sensor disposed on the lower surface of the movable tray corresponding to the bent portion of the second arm to detect that the movable tray is in a state regulated by the portion, and the movable tray When the free end of the second arm approaches the lower surface of the movable tray while the bent portion of the second arm is restricted, the stack height of the stacked sheets reaches the upper limit and the fixed tray is full When the movable tray is moved up and down, it is detected that the free end of the second arm has approached a predetermined distance from the lower surface of the movable tray and the fixed tray is full to regulate the lower limit of the movable tray And a sensor.

Furthermore, the sheet stacking apparatus of the present invention may further include a display unit that displays information based on detection of the full notification sensor or the full sensor. In this way, based on the detection result of the sensor, one or more stages of sheet full notice and sheet full status display are performed on the display unit to inform the user of the state of sheet stacking height, and at an appropriate time. The user can be prompted to take action to remove the deposited sheet. Alternatively, the position of the movable tray or the deflection regulating member can be displayed as necessary to notify the user. Alternatively, when the movable tray or the deflection regulating member is moved, it is possible to determine that there is an abnormality in the detection of the upper limit and the lower limit position and display the abnormal state on the display unit.
The image forming apparatus according to the present invention includes any one of the above-described sheet deposition apparatuses.

Hereinafter, an embodiment of the present invention will be described based on the embodiments shown in the drawings.
(Embodiment 1)
In this embodiment, an overall structure of an embodiment of a sheet deposition apparatus according to the present invention and an embodiment of an image forming apparatus provided with the same will be described below.
FIG. 3 is an explanatory diagram showing a configuration example of the image forming apparatus according to this embodiment. As shown in FIG. 3, the image forming apparatus according to this embodiment is roughly composed of a scanner unit, a printing unit, and a sheet conveying unit as other parts.

  The scanner unit irradiates light on a document and generates image data corresponding to the image of the document from the reflected light. The printing unit forms a visible image based on the image data generated by the scanner unit, and prints the visible image on a predetermined transfer sheet (sheet). The sheet conveying unit supplies the sheet to the printing unit and discharges the printed sheet. Further, the sheet conveying unit includes a roller driving mechanism which is a characteristic configuration of the image forming apparatus. This configuration will be described later.

  Next, the configuration of each part of the image forming apparatus will be described. First, the scanner unit will be described. The scanner unit has a document table 101 made of transparent glass on the upper surface. A scanner optical system is disposed below the document table 101. The scanner optical system includes an exposure light source 102, a reflecting mirror 103, an imaging lens 104, and a photoelectric conversion element (CCD) 105. The exposure light source 102 is a light source 102 for irradiating light on a document placed on the document table 101. The reflecting mirror 103 guides the reflected light from the document to the imaging lens 104 and the CCD 105 as indicated by a straight line in the drawing, for example. The CCD 105 receives reflected light imaged by the imaging lens 104 and generates an electrical signal corresponding to the reflected light as an image signal.

Next, the printing unit and the sheet conveying unit will be described. The printing unit includes a photosensitive roller 111, a charging unit 112, a developing unit 113, a transfer charger 114, a fixing roller 115, a cleaning device 116, a laser scanning unit (LSU) 117 (not shown), and a fixing paper detection switch. The photosensitive roller 111 is a drum-shaped photosensitive roller 111, and is driven to rotate so that a sheet conveyed through a main conveyance path 121, which will be described later, is in contact with the surface of the photosensitive roller 111 at the same speed. The charging unit 112 charges the surface of the photosensitive roller 111 to a predetermined potential. The LSU 117 scans the surface of the charged photosensitive roller 111 by scanning a laser beam in a direction parallel to the rotation axis of the photosensitive roller 111, thereby reading the surface of the photosensitive roller 111 from the scanner unit. An electrostatic latent image corresponding to the image signal of the original is formed. The developing unit 113 develops the electrostatic latent image formed on the surface of the photosensitive roller 111 using the LSU 117 with the developing roller 118, and forms a toner image (a visible image) on the surface of the photosensitive roller 111. . The transfer charger 114 transfers the toner image on the photosensitive roller 111 to a sheet. The fixing roller 115 heat-fixes the unfixed toner image transferred to the printed sheet on the sheet. The fixing paper detection switch detects that the sheet has passed the fixing roller 115.
The cleaning device 116 removes the toner remaining on the surface of the photosensitive roller 111 after the toner image is transferred to the sheet.

