JP2014091616A - Sheet discharge device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet discharge device and the like, which are capable of preventing occurrence of an accommodation failure on a stacking surface due to existence of a sheet resulting from a contact member appropriately swinging in accordance with the state of a sheet that is accommodated in an abnormal state as a result of a trail edge portion of the sheet in a discharge direction of the sheet floating from the stacking surface, causing detection of a sheet-full state, the contact member used for detecting a sheet-full state by swinging to a position corresponding to a stack height of sheets.SOLUTION: A sheet discharge device includes: a discharge part having a sheet discharge port and a pair of discharge rollers; an accommodation part having a stacking surface for accommodating a sheet; and a sheet-full detection part having a contact member and detection means for detecting a state where the contact member is swung to a position regarded a sheet-full state. Further, the contact member includes a second contact part that comes into contact with an upper surface of a sheet toward a trail edge of the sheet that is accommodated in an abnormal state and swings the contact member to a position regarded a sheet-full state when a height of the upper surface of the sheet toward the trail edge thereof reaches a height approaching a virtual line that is regarded a tangential line at a contact portion of the pair of discharge rollers as a discharge direction of the sheet.

Description

  The present invention relates to a paper discharge device and an image forming apparatus.

  For example, the following is known as a paper discharge device that discharges paper that has been subjected to processing such as image formation from the discharge port of the discharge unit and stacks it on the stacking surface of the storage unit.

In other words, the image forming unit includes a discharge unit having a paper discharge tray for storing paper to be discharged, and a full detection unit for detecting the fullness of the paper discharge tray, and the full detection unit has a full detection height adjusting unit. This is a paper discharge device of the apparatus (Patent Document 1).
According to Patent Document 1, according to this paper discharge device, an optimum full detection state can be obtained according to the properties and state of the curl of the paper to be used. When paper with almost no curl is used, the paper is full. Increasing the detection height and setting it near the paper exit allows you to increase the number of stacked sheets. Conversely, if you use paper with very large curls, set the full detection height low. It has been shown that it becomes possible to prevent the occurrence of a stack failure.

In addition, a sheet stacking unit on which sheets discharged from the discharge port are stacked, a fullness detection member capable of contacting the upper surface of the sheet stacked on the sheet stacking unit and detecting the full state of the sheet, A sheet pressing member capable of pressing a sheet discharged from the outlet from the upper surface, and the fullness detection member is in contact with a higher portion of the sheet stacking height of the detection member or the sheet pressing member The full state of the sheet is detected by any one of the positions, and the pressing of the sheet pressing member against the sheet is performed on the wide sheet wider than the narrow sheet rather than the narrow sheet having the narrow sheet width. This is a paper discharge device that is performed with a stronger force (Patent Document 2).
According to Patent Document 2, according to this paper discharge device, it is possible to appropriately detect the full state of a discharged sheet, and it is possible to change the pressing force on the sheet according to the sheet size. It has been shown to be.

JP 2003-137479 A JP 2005-96964 A

  According to the present invention, there is provided a contact member used for detecting a full state by contacting a sheet which is discharged from the discharge port and stored in a stacked state on a stacking surface and swings to a height corresponding to the stacking height. Even if paper is stored in an abnormal state with the rear part in the paper discharge direction floating on the stacking surface, the abnormal storage state is detected by swinging appropriately according to the state of the paper and being detected as full. Therefore, it is possible to provide a paper discharge device capable of preventing the occurrence of a storage failure on the stacking surface due to the presence of the paper, and an image forming apparatus including the paper discharge device.

The paper discharge device of this invention (A1)
A discharge unit having a paper discharge port and a pair of discharge rolls rotating in contact with each other so as to discharge the paper from the discharge port;
A storage unit having a stacking surface for storing the paper discharged from the discharge port of the discharge unit in a state of being dropped and stacked;
A contact member that contacts the upper surface of the sheet when discharged from the discharge port of the discharge unit and swings so as to be lifted to a position corresponding to the stacking height of the sheet stored in the stacking surface of the storage unit; A full detection unit having a detecting means for detecting a state when the contact member swings and continues to a position regarded as a full paper state,
The contact member of the fullness detection unit is in contact with the upper surface of the rear part of the paper that is stored in an abnormal state with the rear part in the paper discharge direction floating on the stacking surface of the storage unit, and the rear part of the paper When the height of the upper surface of the paper reaches a height close to a virtual line in which the tangent line at the contact portion of the discharge roll pair of the discharge portion is regarded as the paper discharge direction, the contact member is swung to a position where the contact member is considered to be full of paper. A second contact portion that allows
In addition, the paper discharge operation in the discharge unit is stopped when a full state of the paper is detected by the full detection unit.

