JP2011016652A - Sheet postprocessing apparatus and image forming system having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet postprocessing apparatus without causing inconvenience such as end folding at the same time, without overrunning the sheet end from a stopper position, when butting and aligning a sheet against and by a regulating stopper.SOLUTION: A sheet transfer means 35 for transferring the sheets toward a stopper means 30 and an aligning means 40 are arranged upstream of the stopper means 30 above a processing tray 28 for stacking sheets from a sheet discharge outlet 24. The aligning means 40 is constituted of a frictional rotating body 40v for transferring the sheet, an end guide member 41 guiding the sheet end and a rocking member 43 rockably supporting these. The rocking rotational center 42o of the rocking member 43 is arranged at the position of reducing pressure contact force between the frictional rotating body 40v and the sheets by raising-up force of the sheet acting on the guide member 41.

Description

  The present invention relates to a sheet post-processing apparatus that performs post-processing such as paper binding on a sheet transported from an image forming apparatus such as a copying machine or a printer, and aligns the sheet transported on a tray from a paper discharge port to a predetermined position. The present invention relates to an improvement of a sheet alignment mechanism.

  In general, this type of sheet post-processing apparatus is provided with a processing tray at a paper discharge port of an image forming apparatus such as a copying machine or a printer, and a post-processing apparatus such as a stapler device, a punch device, or a stamp device is provided on the processing tray. It is widely known as an apparatus that performs post-processing by aligning and stacking sheets sent from an image forming apparatus.

  Conventionally, in such an apparatus, a processing tray is disposed downstream of the sheet discharge outlet, a stack tray is disposed downstream of the processing tray, and a sheet (bundle) post-processed by the processing tray is stored in the stack tray. Are known. For example, in Patent Document 1, a processing tray is disposed on the downstream side of the sheet discharge outlet and a processing tray is disposed on the downstream side. A structure is disclosed in which the front end portion is supported by a stack tray and the rear end portion of the sheet is supported by a processing tray (bridge support).

  In such an apparatus, it is necessary to dispose a sheet alignment mechanism for aligning a sheet carried out from the sheet discharge outlet to a predetermined restriction position in a state where the sheet is bridge-supported between the two trays. For this reason, the apparatus of Patent Document 1 discloses a feeding mechanism for abutting and aligning a sheet sent from a paper discharge port on a processing tray against a regulating stopper. In this document, a sheet discharge belt is suspended from a sheet discharge port, and the sheet end is conveyed to a regulation stopper by this belt.

  Further, as a similar mechanism, for example, Patent Document 2 discloses that a sheet is pressed by a pressing guide when the sheet carried on the tray is abutted and aligned with the restriction stopper. In this document, when a sheet transported from a paper discharge port onto a tray is sent to a restriction stopper by a paper discharge means (ring-shaped belt member), a conveyance guide plate having a trap shape is provided between the paper discharge means and the restriction stopper. Is provided.

JP 2006-248686 A Japanese Patent No. 3673694

  As described above, when the sheet from the sheet discharge outlet is abutted and aligned with the restriction stopper disposed at a predetermined position on the tray, conventionally, a conveyance rotating body that transfers the sheet to the stopper along the tray, and a sheet leading end are arranged. It is already known to arrange a sheet guide for guiding the stopper.

  However, in a recent image forming apparatus, the following problems occur in the conventional alignment mechanism because of the use of a sheet having a wide range of properties. FIG. 11 shows a model of a conventional alignment mechanism, and a sheet conveyed from the sheet discharge outlet 100 onto the tray 101 is transferred to the restriction stopper 103 by a ring belt (aligning belt) 102. At this time, a guide plate 104 is disposed between the belt 102 and the regulating stopper 103 to prevent the sheet with the trailing edge curled from approaching the stopper 103. In such a structure, when the front end (or rear end) of the sheet is curled upward, the end of the sheet rises and is guided by the guide plate 104 and locked in a normal posture without getting over the stopper.