The sheet conveyance unit includes a main conveyance path 121, a sub conveyance path 122, a fixed sheet feeding cassette 123, a pickup roller 124, a registration roller 125, a guide member 126, a sheet discharge port 127, a sheet discharge roller 128, and a conveyance roller 129. A pre-registration detection switch is provided. The fixed paper feed cassette 123 is for storing sheets for printing.
The pick-up roller 124 is a half-moon-shaped roller for outputting sheets one by one from the fixed sheet feeding cassette 123. The pre-registration detection switch is for detecting that the sheet conveyed by the pickup roller 124 has passed a predetermined position on the main conveyance path 121 and outputting a predetermined detection signal. The registration roller 125 temporarily holds the sheet conveyed through the main conveyance path 121. The sheet has a function of transporting the sheet with good timing in accordance with the rotation of the photosensitive roller 111 so that the leading edge of the toner image on the photosensitive roller 111 can be transferred in synchronization with the leading edge of the sheet. That is, the registration roller 125 conveys the sheet based on the detection signal output by the pre-registration detection switch so that the leading edge of the toner image on the photosensitive roller 111 is synchronized with the leading edge of the printing range on the sheet.

  The paper discharge roller 128 is provided in the vicinity of the paper discharge port 127 and allows the sheet discharged from the fixing roller 115 to be fed into the first paper discharge tray 130 or the second paper discharge tray 131 (fixed paper feed below the scanner unit). It is a roller for discharging to a movable tray disposed on the upper portion of the cassette 123. The paper discharge roller 128 has a function as a back surface printing mechanism together with the guide member 126 and the sub transport path 122. That is, in normal single-sided printing, the guide member 126 is arranged in the B direction in FIG. 3 and can convey the sheet from the main conveyance path 121 to the paper discharge roller 128. On the other hand, when printing on both sides of the sheet, when printing on the first side of the sheet is completed and the trailing edge of the sheet is discharged from the main conveyance path 121, the guide member 126 is rotated in the A direction to discharge the sheet. The sheet reversely fed from the roller 128 is disposed so as to be guided to the sub conveyance path 122. The paper discharge roller 128 rotates in the forward direction (the direction in which the sheet is output from the paper discharge port 127) until the trailing edge of the sheet output from the fixing roller 115 passes through the guide member 126, and then in the reverse direction. Rotate. Thus, the sheet passes through the guide member 126 and is conveyed to the sub-conveying path 122, and is conveyed again to the registration roller 125 by the conveying roller 129, and printing is performed on the second surface (back surface).

FIG. 1 is an explanatory view showing a configuration example of a sheet stacking apparatus according to this embodiment. The sheet volume device shown in FIG. 1 shows a case where sheets discharged from the discharge roller 128 in the direction of arrow C are accumulated on the first discharge tray 130. FIG. 1A shows a state in which there is no sheet in the first paper discharge tray. In this state, the free end of the sheet pressing arm 21 is in contact with the first paper discharge tray 130 via a roller attached to the free end. Yes. As the sheets are discharged and accumulated on the first paper discharge tray 130, the free end of the arm 21 is raised by the accumulated sheets.
Since the material of the arm 21 is, for example, a phosphor bronze flat plate and has flexibility, the arm 21 is bent before and after the bent portion as the free end rises. When the amount of accumulated sheets increases, the bent portion of the arm 21 eventually hits the deflection regulating portion 23. A full warning sensor 24 made of, for example, a micro switch is provided at a portion where the bent portion of the arm 21 abuts against the deflection regulating portion 23. When the bent portion of the arm 21 presses an actuator provided on the sensor, Detect and output full warning signal. FIG. 1B shows a state in which the bent portion of the arm 21 rises and the bent portion of the arm 21 comes into contact with the deflection regulating portion 23 and the full notification sensor 24 outputs a full notification signal. When the amount of accumulated sheets further increases from this state, the free end side of the arm 21 bends more than the bent portion of the arm 21 and the free end of the arm 21 rises. The free end roller hits the deflection regulating portion 23. A full sensor 25 made of, for example, a micro switch is provided at the portion where the roller at the free end of the arm 21 abuts against the deflection restricting portion 23, and this is detected and a full signal is output. FIG. 1C shows a state where the free end of the arm 21 rises and the full sensor 25 outputs a full signal.

  FIG. 2 is an explanatory diagram showing different states of the sheet stacking apparatus according to this embodiment. In FIG. 2, the discharged sheets are accumulated on the second paper discharge tray 131. FIG. 2A shows a state in which there is no sheet in the second paper discharge tray. In this state, the free end of the sheet pressing arm 11 is in contact with the second paper discharge tray 131 via a roller attached to the free end. Yes. As the sheets are discharged and accumulated on the second sheet discharge tray 131, the free end of the arm 11 is raised by the accumulated sheets. The material of the arm 11 is, for example, a phosphor bronze flat plate and has flexibility. Therefore, the arm 11 is bent before and after the bent portion as the free end rises. When the amount of accumulated sheets increases, the bent portion of the arm 11 eventually hits the deflection regulating portion 13. A full warning sensor 14 made of, for example, a micro switch is provided at a portion where the bent portion of the arm 11 abuts against the deflection regulating portion 13. When the bent portion of the arm 11 presses an actuator provided on the sensor, Detect and output full warning signal. FIG. 2B shows a state in which the bent portion of the arm 11 rises and the bent portion of the arm 11 comes into contact with the deflection regulating portion 13 and the full notice sensor 14 outputs a full notice signal. If the sheet accumulation amount further increases from this state, the bent portion of the arm does not rise because it is in contact with the deflection regulating portion, but the free end is bent more than the bent portion of the arm 11 and the free end rises. To do. Then, the free end roller hits the deflection regulating portion 13. A full sensor 15 made of, for example, a micro switch is provided at a portion where the roller at the free end of the arm 11 abuts against the deflection restricting portion 13, and this is detected to output a full signal. FIG. 2C shows a state where the free end of the arm 11 is raised and the full sensor 15 outputs a full signal.