The paper discharge device of the invention (A2) is the paper discharge device of the invention A1,
The second contact portion is in contact with the upper surface of the rear portion of the sheet stored in a normal state without the rear portion in the sheet discharge direction rising on the stacking surface of the storage portion of the contact member. A first contact portion that swings the contact member to a position that the sheet is considered to be full when the stacking height of the rear portion of the paper is full, and a support that is swingably supported by the contact member; Between the first contact portion and the support portion, and is provided in a state protruding from the straight line connecting the first contact portion and the support portion.

The paper discharge device of the present invention (A3) is the paper discharge device of the above invention A2,
The contact member is guided between the support portion and the second contact portion so that a front end portion of the paper when discharged from the discharge portion contacts and passes through the second contact portion. The guiding part is provided.

The paper discharge device of this invention (A4) is the paper discharge device of any one of the above inventions A1 to A3.
The stacking surface of the storage portion is formed on the upstream side in the paper discharge direction with a slope formed in a state of rising from the position below the discharge port in the gravity direction toward the downstream side in the paper discharge direction. A horizontal surface portion formed in a state extending substantially horizontally from the upper end of the slope portion to the downstream side in the paper discharge direction,
The second contact portion is configured to come into contact with the upper surface of the rear portion of the paper stored in an abnormal state by raising the rear portion in the paper discharge direction from the slope portion of the stacking surface. .

  The image forming apparatus according to the present invention (B1) is characterized by including any one of the paper discharge devices according to the aforementioned inventions A1 to A4.

  According to the paper discharge device of the invention A1, the paper discharged from the discharge port contacts the paper stored in a stacked state on the stacking surface and swings to a height corresponding to the stacking height to be used for detecting a full state. The contact member to be detected can be detected to be full by appropriately swinging according to the state of the paper, even if the paper is stored in an abnormal state with the rear portion of the paper discharge direction floating on the stacking surface. Thus, it is possible to prevent the occurrence of a storage failure on the stacking surface due to the presence of the sheet in the abnormal storage state.

  In the paper discharge device of the invention A2, the contact member having the second contact portion can be easily configured as compared with the case of not having the configuration of the invention, and the effect of the invention A1 can be similarly obtained. it can.

  Compared to the case of not having the configuration of the invention, the paper discharge device of the invention A3 is based on the invention A2 without obstructing the discharge of the sheet from the discharge port even if the contact member has the second contact portion. The effect can be obtained similarly.

  In the paper discharge device of the invention A4, compared with the case where the configuration of the invention is not provided, the presence of the paper stored in an abnormal state in which the rear portion of the paper discharge direction floats on the inclined surface of the stacking surface By appropriately swinging according to the state of a sheet in an abnormal storage state and being detected as a full state, it is possible to prevent a storage failure on the stacking surface due to the presence of the sheet.

  According to the image forming apparatus of the above-described invention B1, in the paper discharge device, the paper discharged from the discharge port contacts the paper stored in a stacked state on the stacking surface and swings to a height corresponding to the stacking height. The contact member used to detect the full state of the paper that is stored in an abnormal state with the rear part in the paper discharge direction floating on the stacking surface is appropriately swung according to the state of the paper. By detecting the state, it is possible to prevent the occurrence of a storage failure on the stacking surface due to the presence of the paper in the abnormal storage state, and to stably discharge and store the paper on which the image is formed. It becomes possible.

2 is a schematic explanatory diagram illustrating an internal configuration of an image forming apparatus including a paper discharge device according to Embodiment 1. FIG. FIG. 6 is a partial cross-sectional explanatory view showing a main part of the paper discharge device. FIG. 3 is an explanatory diagram illustrating an enlarged configuration (mainly a contact member) of a part of the paper discharge device of FIG. 2. FIG. 3 is an explanatory diagram showing an enlargement of a partial configuration (full detection unit) of the paper discharge device of FIG. 2. 5 is a flowchart showing control contents of a detection operation of a full paper state and a paper discharge operation. It is explanatory drawing which shows the operation state of the contact member of the full detection part with respect to the paper accommodated in a normal state. It is explanatory drawing which shows the operation state of the contact member of the full detection part with respect to the paper accommodated in an abnormal state. FIG. 10 is an explanatory diagram illustrating an operation state of a contact member of a full detection unit during a paper discharge operation. It is explanatory drawing which shows the malfunction of the full detection part with respect to the paper accommodated in the abnormal state in the conventional paper discharge apparatus.

[Embodiment 1]
1 and 2 show an image forming apparatus including a paper discharge device according to the first embodiment. FIG. 1 shows a main configuration of the image forming apparatus, and FIG. 2 shows a main part of the paper discharge apparatus.

<Configuration of image forming apparatus>
The image forming apparatus 1 is configured as a printer that forms a desired image on a sheet 19. Further, the image forming apparatus 1 has a structure in which a paper discharge device 5 that discharges and stacks the sheets 19 after the image is formed is arranged on the upper portion thereof. The paper discharge device 5 has a relationship constituting the upper part of the housing 10 of the image forming apparatus 1. Details of the paper discharge device 5 will be described later.