  However, when the sheet discharge roller 105 disposed on the upstream side of the belt 102 is overrun (excessive conveyance) as shown in the figure, the trailing edge of the sheet is curved and deformed in a loop shape as indicated by a chain line in the figure. At this time, the ring belt 102 continues to rotate in the paper discharge direction (counterclockwise in the figure). Therefore, the trailing edge of the sheet that has been curved and deformed in a loop shape due to excessive conveyance of the paper discharge roller 105 is curved and deformed in a loop shape (chain line) from above. At this time, the leading edge of the sheet is pressed from above by the guide plate 102. As a result, problems such as broken tips and wrinkles occur. Such problems are widespread in the use of sheets from thick paper to thin paper, and image forming conditions are complicated, such as color printing and double-sided printing. For this reason, it is difficult to prevent the previous overrun by controlling the sheet conveyance.

  For example, the coefficient of friction is greatly different between a sheet of double-sided color printing for thick paper and a sheet of monochrome printing for single-sided monochrome printing, and it is difficult to accurately control the position of the sheet conveyance. Therefore, it is difficult to control the conveyance so that the sheet is not excessively conveyed with respect to the restriction stopper and is not unreached at the same time.

  The present inventor has investigated the cause of problems such as sheet sheet folding and wrinkling shown in FIG. This requires a mechanism in which the conveyance belt and the conveyance guide both move up and down according to the sheet stacking amount on the tray. Conventionally, since these elevating mechanisms are individually configured, attention is paid to the fact that the sheet conveying force overrunning the conveying belt and the sheet lifting force acting on the conveying guide are inconsistent with each other. In other words, even if the belt overrun progresses and a sheet lifting force is generated in the conveyance guide, the belt continues to feed the sheet without weakening the force, which causes the sheet to be bent, uneven distortion, wrinkles, etc. It came to investigate that it was causing the malfunction of.

  Therefore, the present inventor applies a conveying belt to the sheet according to the pushing force (following force) when a lifting force (pushing force) is applied from the sheet to the conveying guide after the leading edge of the sheet hits the regulation stopper. It came to the idea of reducing the conveying power. As a result, even if an excessive conveying force acts on the sheet that hits the restriction stopper, it is possible to solve problems such as bending of the leading edge.

The main object of the present invention is to provide a sheet post-processing apparatus that does not cause the sheet tip to overrun from the stopper position at the time of abutting and aligning the sheet with the regulating stopper, and at the same time, does not cause problems such as tip breakage. It is said.
A further object of the present invention is to provide this possible stopper mechanism for orderly aligning the sheet leading edge at a low cost with a simple structure.

  In order to achieve the above object, the present invention provides a sheet transfer means for transferring a sheet toward the stopper means, and an aligning means on the upstream side of the stopper means, above the processing tray for collecting sheets from the sheet discharge outlet. To do. The aligning means includes a friction rotator for transferring the sheet, a tip guide member for guiding the leading end of the sheet, and a swinging member for swingably supporting them, and the swinging rotation of the swinging member. The center is arranged at a position where the pressing force between the friction rotating body and the sheet is reduced by the lifting force of the sheet acting on the guide member.

  The action is described in detail below. A discharge tray (24), a processing tray means (28) for temporarily collecting sheets disposed downstream of the discharge outlet, and a sheet from the processing tray means disposed downstream of the processing tray means. , A stack tray (29) for storing the sheet, a sheet disposed on the processing tray means, a stopper means (30) for regulating the position of the trailing edge, and a sheet disposed on the processing tray means from the sheet discharge port. And a sheet transfer means (35) for transferring the sheet toward the stopper means, and the sheet transfer means and the stopper means are disposed between the sheet transfer means and the stopper means. Aligning means (40) is provided.

  The aligning means is located between the sheet on the processing tray, the friction rotating body (40v) engaged and transferred to the stopper means, and the friction rotating body and the stopper means (30). The front end guide member (41) for guiding the front end of the sheet to the means, the friction rotating body, and a swing member (a swing lever 43 described later) for swingably supporting the front end guide member. Therefore, the swing rotation center of the swing member is disposed at a position where the contact force between the friction rotating body and the sheet is reduced by swinging by the lifting force of the sheet acting on the tip guide member.

  In the present invention, on a processing tray, a sheet transfer means and aligning means for transferring a sheet to a regulating stopper are arranged, and the aligning means is constituted by a friction rotating body provided on a swing member and a tip guide member, and a guide member Since the friction rotating body is swung in the direction of reducing the pressing force of the sheet by the pushing-up force of the sheet acting on the sheet, the following effects can be obtained.