  In this embodiment, the sheet stacking apparatus having the first and second discharge trays is shown, but the configuration may be such that only one discharge tray is provided. Full warning and full detection can be performed by a sheet pressing arm made of an elastic member having a bent shape, a deflection regulating portion, and two sensors.

(Embodiment 2)
In this embodiment, a case will be described in which the sheet pressing arm has a shape having a plurality of bent portions and includes a plurality of full notification sensors corresponding to the respective bent portions.
FIG. 5 is an explanatory view showing a case where the sheet pressing arm has two bent portions in the sheet stacking apparatus of the present invention. A first full notice sensor 24 and a second full notice sensor 27 are arranged corresponding to each bent portion. For simplicity, FIG. 5 shows only the sensor for the first paper discharge tray. As the sheets are discharged and accumulated on the first paper discharge tray 130, the free end of the arm 21 is raised by the accumulated sheets. The arm 21 bends before and after the bent portion as the free end rises. When the amount of accumulated sheets increases, the bent portion on the most support end side of the arm 21 eventually hits the deflection regulating portion 23. A first full warning sensor 24 is provided at a portion where the bent portion abuts against the deflection regulating portion 23. When the bent portion of the arm 21 presses an actuator provided on the sensor, this is detected and detected. A full warning signal is output. FIG. 5A shows a state in which the first full notification sensor 24 outputs a first full notification signal.

  If the amount of accumulated sheets increases further from the above-described state, the bent portion on the support end side of the arm does not rise because it is in contact with the deflection regulating portion, but it does not hit the first full notification sensor 24 of the arm 21. The free end side of the arm 21 is bent with respect to the bent portion, and the free end of the arm 21 is raised. The bent portion on the free end side hits the deflection regulating portion 23. A second full sensor 27 is provided at a portion where the bent portion on the free end side of the arm 21 abuts against the deflection regulating portion 23, and this is detected and a second full notice signal is output. FIG. 5B shows a state in which the second full notification sensor 27 outputs a full signal.

If the sheet accumulation amount further increases from the above-described state, the two bent portions of the arm do not rise because they are in contact with the deflection regulating portion, but the bent portion on the free end side of the arm 21 and the free end And the free end of the arm 21 rises. The free end roller hits the deflection regulating portion 23. A full sensor 25 made of, for example, a micro switch is provided at the portion where the roller at the free end of the arm 21 abuts against the deflection restricting portion 23, and this is detected and a full signal is output. FIG. 5C shows a state in which the free end of the arm 21 rises and the full notice sensor 24 outputs a full signal.
As described above, a multistage full notice can be detected using the shape of the sheet pressing arm having a plurality of bent portions.

(Embodiment 3)
In this embodiment, a case where the sheet pressing arm has a curved shape will be described.
FIG. 6 is an explanatory view showing a case where the sheet pressing arm has a curved shape in the sheet stacking apparatus of the present invention. For simplicity, FIG. 6 shows only the sensor for the first paper discharge tray. FIG. 6A shows a state in which there is no sheet in the first paper discharge tray. In this state, the free end of the sheet pressing arm 21 is in contact with the first paper discharge tray 130 via a roller attached to the free end. Yes. As the sheets are discharged and accumulated on the first paper discharge tray 130, the free end of the arm 21 is raised by the accumulated sheets. The arm 21 bends in the curved portion as the free end rises. When the amount of accumulated sheets increases, the curved portion on the support end side of the arm 21 eventually hits the deflection regulating portion 23. A full warning sensor 24 and a full sensor 25 are provided at a portion where the arm 21 abuts against the deflection regulating portion 23, and the full warning sensor 24 is disposed on the support end side of the arm 21. When the bending portion rises as the free end rises, the full notification sensor 24 first detects that the arm 21 has come into contact with the deflection regulating portion 23 and outputs a full notification signal. FIG. 6B shows a state in which the full notice sensor 24 outputs a full notice signal.