  The image forming apparatus 1 as a printer includes an image forming unit 2 that forms a toner image composed of toner as a developer in an internal space of a housing 10 and transfers the toner image to a sheet 19 as an example of a recording material. A paper feeding device 3 that houses and sends out the paper 19 supplied to the image forming unit 2 and a fixing device 4 that fixes the toner image formed by the image forming unit 2 to the paper 19 are mainly installed.

  The image forming unit 2 is configured by using, for example, a known electrophotographic system, and includes a photosensitive drum 21 that is rotationally driven in a direction indicated by an arrow A (counterclockwise direction in FIG. 1), and a photosensitive drum 21. A charging device 22 for charging the outer peripheral surface, which is an image forming region, to a required potential, and an electrostatic latent image having a potential difference by irradiating the outer peripheral surface of the charged photosensitive drum 21 with light based on required image information (signal). An exposure device 23 that forms an image, a developing device 24 that develops the electrostatic latent image with toner of a developer to form a toner image, a transfer device 25 that transfers the toner image from the photosensitive drum 21 to the paper 19, The cleaning device 26 mainly removes toner remaining on the surface of the photosensitive drum 21 after transfer and cleans it. Reference numeral 27 in FIG. 1 denotes a developer storage container for storing a developer to be replenished in the developing device 24, and reference numeral 28 denotes a developing device for supplying a required amount of developer for replenishment in the developer storage container 27 at a required time. 24 is a replenishing device to be transported to 24.

  The sheet feeding device 3 stores a plurality of sheets 19 of a required size and type used for image formation in a stacked state, and a sheet container 31 such as a tray type or a cassette type, and the sheet container. And a feeding device 32 that feeds the sheets 19 accommodated in the sheet 31 toward the conveyance path one by one. In a portion between the paper feeding device 3 of the housing 10 and the transfer position of the image forming unit 2 (between the photosensitive drum 11 and the transfer device 25), the paper 19 fed from the paper feeding device 3 is placed at the transfer position. A paper feed path 33 is provided to convey the paper. The paper feed path 33 is formed by a paper transport guide material, a pair of paper transport rolls 34a, 34b, and the like. The pair of paper transporting rolls 34 b is configured as a roll that adjusts the timing for feeding the paper 19 to the transfer position of the image forming unit 2.

  When the image forming unit 2 receives an image forming operation start command, the outer peripheral surface of the photosensitive drum 21 that starts rotating in the direction indicated by the arrow A is charged to a predetermined polarity and potential by the charging device 22 and then charged. The exposure device 23 performs exposure based on the image information on the outer peripheral surface of the photosensitive drum 21 to form an electrostatic latent image having a required potential. Subsequently, when the electrostatic latent image formed on the photosensitive drum 21 passes through the developing device 24, the electrostatic latent image is developed with toner charged to a required polarity supplied from the developing device 24 to form a toner image. Visualized. Subsequently, when the toner image formed on the photosensitive drum 21 is transported to the transfer position facing the transfer device 25 by the rotation of the photosensitive drum 21, the paper feed path from the paper feed device 3 is synchronized with the image forming timing. The image is electrostatically transferred by the transfer device 25 to the sheet 19 fed through the sheet 33.

  The fixing device 4 is held in a casing (not shown) in which an introduction port and a discharge port through which the sheet 19 is formed are heated to a required temperature by a heating unit and is rotated in a required direction. A heating rotator 41 such as a roll form and a belt form, and a pressure rotator 42 such as a roll form and a belt form that are driven to rotate in contact with a required pressure so as to substantially follow the axial direction of the heating rotator 41. Is arranged. The fixing device 4 introduces and passes the paper 19 after the toner image has been transferred to a contact portion (fixing processing portion) formed by the heating rotator 41 and the pressure rotator 42 contacting each other. Thus, a fixing process (heating and pressing) is performed.

  In this image forming apparatus 1, the sheet 19 after transfer sent from the image forming unit 2 is directed to the fixing device 4 at a portion between the fixing device 4 of the housing 10 and the transfer position of the image forming unit 2. An intermediate conveyance path 43 is provided for conveyance. Further, the sheet 19 after fixing sent from the fixing device 4 is fed to the portion between the fixing device 4 and the paper discharge device 5 (the discharge portion 51) of the housing 10. ) Is provided in the discharge path 44. Further, at a portion between the discharge path 44 and the paper feed path 33, the sheet 19 on which one side is formed and discharged through the discharge path 44 is fed to the paper feed path 33 with its front and back surfaces reversed. A reverse retransmission path 46 for retransmission is provided. The reverse retransmission path 46 is configured by arranging a sheet conveyance guide material, a conveyance destination switching claw, a sheet conveyance roll pair 47, and the like.

  The paper 19 on which the image is formed is conveyed to the paper discharge device 5 (the discharge unit 51) through the discharge path 44 and then stored in a stacked state in the paper discharge device 5 (the storage unit 55).