  Since the sheet carried on the processing tray from the sheet discharge port is reliably sent to the regulation position by the friction rotating body and the leading edge guide member arranged on the upstream side of the regulation stopper, the leading edge of the sheet has not reached or curled at the leading edge of the sheet. There will be no misalignment of the seat over the restriction position.

  At the same time, if an excessive conveying force is applied to the sheet sent to the restriction stopper, the leading edge of the sheet is bent in a loop shape and the leading edge is bent. Swing. At this time, the rocking rotation center of the rocking member is arranged at a position to reduce the pressure contact force exerted on the sheet by the friction rotating body, so that the rotating body floats away from the sheet and reduces the conveying force exerted on the sheet. Will be. As a result, there are no problems such as bending of the leading edge of the sheet, uneven distortion, wrinkles and the like.

  Further, according to the present invention, the aligning means, for example, a swing lever, a transport rotating body and a guide member are attached to the lever, and the transport rotating body is lifted from the sheet by a pushing force applied to the guide at the center of the lever swing. What is necessary is just to set to a position and the structure can be provided very simply and cheaply.

1 is an explanatory diagram of an overall configuration of an image forming apparatus forming system according to the present invention. 2A and 2B are explanatory diagrams of a paper discharge unit (sheet post-processing apparatus) in the system of FIG. 1, in which FIG. FIGS. 3A and 3B are explanatory views of a paper discharge mechanism of the paper discharge unit of FIG. 2, in which FIG. FIG. 3 is an explanatory diagram of a paper surface detection structure of a stack tray in the paper discharge unit of FIG. 2. FIGS. 3A and 3B are explanatory diagrams of a side alignment mechanism in the paper discharge unit of FIG. 2, in which FIG. 3A is an explanatory diagram of a bottom structure of a processing tray, and FIG. FIG. 3 is an explanatory diagram of a lifting mechanism of a sheet transfer unit in the paper discharge unit of FIG. 2. FIGS. 3A and 3B are explanatory diagrams of aligning means in the paper discharge unit of FIG. 2, in which FIG. FIG. 8 is an explanatory diagram of an embodiment different from FIG. 7, showing aligning means in the paper discharge unit of FIG. 2. FIG. 2 is a block diagram showing a control configuration in the image forming system of FIG. 1. The flowchart which shows the operation state in the control structure of FIG. FIG. 6 is an explanatory diagram illustrating a sheet discharge state in a conventional sheet discharge device.

[Image forming system]
The image forming system shown in FIG. 1 includes an image forming apparatus A and a sheet post-processing apparatus B. The image forming apparatus A forms an image based on image data designated on the sheet, and places a sheet on the paper discharge port. It is configured to be carried out. The sheet post-processing apparatus B receives the image-formed sheet from the paper discharge port, aligns the sheet at a predetermined post-processing position, performs post-processing, and then places the processed sheet (bundle) on the stack tray. It is configured to accommodate. Each configuration will be described in detail.

[Configuration of Image Forming Apparatus]
The image forming apparatus A includes a paper feeding unit 2, an image forming unit 3, and an image data storage unit in a casing 1. The sheet feeding unit 2 is composed of, for example, a plurality of sheet feeding cassettes 11a, 11b, and 11c. Each cassette 11a to 11c stores a standard size sheet selected in advance. The paper feed unit 2 is provided with a manual feed tray (not shown) so that a user can insert a sheet according to the purpose of use. The sheet set in the sheet feeding unit 2 having such a configuration is a control panel 63 whose sheet conditions such as size, paper quality (coating paper or plain paper), paper thickness (thick paper or thin paper) and the like are described later. It is configured to input information from.

  The image forming unit 3 is configured to form an image on a sheet sent from the paper feeding unit 2, and the illustrated one shows an electrostatic image forming mechanism. The image forming unit 3 includes a photosensitive drum 13, a print head (laser light, LED light, etc.) 14 for forming a latent image on the drum surface, and an image forming unit Y (yellow). ), M (magenta), C (cyan), and K (black), four image forming units 3Y, 3M, 3C, and 3K are provided. The image ink (toner) formed on the photosensitive drums of the units 3Y to 3K is transferred to the transfer belt 16 by the transfer charger 17.