  When the sheet accumulation amount further increases from the above-described state, the free end of the arm 21 rises due to the bending between the free end side of the curved portion and the free end of the arm 21. The free end roller hits the deflection regulating portion 23. A full sensor 25 is provided at a portion where the roller at the free end of the arm 21 abuts against the deflection restricting portion 23, and a full signal is output by detecting the abutment of the free end. FIG. 6C shows a state where the full notice sensor 24 outputs a full signal.

As described above, a multistage full notice can be detected using the shape of the sheet pressing arm having a plurality of bent portions.
In this embodiment, the case where there is one full notification sensor and one full sensor is shown. However, as described in the second embodiment, a plurality of full notification sensors are arranged to detect multi-stage full notifications. It may be.

(Embodiment 4)
As shown in FIGS. 1 and 2, when the second discharge tray is a movable tray, for example, after the power is turned on, an initialization operation is performed to know the absolute position of the tray and place the tray at a predetermined position. There is a need to. Then, it is necessary to prevent the discharge tray from exceeding the vertical movable range during the initialization operation. In order to realize this, it is necessary to provide a sensor for detecting that the paper discharge tray is at the upper limit position or the lower limit position of the movable range. The absolute position of the paper discharge tray can be obtained by detecting that the paper discharge tray is at the lower limit position or the upper limit position and obtaining the subsequent movement distance. For example, when the paper discharge tray is driven by a stepping motor, the absolute position can be obtained by counting the number of moving steps from the upper limit position or the lower limit position to positive or negative according to the moving direction. Or you may obtain | require by attaching an encoder to the axis | shaft of a drive motor, and adding / subtracting the number of pulses of an encoder according to a moving direction.

  The upper limit or lower limit position may be detected by providing a dedicated sensor, but the above-described full notice sensor or full sensor can be used for this purpose to simplify the structure.

  FIG. 4 is an explanatory diagram illustrating the state of the sensor at the upper limit position and the lower limit position when the upper limit and lower limit positions of the second discharge tray are detected using the full notice sensor or the full sensor. FIG. 4A shows a state where the second paper discharge tray is at the lower limit position. When the tray is at the lower limit position, the roller at the free end of the sheet pressing arm 21 is pressed against the first paper discharge tray 130, and the bent portion of the arm 21 turns on the full notification sensor 24. In the tray initialization state, it can be detected that the tray is in the lower limit position when the sensor is changed to ON when the full sensor 24 is moved downward from the OFF state.

  In this case, if sheets are stacked on the first paper discharge tray, the absolute position of the tray cannot be detected correctly. Therefore, when the forgetting sheet sensor 26 is equipped, when the forgetting sheet sensor detects the sheet, the user may be prompted to remove the sheet by performing a notification before the initialization operation. In this way, the full sensor and the tray lower limit sensor can be used together with one sensor.

  On the other hand, FIG. 4B shows a state where the second paper discharge tray is at the upper limit position. When the tray is at the upper limit position, the roller at the free end of the arm 21 pushed up from the lower side to the second paper discharge tray 131 turns on the full sensor 15. In the initialization state of the tray, it can be detected that the tray is in the upper limit position when the full sensor 15 is moved upward from the OFF state and the state of the sensor changes to ON.

In this case, if sheets are accumulated on the second paper discharge tray, the absolute position of the tray cannot be detected correctly. Therefore, when the forgetting sheet sensor 16 is equipped, when the forgetting sheet sensor detects the sheet, the user may be prompted to remove the sheet by performing a notification before the initialization operation. In this way, a full sensor and a tray upper limit sensor can be used together with one sensor.
Not only the example of this embodiment but also the tray lower limit position can be detected by the full sensor 25, and the tray upper limit position can also be detected by the full notice sensor 14. These methods may be appropriately selected according to the shape of the tray or arm, and are obvious to those skilled in the art.

(Embodiment 5)
In this embodiment, the display of information based on the full height notice sensor or the height of the accumulated sheet detected by the full sensor, the upper limit position of the movable tray or the lower limit position of the deflection regulating portion will be described. Furthermore, a method for performing multi-stage full notice detection by detecting the state of the full notice sensor and the full sensor by moving the movable tray or the deflection restricting section periodically to the discharge tray by a predetermined distance between sheet discharges will be described. .

  When the fullness of the paper discharge tray is detected by the full sensor as described in the second to fourth embodiments, the discharge of sheets may be stopped so that no more sheets are discharged to the paper discharge tray. As a countermeasure in this case, the sheets accumulated on the paper discharge tray must be removed by the user's hand. This is because a new sheet cannot be discharged until the sheet is removed. Therefore, it is preferable to have means for informing the user to remove the sheets accumulated on the paper discharge tray. In particular, in a sheet stacking apparatus of an image forming apparatus having a scanner unit above the paper discharge tray as shown in FIG. 3, it may be difficult to see the state of the stacked sheets with the paper discharge tray hidden behind the scanner unit. It is preferable to have the notification means. In this case, simply notifying the full state prompts the user to remove the sheet after the sheet cannot be discharged, which is a follow-up measure. Instead, it is preferable to notify the state before the accumulated sheet is full, that is, a full notice. In this case, it is expected that the sheet is removed before the paper discharge tray is full, and the process continues without stopping due to the full paper tray.