<Configuration of paper discharge device>
Next, the paper discharge device 5 will be described.

  As shown in FIGS. 1, 2, and the like, the paper discharge device 5 includes a discharge unit 51 that discharges the paper 19 after the image is formed, and a storage unit that stores the discharged paper 19 in a stacked state. 55 and a full detection unit 57 that detects that the paper 19 stored in the storage unit 55 is full.

  The discharge unit 51 includes a casing that constitutes a part of the upper portion of the casing 10 (exterior member), and a discharge port 52 that discharges the sheet 19 to be discharged formed in a part of the casing, This is a component that is installed inside the housing and has at least a discharge roll pair 53 including a pair of discharge rolls 53A and 53B that rotate in contact with each other so as to discharge the sheet 19 to be discharged from the discharge port 52.

  The discharge port 52 is formed to have an elongated rectangular opening shape along the horizontal direction. The discharge roll pair 53 is disposed at the terminal position of the discharge path 44 described above, and is spaced apart from the two rotary shafts 53c and 53d that are arranged to extend in parallel along the longitudinal direction of the discharge port 52. Several are attached. Further, the discharge roll pair 53 is rotationally driven in a required direction by, for example, one of the discharge rolls 53 </ b> A (the rotation shaft 53 c that fixes the discharge roll 53 </ b> A) receiving rotational power from the drive motor 54. Further, the discharge unit 51 is provided with a discharge detection sensor (not shown) that detects a state after the discharged paper 19 reaches the discharge roll pair 53 (between) and is discharged.

  The accommodating portion 55 includes a casing constituting another part of the upper portion of the casing 10, and the sheets 19 discharged from the discharge port 52 of the discharge portion 51 are dropped and stacked on a portion of the casing. This is a component provided with a loading surface 56 that is accommodated in a closed state.

  The stacking surface 56 according to the first embodiment is formed in a state of an upward gradient from a position on the upstream side in the paper discharge direction B to a downstream side in the paper discharge direction B from a position below the discharge port 52 in the gravity direction G. 56A, and a horizontal plane portion 56B formed in a state extending substantially horizontally from the upper end of the slope portion 56A to the downstream side in the paper discharge direction B. For this reason, an end for contacting the upstream end in the discharge direction B of the stored paper 16 to a portion from the lower end of the slope portion 56A to the lower position of the discharge roll pair 53 is brought into contact with the storage portion 55 and stopped. A part contact surface part 56C is provided. Further, the horizontal surface portion 56B of the loading surface 56 is formed in a state where the height of the surface is the same height as the lower discharge roll 53B of the discharge roll pair 53 or slightly lower than that.

  The fullness detection unit 57 contacts the upper surface of the sheet 19 when discharged from the discharge port 52 of the discharge unit 51 and reaches a position corresponding to the stacking height h of the sheet 19 stored on the stacking surface 56 of the storage unit 55. It is a component having at least a contact member 60 that swings so as to be lifted, and detection means 67 that detects a state when the contact member 58 swings and continues to a position where it is determined that the sheet 19 is full.

  As shown in FIG. 3 and the like, the contact member 60 is configured by a plate-like member, and is disposed at a predetermined position in the longitudinal direction of the discharge port 52 (for example, on all the upper surfaces of the various sheets 19 to be discharged). At a position where they can come into contact with each other, for example, the support shaft 61 at a height substantially corresponding to the upper portion of the upper discharge roll 53A of the discharge roll pair 53 is mounted so as to swing in the directions indicated by arrows C1 and C2. . Incidentally, the contact member 60 is not in contact with the upper surface of the sheet 19 accommodated in the stacking surface 56 and when the sheet 19 is not discharged from the discharge unit 51 (in a free state). As shown in FIG. 3 and FIG. 6 (contact member 60 indicated by a two-dot chain line), etc., it is attached so as to be kept stationary in a predetermined posture (a state where no more swings in the direction of arrow C2). Yes.

  Further, as shown in FIG. 6, the contact member 60 is disposed in the discharge direction B of the sheet 19 at the tip end of the free end where the contact member 60 is farthest from the support shaft 61 and approaches the stacking surface 56 (the inclined surface portion 56A). The first contact portion 62 that can contact the upper surface of the rear portion 19a of the sheet 19 (K) that is accommodated in a normal state without the rear portion 19a being lifted extremely from the loading surface 56 (the slope portion 56A) is formed. It has a shape. The first contact portion 62 is not in contact with the stacking surface 56 (the inclined surface portion 56A), but is in a state of being closest to the stacking surface 56, and the stacking height h of the sheets 19 accommodated in the stacking surface 56. Is configured to come into contact with the upper surface of the (uppermost) sheet 19 only when the required height hm is reached (FIG. 3).

  The detecting means 67 detects that the contact member 60 has swung to a position considered to be full of paper, for example, a light emitting part that emits light and a light receiving part that receives the light at a certain distance. An optical detection sensor is applied.