  Therefore, an electrostatic latent image is formed on the photosensitive drum 13 by the print bed 14, toner is adhered by the developing device 15, and this image is transferred onto the transfer belt 16 by the transfer charger 17. In the case of a color image, the final image is formed on the transfer belt 16 by superimposing YMCK color data on this image transfer. Then, this image is transferred onto the sheet sent from the paper feed unit 2 to the paper feed path P1. A charger 18 for transferring an image onto a sheet is shown in FIG.

  The sheet on which the image has been transferred in this manner is carried out to the paper discharge path P2 through the fixing device 19. In addition, the image forming unit 3 is not limited to the illustrated electrostatic image forming mechanism, and various image forming mechanisms such as an ink jet image forming mechanism and an offset image forming mechanism can be employed.

  Although not shown, the image data storage unit is configured by a storage memory for image data formed on the photosensitive drum 13 by the print head 14 of the image forming unit 3 so that data is transferred from the image reading unit 5 to the storage unit. It has become. Data is transferred to the image data storage unit also from, for example, a networked computer.

  In the image forming apparatus A configured as described above, an image reading unit 5 for reading a document image is mounted on the upper portion thereof, and a document feeding unit 6 is further mounted on the upper portion thereof. Although not shown, the image reading unit 5 includes a platen on which an original sheet is set, a reading carriage that scans the original image along the platen, and a photoelectric conversion unit that forms an image of reflected light from the original image and performs photoelectric conversion. 7 is provided. The document feeding unit 6 includes a feeder mechanism (not shown) that separates the document sheets set on the sheet feeding tray 9 one by one and automatically feeds them to the platen of the image reading unit 5.

[Sheet post-processing equipment]
The sheet post-processing apparatus B is built in the above-described image forming apparatus A as follows. The above-described image forming apparatus A carries out the sheet on which the image is formed on the sheet to the paper discharge path P2. The paper discharge path P2 is configured such that a paper discharge area 21 is disposed in the upper part of the casing 1, and a sheet on which an image is formed by the image forming unit 3 is carried out to the paper discharge area. The illustrated paper discharge area 21 is disposed between the upper portion of the image forming apparatus A and the image reading unit 5 disposed thereon (see FIG. 1).

  A sheet discharge unit is incorporated in the sheet discharge area 21, and the sheet post-processing apparatus B is configured to be incorporated in the casing 1 as one of the units. In the paper discharge path P2, a conveyance roller 22 is provided so as to carry out the sheet to the paper discharge area 21, and the sheet is fed out to a connection port 23 connected to the paper discharge unit.

  Next, a sheet post-processing apparatus (hereinafter referred to as “paper discharge unit”) B will be described with reference to FIG. The paper discharge unit B includes a paper discharge path (paper discharge path of the paper discharge unit; the same applies hereinafter) P3 connected to the connection port 23 of the paper discharge path P2, and a paper discharge port 24 provided at the exit end of this path. . A paper discharge roller 25 is provided at the paper discharge port 24 as a pair of rollers (25a, 25b), and a drive motor (not shown) is connected to the illustrated roller 25b.

  Further, an ejection path P4 is branched from the paper ejection path P3 of the paper ejection unit via a path switching flapper 26, and an overflow stacker (not shown) is disposed downstream of the ejection path P4. Yes. An overflow sheet, an interrupt job sheet, and the like are carried out to the overflow stacker. In the paper discharge path P3, a carry-in sensor S1 and a paper discharge sensor S2 are respectively arranged at the illustrated positions. The carry-in sensor S1 detects the leading edge of the sheet and controls the subsequent path switching flapper 26, the paper discharge roller 25, and the like. . The paper discharge sensor S2 detects the front and rear edges of the sheet and controls the subsequent sheet transfer means 31, aligning means 40, and the like.