  In the second to fourth embodiments, since the full notice sensor is provided in addition to the full sensor, the user can be prompted to remove the sheet before the discharge tray becomes full. Furthermore, if a full-stage full notice detection or a forgetting sheet detection is performed, the user can be notified of the state of the paper discharge tray in more detail.

  FIG. 8 is an explanatory diagram showing an example of a display unit for informing the user of the state of the paper discharge tray. 8A and 8B correspond to the sheet stacking apparatus with a job separator shown in FIG. FIG. 8A shows an example in which one level of full notice and full detection are performed. The display unit 30 is provided with a display lamp 31 for displaying the sheet accumulation state of the lower first sheet discharge tray 130 and a display lamp 32 for displaying the sheet accumulation state of the upper second sheet discharge tray 131. Yes. The display lamps 31 and 32 are both turned on when the tray is full, and blinks when the tray is full. In other states, it is off.

For example, as shown in FIG. 1A, when no sheets are stacked on the first paper discharge tray 130 and the second paper discharge tray 131, both the display lamps 31 and 32 are turned off.
When the discharged sheets are accumulated on the first discharge tray 130 and the full notice sensor 24 is turned on as shown in FIG. 1B, the display lamp 31 is turned on in response thereto. Further, when sheets are accumulated on the first paper discharge tray 130 and the full sensor 25 is turned on as shown in FIG. 1C, the display lamp 31 is switched from lighting to blinking, and discharge of the subsequent sheets is stopped. When the user notices the blinking of the display lamp 31 and removes the sheet from the second paper discharge tray 130 and enters the state shown in FIG. 1A, the display lamp 31 is turned off. That is, if both the full notice sensor 24 and the full sensor 25 are turned off while sheets are stacked on the first paper discharge tray, the display lamp 31 is turned off, only the full notice sensor 24 is turned on, and the full sensor 25 is turned off. In the state of, the display lamp 31 is lit, and in the state where both the full notice sensor 24 and the full sensor 25 are on, the display lamp 31 is blinked. By controlling the display of the display lamp 31 as described above with respect to the states of the full notification sensor 24 and the full sensor 25, the user can be notified of the full notification and the full status.

  In FIG. 1, the second discharge tray 131 is retracted to the upper side in order to deposit discharged sheets on the first discharge tray 130. In this state, the full notice sensor 14 and the full sensor 15 cannot detect the accumulation state of the sheets, but the discharged sheets are not accumulated on the second discharge tray, so that the second discharge tray is moved to the position shown in FIG. The state when the tray is arranged at the sheet discharge position to the second paper discharge tray before moving may be displayed.

  On the other hand, when the second discharge tray is at the position shown in FIG. 2, if both the full notification sensor 14 and the full sensor 15 are off, the display lamp 32 is turned off, and only the full notification sensor 14 is turned on. The display lamp 32 is turned on when is full, and the display lamp 32 is blinked when both the full notice sensor 14 and the full sensor 15 are on. By controlling the display of the display lamp 32 as described above according to the states of the full notification sensor 14 and the full sensor 15, it is possible to notify the user of the full notification and the full state.

  One embodiment different from the above is shown in FIG. 7 and FIG. FIG. 7 shows a case in which the second paper discharge tray is moved close to the first paper discharge tray by a predetermined distance between sheet discharges periodically to detect the full notification sensor and the full sensor to perform multi-stage full notification detection. It is explanatory drawing which shows. FIG. 8B shows an example of a display unit in the case of performing a three-stage full notice and a full display.