  In this case, as illustrated in FIG. 4, the detection means 67 has a part of the contact member 60 when it is swung more than a certain angle between the light emitting portion and the light receiving portion (gap) of the optical detection sensor. And installed so that a state of blocking the light beam between the light emitting unit and the light receiving unit occurs. Then, only a predetermined angle (swing angle from the stationary position when not accommodated) θx required until the contact member 60 reaches a position where the sheet is considered to be full (the stacking height h is the full height hx: FIG. 6). When swinging, a part of the contact member 60 enters between the light emitting part and the light receiving part and blocks the light beam between the light emitting part and the light receiving part, thereby detecting the swinging state of the contact member 60. Configured to be. Here, a part of the contact member 60 is a part of the main body in the first embodiment. In addition, as a part of this contact member 60, it is also possible to set it as the to-be-detected part 66B which fixes and provides in the state protruded from a part of main body so that it may illustrate in FIG. In this case, the detected portion 66B can be provided on a part of the support shaft 61 to which the contact member 60 is fixed, in addition to being provided integrally with the main body of the contact member 60. Further, the detecting means 67B for detecting the detected portion 66B may be arranged at a position where the detected portion 66B in the required state can be reliably detected.

  In the paper discharge device 5, a drive motor 54 that rotates the discharge roll pair 53 of the discharge unit 51 is connected to, for example, the control unit 70 of the image forming apparatus 1, and the operation of the drive motor 54 is controlled. It is like that. Further, the detection means 57 of the fullness detection unit 57 is also connected to the control means 70 of the image forming apparatus 1 and transmits the detection information of the detection means 57.

  The control means 70 controls the drive motor 54 of the discharge unit 51 to start and stop the discharge roll pair 53. In addition, the control unit 70 obtains detection information from the detection unit 57 of the full detection unit 57, determines whether or not the paper 19 stored on the stacking surface 56 of the storage unit 55 is full, and is in a full state. When this is detected, the drive motor 54 of the discharge unit 51 is controlled to stop the drive of the discharge roll pair 53.

  The detection (determination) of the paper full state by the control means 70 is configured to be performed, for example, according to the procedure illustrated in FIG.

  That is, the control means 70 determines whether or not it is detected by the paper discharge sensor (not shown) that detects that the image forming operation has been executed and the paper discharge operation has been completed (step 10: hereinafter, This is simply displayed as “S10”.) When the paper discharge detection information by the paper discharge sensor is obtained, the timer starts and starts measuring the elapsed time t (S11). Thereafter, the output information from the detection means 57 of the full detection unit 57 is monitored (S12). If there is output information indicating that the detection of the swing of the contact member 60 has been completed, the contact member 60 is indicated by the arrow C2. Since the sheet 19 on the stacking surface 56 is not full, the timer is reset (S13), and then the sheet 19 is discharged by the sheet discharge operation discharge unit 51. The operation is allowed to continue (S14).

  If the swing of the contact member 60 is not detected in step S12, it is determined whether or not the elapsed time t is equal to or longer than a preset threshold time Tn (S15), and when the threshold time Tn is not exceeded. Return to step S12. On the other hand, when the time is equal to or longer than the threshold time Tn in step S15, the timer is reset (S16), and it is determined that the paper 19 on the stacking surface 56 is full (S17). Is forcibly stopped (S18). As the threshold time Tn at this time, for example, a time required for making an accurate determination is added to the time required for the discharge operation of one sheet 19 by the discharge roll pair 53 of the discharge unit 51 (discharge required time). Time applies. As a result, a part of the sheet 19 previously stored in the full state on the stacking surface 56 is pushed and shifted so that the storage state (position and orientation) is disturbed or the sheet 19 is stored first. It is possible to prevent a housing failure such as a part of the sheet 19 being pushed out of the stacking surface 56 and dropped.

  In the paper discharge device 5, as shown in FIG. 6, when the paper 19 (K) is accommodated in a normal state with the rear portion 19a of the paper hardly rising with respect to the stacking surface 56. The contact member 60 in the full detection unit 57 operates as follows.

  First, when the sheet 19 after the image is formed is discharged from the discharge port 52 of the discharge unit 51, the upper surface of the front portion in the discharge direction B of the sheet is discharged in contact with the contact member 60. 60 swings so as to be temporarily lifted in the direction indicated by arrow D1. Subsequently, when the discharged paper 19 is released from the discharge action of the discharge roll pair 53, it is naturally dropped and accommodated by its own weight toward the stacking surface 56. At this time, the contact member temporarily lifted 60 also has no swinging action due to the paper 19, and swings so as to descend in the direction indicated by the arrow D2 due to its own weight and returns to a stationary state (state indicated by a two-dot chain line in FIG. 6).