  On the other hand, a step Hd (see FIG. 3A) is formed on the downstream side of the paper discharge port 24, and the processing tray 28 is disposed on the downstream side thereof. The processing tray 28 and the stack tray 29 are sized so that the stack tray 29 supports the leading edge of the sheet from the sheet discharge outlet 24 and the processing tray 28 bridges the trailing edge. That is, the processing tray 28 is configured to have a dimension shorter than the length of the smallest size sheet in the sheet discharge direction, and supports the rear end portion of the sheet whose front end portion is supported by the stack tray 29. Hereinafter, the processing tray 28 and the stack tray 29 will be described in this order.

[Processing tray configuration]
As shown in detail in FIG. 3 (a), the processing tray 28 is constituted by a tray member having a paper loading surface 28a, and a trailing edge regulating stopper (sheet edge regulating means; The same applies hereinafter) 30 is arranged. The paper loading surface 28a may have a shape that supports the sheet in a horizontal posture, or a shape that supports the sheet in an inclined posture so that the rear end side of the sheet (the rear end side in the paper discharge direction; the same applies hereinafter) is lowered. Also good.

  The rear end restricting stopper 30 is disposed at a distance Ld from the sheet discharge port 24, and a sheet end restricting surface 30a for restricting the rear end edge of the sheet to be abutted and a sheet pushing up restricting surface for restricting overcoming by curling of the sheet front end. It is comprised with the stopper member which has 30b. 30c shown in the figure is a front end pressing piece for restricting the front end of the sheet, and is made of an elastically deformable plate material. The base end is fixed to the stopper member 30 so as to correct the curled sheet front end (FIG. 3). (See (b)).

  The processing tray 28 is provided with a sheet transfer unit 31 that transfers a sheet from the sheet discharge outlet 24 toward the trailing edge regulating stopper 30 and a side alignment unit 32 that aligns the side edges of the sheets. The sheet transfer means 31 is configured to be movable up and down with respect to the paper placement surface 28a. The structure is shown in FIG. 2B. The sheet transfer means 31 is composed of a vertically swinging bracket (elevating support means; hereinafter the same) 34, a forward / reverse roller 35 supported by this, and an elevating motor MS. It is configured.

  The bracket 34 has a base end supported by an apparatus frame (not shown) supported by a swinging rotation shaft 33 and a forward / reverse rotation roller 35 supported by a bearing at the distal end. The forward / reverse roller 35 is connected to a forward / reverse motor MR to transfer the sheet in the left-right direction in FIG. Accordingly, when the forward / reverse roller 35 is rotated counterclockwise in FIG. 2B, the sheet is transferred to the trailing edge regulating stopper 30 side, and when rotated in the clockwise direction, the sheet is transferred to the stack tray 29 side.

[Elevating mechanism of forward / reverse roller]
The elevating mechanism of the forward / reverse roller 35 will be described with reference to FIGS. As shown in FIG. 2B, the swing rotation shaft 33 is supported by a device frame (not shown), and the rotation of the forward / reverse rotation motor MR is transmitted to the swing rotation shaft 33 as a gear (see FIG. 6). ). At the same time, a follower-side collar 34j integrally formed on the base end portion of the bracket 34 is loosely supported on the swing rotation shaft 33. Therefore, the bracket 34 swings about the rotation shaft regardless of whether the swing rotation shaft 33 is forward or backward.

  On the other hand, a drive side collar 34d is loosely supported by the swinging rotary shaft 33 adjacent to the driven side collar 34j, and a drive shaft MSd of the elevating motor MS is geared to the drive side collar 34d with a pinion 34p. ing. Therefore, the drive side collar 34d is rotated forward and backward by the drive shaft MSd of the elevating motor MS regardless of the rotation of the swing rotation shaft 33. A clutch spring CS is wound around the driving side collar 34d and the driven side collar 34j. The clutch spring CS is configured to be tightened by rotation of the driving side collar 34d in the direction indicated by an arrow a in FIG. 6 and relaxed by rotation in the opposite direction.

  As a result, when the drive side collar 34d is rotated in the direction indicated by the arrow a by the elevating motor MS, the clutch spring CS is contracted and the driven side collar 34j is rotated in the same direction. At this time, the bracket 34 integrated with the driven side collar 34j moves upward from the operating position Fp to the retracted position Wp. When the bracket 34 rises to the preset retracted position Wp, it hits an upper limit stopper 34u (shown in FIG. 2), and thereafter, the rotation of the sliding drive side collar 34d between the clutch spring CS and the driven side collar 34j is driven side. The frictional force is set so as not to be transmitted to the collar 34j.