  For example, as shown in FIG. 1A, when no sheets are stacked on the first paper discharge tray 130, the display lamp 31 turns off all four lamps. When the discharged sheets are accumulated on the first discharge tray 130, the second discharge tray is periodically lowered by a predetermined distance between sheet discharges, as shown in FIG. 7B or 7C. The state of the full notice sensor 24 and the full sensor 25 is detected at the position. When the sheet accumulates and the state shown in FIG. 7C is reached, only the first lamp from the bottom of the display lamps 31 is turned on. Further, when the sheets are accumulated and the state shown in FIG. 7B is reached, two lamps from the bottom among the display lamps 31 are turned on. When more sheets are accumulated, the full sensor 25 is turned on before reaching the predetermined position when the second discharge tray 131 is lowered to the predetermined position shown in FIG. 7B. As a lower limit, the second paper discharge tray 131 is not lowered further. However, since the user may remove the sheet while the sheet is being discharged, it is not necessary to periodically lower the tray. When the sheets are accumulated without being removed, the full notice sensor 24 is turned on with the second discharge tray 131 in the retracted position as shown in FIG. 7A. In this state, three lamps from the bottom among the display lamps 31 are turned on. When the full sensor 25 is turned on as shown in FIG. 1C, the uppermost lamp of the display lamp 31 is blinked and the subsequent sheet discharge is stopped. When the user notices the blinking of the display lamp 31 and removes the sheet from the second paper discharge tray 130 and enters the state of FIG. 1A, all the lamps of the display lamp 31 are turned off. That is, if both the full notice sensor 24 and the full sensor 25 are off at the position where the second paper discharge tray is lowered, all the display lamps 31 are turned off, and the second paper discharge tray 131 is at the position and only the full notice sensor 24 is in place. Is on and the full sensor 25 is off, the bottom lamp of the display lamps 31 is lit, and the full notice sensor 24 and the full sensor 25 are both on at the position where the second discharge tray is lowered. Two lamps are blinked from the bottom of the display lamp 31. Further, only the full notice sensor 24 is turned on when the second paper discharge tray is at the sheet discharge position, and when the full sensor 25 is off, the three lamps from the bottom among the display lamps 31 are turned on, and the second paper discharge tray is turned on. Is the position when the sheet is discharged, and when the full notice sensor 24 and the full sensor 25 are both on, the three lamps from the bottom of the display lamp 31 are turned on and the uppermost lamp is blinked. By controlling the display of the display lamp 31 as described above with respect to the states of the full notification sensor 24 and the full sensor 25, the user can be notified of the full notification and the full status.

  In the above description, only the case where the paper is discharged to the first paper discharge tray has been described for the sake of simplicity. However, when the discharged sheets are accumulated on the second paper discharge tray, the second paper discharge is performed. The tray is periodically lifted between sheet discharges and brought close to the upper deflection regulating member 13, and the states of the full notice sensor 14 and the full sensor 15 can be detected to perform multi-stage full notice detection. The display of the display lamp 32 can be controlled based on the detection result.

  In addition, when the upper limit or lower limit detection of the movable tray is also used by the full sensor or the full notice sensor as in the fourth embodiment, an abnormality when the movable tray is moved is displayed based on the detection of the full sensor or the full notice sensor. It may be. For example, if the full sensor or the full warning sensor that also serves as the lower limit sensor does not detect the lower limit even though the movable tray has been moved downward for a predetermined time, there may be an abnormality in the tray moving mechanism or sensor detection mechanism. . In this case, the movement of the movable tray may be stopped and an operation abnormality may be displayed on the display unit. Even when the upper limit detection of the movable tray is shared by the full sensor or the full warning sensor, the full sensor or full warning sensor that is also used as the upper limit sensor did not detect the upper limit even though the movable tray was moved upward for a predetermined time. In this case, the movement of the movable tray may be stopped and an operation abnormality may be displayed. The abnormal operation of the movable tray may be displayed on the operation unit for the user to operate the image forming apparatus.

(Embodiment 6)
Further, a sensor for detecting forgetting to take a sheet may be provided in the paper discharge tray, and display based on detection by the forgetting to take sheet may be performed. If there are sheets on the paper discharge tray that do not reach the full stacking height, it may be preferable to inform the user of this and completely remove the sheets.
For example, when the upper limit or lower limit of the movable tray is also used by the full sensor or the full warning sensor, it is preferable to completely remove the sheet in order to accurately determine the position of the movable tray in the fourth embodiment. As described in the above.

  However, there are other cases where it is preferable to prompt the user to remove the sheet from the paper discharge tray for the following reasons. In recent years, multifunction devices capable of performing a plurality of image reading / printing processes such as printers, copiers, and fax machines are increasing. As described above, such a multi-function peripheral has a “movable job separator” that branches and sorts the discharge tray according to the processing mode such as printer, copier, and fax. Of these, when operating as a copier, the user places a document on the platen of the machine, makes a copy, and takes the discharged sheet, so it is expected that the sheet will not be left in the discharge tray. . On the other hand, when operating as a printer, especially in a shared environment connected to a network, the user performs a printing operation at a host located away from the printer and picks up the discharged sheet when the printing is completed. Come to the printer. In such an environment, it is convenient if the user can know when the sheet is discharged. That is, in the case of a printer, the information that the user wants to know is not when a certain amount of sheets have been deposited on the paper discharge tray but when the printed sheet is output to the paper discharge tray. Therefore, it is preferable to provide a sensor on the paper discharge tray to inform the user that the first sheet has been discharged.

  Furthermore, when operating as a fax, it receives data sent at unspecified timing from an unspecified number of destinations. Since it is impossible to predict when the data will be sent, it is preferable to remove the sheet from the paper discharge tray at an early stage so that the full state can be avoided with a margin. For this reason, when there is even one sheet received in the paper discharge tray, it is preferable to inform the user and prompt the user to remove the sheet. Also, in order to receive the received data as soon as possible at the destination person, it is preferable to notify the reception if there is only one.