  After that, when a plurality of sheets 19 are stored in a stacked state on the stacking surface 51 and stored until the stacking height h reaches the predetermined height hm (FIG. 3), the stored sheets 19 are stored. The first contact portion 62 of the contact member 60 comes into contact with the uppermost upper surface. Thereafter, when the sheets 19 are successively stacked and stored on the stacking surface 51, the contact member 60 is swung so as to be gradually lifted in the direction indicated by the arrow D1 according to the stacking height h of the sheets 10 at that time. Move. When the stacking height h reaches the full height hx, as shown in FIG. 6, the contact member 60 is swung to a position (P1) where the sheet is considered to be full. As a result, the contact member 60 is detected by the detection means 67 to be full (FIG. 4).

  Thus, in the paper discharge device 5, the paper discharge operation by the discharge roll pair 53 of the discharge unit 51 is forcibly stopped (FIG. 5). For this reason, in the paper discharge device 5, the paper 19 is continuously discharged and stored on the stacking surface 56 on which the paper 19 (K) stored in a normal state exists. Therefore, it is possible to prevent the storage failure of the sheet 19 (K) previously stored by the sheet 19 discharged subsequently.

  Here, when a substantially straight rod-shaped contact member 600 as exemplified in FIG. 9 is applied as a contact member of the full detection unit in the conventional paper discharge device, the following problems occur.

  First, the contact member 600 is swingably attached to the support shaft 61, and the tip 620 at the free end thereof is one contact that can come into contact with the upper surface of the (uppermost) sheet 19 accommodated in the stacking surface 56. It is comprised as a part.

  Then, the sheet 19 (K) that is accommodated in a normal state without the rear portion 19 a of the sheet 19 in the discharge direction B of the sheet 19 being lifted from the stacking surface 56 (the inclined surface portion 56 A) thereof with respect to the stacking surface 56 is stacked. When loaded and accommodated until the height h reaches the full height hx, the contact member 600 is positioned so that the contact portion 620 comes into contact with the rear portion 19a of the sheet 19 (K) and is considered to be full (P1). It is swung so that it can be lifted up. As a result, it is correctly detected that the full detection unit is full.

  On the other hand, as illustrated in FIG. 9, with respect to the stacking surface 56, the rear portion 19 a of the sheet 19 in the discharge direction B is lifted from the stacking surface 56 (the inclined surface portion 56 </ b> A) and is stored in an abnormal state. The height of the upper surface (of the uppermost sheet) of the side portion 19a is close to a virtual line (an alternate long and short dash line with an arrow) in which the tangent at the contact portion 53e of the discharge roll pair 53 is regarded as the sheet discharge direction B. Thus, when the paper 19 (W) is received, the operation is as follows.

  That is, the contact member 600 at this time may not swing so that the contact portion 620 contacts the rear portion 19a of the sheet 19 (W) but is lifted up to a position (P1) that is regarded as being full. . In this case, the full detection unit does not detect that the full state has been reached. As a result, when the discharge operation of the sheet 19 and its accommodation are continued on the stacking surface 56 on which the sheet 19 (W) accommodated in the abnormal state exists, the subsequent operation is continued. There may be a case where the storage of the paper 19 (W) previously stored by the discharged paper 19 occurs. Further, when the rear portion 19a of the sheet 19 (W) stored in an abnormal state is stored in a state where the discharge port 52 is blocked, the sheet 19 discharged subsequently may cause a discharge failure. There is also. As the sheet 19 (W) stored in such an abnormal state, for example, a sheet that is stiff (difficult to bend) or a sheet in which the rear portion is curled (curved upward or downward) is used. is there.

<Detailed configuration of paper discharge device>
Therefore, in the paper discharge device 5, as the contact member 60 of the fullness detection unit 57, in addition to the first contact unit 62 described above, a member having a second contact unit 63 described in detail below is adopted. Yes.

  As shown in FIG. 3, FIG. 7 and the like, the contact member 60 is a sheet 19 (abnormally housed in an abnormal state in which the rear portion 19a in the sheet discharge direction B is lifted on the stacking surface 56 (the inclined surface portion 56A). W) is an imaginary line that is in contact with the upper surface of the rear portion 19a of the sheet 19 (W) and that the height of the upper surface of the rear portion 19a of the sheet 19 (W) is regarded as the sheet discharge direction B. A second contact portion 63 is formed that swings the contact member 60 to a position (P1) where the contact member 60 is considered to be full of paper when the height approaches a dash-dotted line with an arrow.