  The frictional force is set such that when the clutch spring CS is contracted, the bracket 34 is held at the retracted position Wp by the frictional force between the spring and the driven collar 34j, and the bracket 34 is not lowered by its own weight. It is configured as follows. 34S shown in the figure is a position sensor that detects whether or not the bracket 34 is located at the retracted position Wp, and is configured integrally with the upper limit stopper 34u, both of which are attached to the apparatus frame.

  Next, when the drive side collar 34d is rotated in the direction opposite to the direction indicated by the arrow a by the elevating motor MS, the clutch spring CS is held in a contracted state, so that the bracket 34 descends from the retracted position Wp following the rotation. . The speed at this time is controlled by the rotational speed of the drive shaft MSd of the elevating motor MS.

  When the forward / reverse roller 35 supported at the tip of the bracket 34 comes into contact with the uppermost sheet on the processing tray 28, the clutch spring CS is rotated by the rotation of the driving side collar 34d (the loose side in the direction opposite to the arrow a direction). The bracket 34 comes to rest at the operating position Fp of the forward / reverse rotation roller 35 by loosening and sliding rotation between the spring and the driving side collar 34d. While the forward / reverse roller 35 is thus moved from the retracted position Wp to the operating position Fp, the control CPU 65 described later activates the forward / reverse motor MR to rotate the forward / reverse roller 35 counterclockwise in FIG. Then, the sheet is transferred to the rear end regulating stopper 30 side.

  Accordingly, the bracket 34 swings clockwise and counterclockwise about the swinging rotation shaft 33 by forward and reverse rotation of the lifting motor MS. That is, when the pinion 34p is rotated in the clockwise direction in the figure, the forward / reverse roller 35 is moved to the retracted position Wp separated from the paper loading surface 28a in the same figure, and when the pinion 34p is rotated in the counterclockwise direction, the forward / reverse roller 35 is moved to the solid line in the figure. The operation position Fp is in contact with the paper sheet surface 28a in the state. A forward / reverse rotation force is transmitted to the forward / reverse roller 35 from a forward / reverse motor MR (see FIG. 6) connected to the swing rotation shaft 33.

  A follower roller 36 is provided on the paper loading surface 28 a of the processing tray 28 so as to face the forward / reverse roller 35. The forward / reverse rotation roller 35 rotates counterclockwise in FIG. 2A when the sheet is transferred from the sheet discharge outlet 24 toward the trailing edge regulating stopper 30 by the forward / reverse rotation motor MR, and is post-processed from the trailing edge regulating stopper 30. When the sheet (bundle) is transferred to the stack tray 29 on the downstream side, the sheet rotates in the clockwise direction in FIG.

"Aligning means"
An aligning means 40 is disposed between the sheet transfer means 31 and the trailing edge regulating stopper 30. The aligning means 40 shown in the drawing, in cooperation with the sheet transfer means 31, transfers the sheet rear end carried out from the sheet discharge outlet 24 toward the rear end restriction stopper 30. Therefore, as shown in FIG. 7B, the aligning means 40 includes a ring-shaped belt (hereinafter referred to as “aligning belt”) 40v and a swing that moves the belt up and down in accordance with the sheet stacking amount of the processing tray 28. And lever 43.

  One end (upper end in FIG. 7) of the swing lever 43 is pivotally supported by the rotary shaft 42 of the paper discharge roller (drive side roller) 25b described above, and one end of the aligning belt 40v is wound around the paper discharge roller 25b. It is disguised. The leading end of the belt hangs down to a position where it engages with the sheet on the processing tray 28. Accordingly, the aligning belt 40v also rotates counterclockwise in FIG. 7A by the driving rotation of the paper discharge roller 25b, and the swing lever 43 swings by its own weight around the rotation shaft 42.

  A tip guide member 41 is fixed to the swing lever 43 together with the aligning belt 40v. The leading edge guide 41 is formed of a film member (mylar) that guides the trailing edge of the sheet fed by the aligning belt 40v toward the trailing edge regulating stopper 30. The rotation center 42o of the rotation shaft 42, the sheet engagement point 40p of the aligning belt 40v, and the sheet engagement point 41p of the leading end guide 41 are spaced apart in the order of the rotation center 42o, the engagement point 40p, and the engagement point 41p in the sheet transfer direction. They are spaced apart (see FIG. 7A).