  In FIG. 1, a sheet removal forgetting sensor 26 is disposed on the first sheet discharge tray 130, and a sheet removal forgetting sensor 16 is disposed on the second sheet discharge tray. However, as described above, detection of forgetting to remove a sheet is particularly preferably provided in a printer other than copier or a paper discharge tray for fax. Therefore, for example, when the first paper discharge tray 130 is used for a copier and the second paper discharge tray is used for a printer and a fax machine, a sheet forgetting sensor may be provided only in the second paper discharge tray. FIG. 2 shows an example of such a configuration, where the second paper discharge tray 131 is provided with a sheet forgetting sensor 16, but the first paper discharge tray 130 is provided with a sheet forgetting sensor. It has not been.

It is explanatory drawing which shows the structural example of the sheet | seat deposition apparatus of this invention. (Embodiment 1) It is explanatory drawing which shows the different state of the sheet | seat deposition apparatus of this invention. (Embodiment 1) It is explanatory drawing which shows the structural example of the image forming apparatus of this invention. (Embodiment 1) It is explanatory drawing which shows the state of the sensor in the upper limit position and lower limit position in the case of detecting the upper limit and lower limit position of a 2nd discharge tray using a full notification sensor or a full sensor. (Embodiment 4) In the sheet deposition apparatus of this invention, it is explanatory drawing which shows the case where a sheet | seat presser arm has two bending parts. (Embodiment 2) In the sheet deposition apparatus of this invention, it is explanatory drawing which shows the case where a sheet | seat presser arm has a curved shape. (Embodiment 3) FIG. 6 is an explanatory diagram illustrating a case where a second discharge tray is periodically lowered by a predetermined distance between sheet discharges to detect the full notification sensor and the state of the full sensor to perform multi-stage full notification detection. (Embodiment 5) It is explanatory drawing which shows an example of the display part for notifying a user of the state of a paper discharge tray. (Embodiment 5)

Explanation of symbols

11, 21 Seat holding arms 12, 22 Arm support portions 13, 23 Deflection regulating portions 14, 17, 24, 27 Full warning sensor, second full warning sensors 15, 25 Full sensor 16, 26 Forgetting to take sensor 30 Display 31 , 32, 33, 34 Full notice / full indication lamp 101 Document table 102 Exposure light source 103 Reflective mirror 104 Imaging lens 105 Photoelectric conversion element, CCD
111 Photosensitive roller 112 Charging unit 113 Developing unit 114 Transfer charger 115 Fixing roller 116 Cleaning device 117 LSU
118 Developing roller 121 Main transport path 122 Sub transport path 123 Fixed paper feed cassette 124 Pickup roller 125 Registration roller 126 Guide member 127 Paper discharge port 128 Paper discharge roller 129 Carrying roller 130 First paper discharge tray 131 Second paper discharge tray

Claims (12)