  The abnormal state in which the rear portion 19a in the paper discharge direction B is lifted up is an imaginary line (dotted line with arrows) indicating the paper discharge direction B when the height of the upper surface of the rear portion 19a of the paper is in the accommodated state. In addition to this, the height of the rear portion 19a of the uppermost sheet is increased as a result of stacking a plurality of sheets in which the rear portion 19 is curled, for example. It also includes a state where it floats until it approaches a virtual line indicating the paper discharge direction B. The tangent line at the contact portion 53e of the discharge roll pair 53 is a straight line orthogonal to the straight line L1 connecting the centers of the rotation shafts 53c and 53d of the pair of discharge rolls 53A and 53B. Furthermore, when the height of the upper surface of the rear portion 19a of the paper 19 (W) approaches a virtual line (arrowed line with arrows) indicating the paper discharge direction B, the height of the upper surface is in contact with the virtual line. However, there is a possibility that the sheet 19 (W) that is discharged after the sheet 19 comes into contact with the sheet 19 and that the sheet 19 (W) that has been previously stored is inadequate.

  As shown in FIG. 3 and the like, the second contact portion 63 in the first embodiment exists between the first contact portion 62 and the support portion of the portion supported by the support shaft 61. This is a portion provided in a state protruding from the straight line (dashed line) L2 connecting the first contact portion 62 and the support portion to the side where contact with the paper 19 is possible. In the first embodiment, the second contact portion 63 is arranged at a portion corresponding to the apex of the triangle with the straight line L2 connecting the first contact portion 62 and the support portion as the base. Further, the second contact portion 63 is formed on the upper surface of the sheet 19 (W) accommodated in the abnormal state when, for example, the first contact portion 62 is at a position (P1) regarded as a sheet full state. It is formed (placed) at a position where it comes into contact.

  Further, the contact member 60 is disposed between the support portion of the portion supported by the support shaft 61 and the second contact portion 62, and the leading end portion 19s of the sheet 19 when discharged from the discharge portion 51 (FIG. 8). Is provided so that the guide part 64 is guided so as to pass through the second contact part 63 and advance.

  As shown in FIG. 3 and the like, the guide portion 64 in the first embodiment has a linear shape connecting the support portion and the second contact portion 62, and the contact member 60 is in a stationary state. And a shape extending in a direction substantially perpendicular to the paper discharge direction B (a dashed line with arrows) while facing the contact portion 53e of the discharge roll pair 53. In the contact member 60, a portion 65 between the first contact portion 62 and the second contact portion 63 is formed in a curved shape curved inward as shown in FIG.

  In the paper discharge device 5, as shown in FIG. 7, the rear portion 19 a is lifted with respect to the stacking surface 56, and the height of the upper surface of the rear portion 19 a is the paper discharge of the discharge roll pair 53. When the sheet 19 (W) is received in an abnormal state where the height approaches the imaginary line indicating the direction B, the contact member 60 in the full detection unit 57 operates as follows.

  That is, the contact member 60 has a second contact located on the side closer to the sheet 19 than the first contact portion 62 with respect to the rear portion 19a of the sheet 19 (W) accommodated in the abnormal state. The part 63 preferentially contacts and swings so as to be lifted in the direction indicated by the arrow D1, and further swings to a position (P1) that is finally regarded as a sheet full state due to the contact of the second contact part 63. Be moved. As a result, the contact member 60 is detected by the detection means 67 to be full (FIG. 4). Thus, in the paper discharge device 5, the paper discharge operation by the discharge roll pair 53 of the discharge unit 51 is forcibly stopped (FIG. 5).

  Therefore, in the paper discharge device 5, the paper 19 is continuously discharged and stored on the stacking surface 56 on which the paper 19 (W) stored in an abnormal state exists. Therefore, it is possible to prevent the sheet 19 (W) that has been previously stored by the sheet 19 that is subsequently discharged from being poorly stored.

  In this case, if the user removes the sheet 19 (W) stored in an abnormal state from the stacking surface 56, the contact member 60 swings so as to descend in the direction indicated by the arrow D2, and the full detection unit 57 The detection by the detection means 57 is also completed, and the control for forcibly stopping the paper discharge operation is released. Even if the sheet 19 (C) is stored in an abnormal state with the rear portion 19a floating, the height of the upper surface of the rear portion of the sheet 19 (C) is illustrated as illustrated by a two-dot chain line in FIG. When the height is at a height that is not close to the virtual line indicating the paper discharge direction B of the discharge roll pair 53 and is away from the virtual line, the second contact portion 63 of the contact member 60 does not contact, or Even if the second contact portion 63 comes into contact, the second contact portion 63 cannot be swung to the position (P1) where the contact member 60 is considered to be full.

  Further, in the paper discharge device 5, when the contact member 60 is in a stationary state as shown by a two-dot chain line in FIG. 8, the second contact portion 63 in the contact member 60 is discharged from the discharge port 52 and the discharge roll pair 53. A situation occurs in which the path in the direction B is blocked, which may hinder the discharge operation of the sheet 19. However, since the contact member 60 is provided with the guide portion 64 between the support portion and the second contact portion 63, the leading end of the sheet 19 discharged through the discharge port 52 by the discharge roll pair 53. The portion 19s acts to abut against the guide portion 64 and push the contact member 60.