  The present invention is characterized in that the aligning means 40 is configured as described above. The configuration will be described in detail. As an aligning means 40, a friction rotating body 40v that engages with the uppermost sheet carried on the processing tray 28 is provided. The friction rotating body 40v is not limited to the belt as shown in the figure, and various structures such as a sponge roller, a rubber roller, a rubber ring, or a paddle member can be adopted.

  The friction rotator 40v is disposed between the paper discharge port 24 and the processing tray 28, and the sheet ends indicated by “a” in FIG. 7A are discharged in the order of “b” and “c” by the rotation. Guiding is performed along the paper loading surface 28a of the tray 28. Simultaneously with the sheet rear end guide function, the friction rotating body 40v transfers the sheet between the sheet loading surface 28a and the rear end regulating stopper 30 side. This conveying force application function cooperates with the above-described sheet conveying means 31 to apply a conveying force so that the sheet smoothly reaches the trailing edge regulating stopper 30 without being skewed.

  For this reason, the friction rotating body 40v presses the carry-in sheet with its own weight, for example, and applies a conveying force by the rotation. At the same time, the sheet engagement point 40p that imparts the conveyance force needs to rise according to the sheet stacking amount on the processing tray 28. For this reason, the illustrated friction rotating body 40v is supported by a swing lever 43 (not limited to the lever, but any swing member). The swing lever 43 is pivotally supported by the apparatus frame and other members so as to be swingable. The illustrated one is supported by a rotating shaft 42 of a paper discharge roller 25b, and is configured to be swingable about this shaft.

  Therefore, in the present invention, a leading edge guide member 41 for guiding the leading edge of the sheet to the stopper means is provided between the friction rotating body 40v and the trailing edge regulating stopper 30. The tip guide member may be composed of a film-like elastic piece such as Mylar as shown, or may be composed of a paper pressure plate such as synthetic resin or metal. The tip guide member 41 is configured to be swingable about a support shaft. This is for raising according to the sheet stacking amount of the paper loading surface 28a. Therefore, in the embodiment shown in FIG. 7, the base end portion of the tip guide member 41 is fixedly supported by the swing lever 43 together with the friction rotating body 40v.

  Therefore, the friction rotating body 40v and the tip guide member 41 are supported on the swing lever 43 that can swing around the rotation shaft 42. The rotation center 42o of the rotation shaft 42, the sheet engagement point 40p of the friction rotating body 40v, and the sheet engagement point 41p of the leading end guide member 41 are arranged in this order from the upstream side to the downstream side in the sheet transfer direction. That is, as shown in FIG. 7A, a distance (Lz1) is arranged between the rotation center 42o and the engagement point 40p, and a distance (Lz2) is arranged between the engagement point 40p and the engagement point 41p. It is.

  Therefore, when an excessive conveying force (the factor will be described later) is applied to the sheet from the sheet conveying means 31 described above, after the sheet trailing edge hits the trailing edge regulating stopper 30 as shown in FIG. A force that curves in a loop acts. Regardless of the bending deformation force acting on the sheet, if the sheet continues to be conveyed to the stopper side by the sheet transfer means 31 and the friction rotating body 40v, the rear end of the sheet is locally deformed, leading to leading edge bending.

  However, as described above, when the lifting force “f” is applied to the front end guide member 41 from the rear end of the sheet, a rotation moment about the rotation shaft 42 is applied to the swing lever 43, and this moment causes the swing lever. 43 rotates counterclockwise by the angle θ. This rotation creates a gap Ga between the friction rotating body 40v and the upper surface of the sheet. With the gap Ga formed in this way, the sheet extends in the direction of the arrow g without bending in a loop shape. As a result, it is possible to prevent wrinkles at the rear end of the sheet and breakage of the front end.