A paper discharge tray for stacking sheets discharged from the sheet discharge unit;
At least a part of the sheet pressing arm having flexibility, a support end supported at one end by an arm support member disposed on the upper side of the sheet discharge unit, on the downstream side in the sheet discharge direction from the support end A free end that contacts the paper discharge tray or a sheet deposited on the paper discharge tray directly or via a contact member, and one or more bent portions that are formed between the support end and the free end. An arm having,
A deflection regulating portion that is arranged above the arm and regulates the upper limit position of each bending portion of the arm that rises while bending as the arm free end rises, and when the arm has a plurality of bending portions, as the free end rises A deflection regulating portion that sequentially regulates the upper limit from the bent portion on the support end side to the bent portion on the free end side;
A full warning sensor provided corresponding to each bent portion in order to detect that each bent portion is in a state regulated by the deflection regulating portion;
Full warning and full detection function, comprising a full sensor for detecting that the free end of the arm has reached the upper limit when the free end of the arm further rises from the state where the upper limit of all the bent portions is restricted Sheet stacking device. A paper discharge tray for stacking sheets discharged from the sheet discharge unit;
A sheet holding arm having flexibility, a support end supported at one end by an arm support member disposed above the sheet discharge portion, and a discharge tray or a discharge on the downstream side of the support end in the sheet discharge direction. An arm having a free end that contacts a sheet deposited on a paper tray directly or via a contact member, and a curved portion formed between the support end and the free end;
A deflection regulating portion that is disposed above the arm and regulates the upper limit position of the bending portion that rises while bending as the arm free end rises;
As the free end of the arm rises, a full notice sensor is provided corresponding to each point to detect a state in which one or more points of the bending portion are successively restricted from the support end point to the free end point. When,
Full notification and full detection characterized by comprising a full sensor for detecting that the free end has reached the upper limit when the free end of the arm further rises from the state in which all full notification sensors have detected the upper limit regulation state Functional sheet deposition equipment.   The contact member attached to the free end or the free end of the arm contacts the output tray when no sheets are deposited on the output tray, and accumulates on the top when sheets are accumulated on the output tray. The sheet deposition apparatus according to claim 1, wherein the sheet deposition apparatus is in contact with the formed sheet. The deflection regulating portion regulates the upper limit of the arm by the lower surface thereof coming into contact with each bending portion or bending portion of the arm,
3. The sheet stacking apparatus according to claim 1, wherein each full notification sensor is disposed on a surface of a deflection restricting portion where each point of each bent portion or curved portion of the arm contacts. A movable tray that moves up and down the output tray,
5. The sheet stacking apparatus according to claim 1, wherein either the full notification sensor or the full sensor functions to detect an upper limit of tray movement when the discharge tray is moved up and down. The paper discharge tray moves between a previous sheet discharge and a next sheet discharge to a second tray position that is elevated by a predetermined distance from the first tray position where sheets are accumulated, and a full notice sensor, a full sensor, or both After the detection by the sensor, return to the first tray position,
6. A sheet stacking apparatus according to claim 5, wherein the sheet stacking height on the sheet discharge tray is obtained based on detection results of the full notification sensor at the second tray position, the full sensor, or both. The deflection control part can move up and down,
The seat according to any one of claims 1 to 4, wherein either the full notification sensor or the full sensor functions to detect a lower limit of movement of the deflection regulating portion when the deflection regulating portion is moved up and down. Deposition equipment.   The deflection regulating unit moves between a previous sheet discharge and a next sheet discharge to a second position that is lowered by a predetermined distance from the first position for discharging the sheet, and a full notice sensor, a full sensor, or both sensors 8. After returning to the first position after the detection by the printer, the degree of sheet stacking height on the sheet discharge tray is obtained based on the detection results of the full notification sensor, the full sensor or both of them in the second position. Sheet deposition equipment.   The sheet stacking apparatus according to any one of claims 1 to 4, further comprising a sheet removal forgetting sensor that detects the presence or absence of a sheet in a region on which the sheet is stacked on the discharge tray. The sheet can be moved up and down, and the sheet is discharged to either the sheet stacking position where the sheet is stacked from the sheet discharging section below the sheet discharging section or the retreat position where the sheet is not stacked from the sheet discharging section above the sheet discharging section. Movable trays sometimes placed,
At least a part of the sheet pressing arm having flexibility, a support end supported at one end by an arm support member disposed on the upper side of the sheet discharge unit, on the downstream side in the sheet discharge direction from the support end A movable end or a free end that contacts a sheet deposited on the movable tray directly or via a contact member, and one or more bent portions formed upward between the support end and the free end. A first arm having;
A deflection regulating portion that is disposed above the first arm and regulates an upper limit position of each bent portion that rises as the first arm free end rises; and a first deflection regulating portion;
A movable tray full warning sensor provided corresponding to each bent portion of the first arm in order to detect that each bent portion of the first arm is in a state of being regulated by the first deflection regulating portion;
When the upper end of the bent portion of the first arm is restricted, when the free end of the first arm further rises, it is detected that the accumulated height of the accumulated sheet reaches the upper limit and the movable tray is full, and the movable type A movable tray full sensor that detects that the free end of the first arm has approached a predetermined distance from the first deflection regulating portion when the tray is moved up and down, and regulates the upper limit of the movable tray;
A fixed tray for depositing sheets discharged when the movable tray is in the retracted position;
At least a part of the sheet pressing arm having flexibility is supported at one end by an arm supporting member disposed on the lower surface of the movable tray, and is located downstream of the supporting end in the sheet discharging direction. A first end having a free end that contacts the fixed tray or a sheet deposited on the fixed tray directly or via a contact member, and one or more bent portions formed between the support end and the free end. Two arms,
A second deflection restricting portion that is disposed on the lower surface of the movable tray and restricts a limit position of a bent portion that approaches the movable tray as the second arm free end approaches the lower surface of the movable tray;
A fixed tray full warning sensor disposed on the lower surface of the movable tray in correspondence with the bent portion of the second arm in order to detect that the bent portion of the second arm is in a state of being restricted by the second deflection restricting portion; ,
Placed on the lower surface of the movable tray, and when the bent portion of the second arm is restricted, when the free end of the second arm approaches the lower surface of the movable tray, the stack height of the deposited sheet reaches the upper limit and is fixed When detecting that the tray is full and moving the movable tray up and down, the lower end of the movable tray is regulated by detecting that the free end of the second arm has approached a predetermined distance from the lower surface of the movable tray. A sheet stacking device with a full notice and a full detection function, comprising a fixed tray full sensor.   The sheet deposition apparatus according to claim 1, further comprising a display unit that displays information based on detection of the full notification sensor or the full sensor.   An image forming apparatus comprising the sheet deposition apparatus according to claim 1.

Images