  Thereby, the contact member 60 starts to swing easily so as to be efficiently pushed by the discharged paper 19 and lifted in the direction indicated by the arrow D1. In addition, since the guiding portion 64 is changed to a state of obliquely intersecting the paper discharge direction B when the contact member 60 starts to swing, the leading end portion 19s of the paper 19 also passes through the second contact portion 53 by the guiding portion 64. You will be guided to go smoothly. As a result, even the contact member 60 having the second contact portion 63 functions satisfactorily without hindering the discharge of the sheet 19 from the discharge port 52.

  During the discharging operation of the sheet 19, the contact member 60 is swung to a height position that has passed the position (P1) that is temporarily regarded as a sheet full state as shown by a solid line in FIG. It will be lifted high. Incidentally, since the contact member 60 swings so as to be temporarily lifted high as described above during the paper discharge operation, the contact member 60 is swung to a position (P1) regarded as being full of paper and detected. It will be detected by means 67. However, when the sheet 19 discharged at this time is released from the discharging action from the discharge roll pair 53, it naturally falls by its own weight toward the stacking surface 56, so that the contact member 60 that has been lifted high is also arrowed by its own weight. It swings so as to descend in the direction indicated by D2, and finally returns to a stationary state. Thereby, the detection time t by the detection means 57 of the contact member 60 does not exceed the normal required time for paper discharge and does not eventually exceed the threshold time Tn. For this reason, even if the contact member 60 swings in a state of being lifted high during the paper discharging operation, it is not detected that the contact member 60 is full (FIG. 5).

[Other embodiments]
In the first exemplary embodiment, the case where the paper discharge device 5 is applied to an image forming apparatus that forms an image composed of a developer is exemplified. However, such a paper discharge device employs other image forming methods. The present invention can be applied to an image forming apparatus, or can be applied as a paper discharge device in a device in another field where a plurality of sheets need to be discharged and stored in a stacked state.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 5 ... Paper discharge apparatus 19 ... Paper 19a ... Back part 19 (K) ... Paper 19 (W) accommodated in a normal state ... Paper 51 accommodated in an abnormal state ... Discharge part 52 ... Discharge Exit 53 ... Discharge roll pair 55 ... Accommodating portion 56 ... Loading surface 56A ... Slope portion 56B ... Horizontal surface portion 57 ... Full detector 60 ... Contact member 64 ... Guide portion 67 ... Detection means B ... Paper discharge direction C1, C2 ... Shaking Direction of movement h ... Loading height P1 ... Position regarded as full

Claims (5)

A discharge unit having a paper discharge port and a pair of discharge rolls rotating in contact with each other so as to discharge the paper from the discharge port;
A storage unit having a stacking surface for storing the paper discharged from the discharge port of the discharge unit in a state of being dropped and stacked;
A contact member that contacts the upper surface of the sheet when discharged from the discharge port of the discharge unit and swings so as to be lifted to a position corresponding to the stacking height of the sheet stored in the stacking surface of the storage unit; A full detection unit having a detecting means for detecting a state when the contact member swings and continues to a position regarded as a full paper state,
The contact member of the fullness detection unit is in contact with the upper surface of the rear part of the paper that is stored in an abnormal state with the rear part in the paper discharge direction floating on the stacking surface of the storage unit, and the rear part of the paper When the height of the upper surface of the paper reaches a height close to a virtual line in which the tangent line at the contact portion of the discharge roll pair of the discharge portion is regarded as the paper discharge direction, the contact member is swung to a position where the contact member is considered to be full of paper. A second contact portion that allows
The paper discharge operation of the paper discharge unit is stopped when the full state detection unit detects a paper full state. The second contact portion is in contact with the upper surface of the rear portion of the sheet stored in a normal state without the rear portion in the sheet discharge direction rising on the stacking surface of the storage portion of the contact member. A first contact portion that swings the contact member to a position that the sheet is considered to be full when the stacking height of the rear portion of the paper is full, and a support that is swingably supported by the contact member; Exists between the department and
The paper discharge device according to claim 1, wherein the paper discharge device is provided so as to protrude from a straight line connecting the first contact portion and the support portion to a side capable of contacting the paper.   The contact member is guided between the support portion and the second contact portion so that a front end portion of the paper when discharged from the discharge portion contacts and passes through the second contact portion. The paper discharge device according to claim 2, further comprising a guiding portion to be moved. The stacking surface of the storage portion is a slope portion formed in an upwardly inclined state from a position lower in the gravitational direction than the discharge port on the upstream side in the paper discharge direction toward the downstream side in the paper discharge direction, A horizontal plane portion formed in a state extending substantially horizontally downstream from the upper end of the slope portion in the paper discharge direction,
2. The second contact portion is configured to be able to come into contact with an upper surface of a rear portion of a sheet stored in an abnormal state by raising a rear portion in the sheet discharge direction from the inclined surface portion of the stacking surface. The paper discharge device according to any one of 1 to 3.   An image forming apparatus comprising the paper discharge device according to claim 1.

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