[Different embodiments of aligning means]
Next, the embodiment shown in FIG. 8 shows a case where the friction rotating body 40v is supported by the first swing lever 43A and the tip guide member 41 is supported by the second swing lever 43B. The same components as those in FIG. The friction rotating body 40v is composed of a belt, a roller and the like as described above, and is rotatably supported by the first swing lever 43A. The rotation in the direction of transferring the sheet to the trailing edge regulating stopper 30 is transmitted to the friction rotating body 40v from a drive motor (not shown). This drive motor may be transmitted from the rotation shaft of the paper discharge roller 25b or may be provided with an independent drive motor.

  The first swing lever 43A is supported by the apparatus frame so as to be swingable about the rotation shaft 42A. Accordingly, the friction rotating body 40v moves up and down at the sheet engagement point 40p that engages with the uppermost sheet (loading sheet) on the processing tray 28 around the rotation shaft 42A.

  On the other hand, the front end guide member 41 is formed of a plate-like sheet pressing piece such as metal or resin, and a base end portion is fixed to the second swing lever 43B, and the front end portion thereof is the friction rotating body 40v and the rear end regulating stopper. 30. The second swing lever 43B is supported by the apparatus frame so as to be swingable about the rotation shaft 42B, and the sheet engagement point 41p of the leading end guide member 41 moves up and down according to the stacking amount of sheets. Yes.

  Therefore, the second swing lever 43B and the first swing lever 43A are connected to each other so as to transmit the swing of the second swing lever 43B to the swing motion of the first swing lever 43A. For this connection, for example, both may be connected by a connecting pin, but in the illustrated example, a bent piece 43L is formed on the first swing lever 43A, and the connecting portion between the bent piece 43L and the second swing lever 43B. 43N is connected so as to engage with each other. Therefore, when the second swing lever 43B swings about the rotation shaft 42B in the counterclockwise direction in the drawing, the connecting portion 43N pushes up the bent piece 43L of the first swing lever 43A. As a result, the first swing lever 43A also swings in the same direction around the rotation shaft 42A.

  Also in this embodiment, the rotation center 42Ao of the first swing lever 43A, the sheet engagement point 40p of the friction rotating body 40v, and the sheet engagement point 41p of the tip guide member 41 in the sheet transfer direction are the same as in the previous example. They are arranged at a distance in this order from the upstream side in the sheet transfer direction. The rotation axis center 42Bo of the second swing lever 43B is disposed at a position spaced from the sheet engagement point 41p of the front end guide member 41 on the upstream side or the downstream side in the sheet conveyance direction. This is because the rotational force of the rotation center 42Bo is generated in the second swing lever 43B by the lifting force of the sheet acting on the sheet engagement point 41p.

  When the aligning means 40 configured in this manner has an excessive conveying force applied to the sheet from the sheet conveying means 31 described above, the trailing edge of the sheet is regulated as shown in FIG. 8B. After hitting the stopper 30, a force that curves in a loop acts. When the lifting force “f” acts on the leading end guide member 41 due to the deformation of the sheet, a rotational moment about the rotation shaft 42B acts on the second swing lever 43B.

  By this moment, the second swing lever 43B rotates counterclockwise by the angle θb. The rotation of the second swing lever 43B is transmitted from the connecting portion 43N to the first swing lever 43A, and the first swing lever 43A rotates counterclockwise by an angle θa about the rotation shaft 42A. . This rotation creates a gap Ga between the friction rotating body 40v and the upper surface of the sheet. With the gap Ga formed in this way, the sheet extends in the direction of the arrow g without bending in a loop shape. As a result, it is possible to prevent wrinkles and tip breaks at the rear end of the sheet in the same manner as described above.

  Next, the cause of the excessive conveyance of the sheet by the sheet conveying means 31 will be described. The aforementioned sheet transfer means 31 is disposed on the processing tray 28 and is configured to move up and down between the retracted position Wp and the operating position Fp. In the paper discharge path P3, a paper discharge sensor S2 is disposed upstream of the paper discharge port 24.

  Therefore, when the sheet is carried out from the paper discharge roller 25 of the paper discharge path P3 onto the processing tray 28, as described with reference to FIG. The sheet transfer means 31 is located at the retracted position Wp. For this reason, after the trailing edge of the sheet passes through the paper discharge port 24, the sheet is dropped onto the processing tray 28 by its inertia. For this reason, a thick paper sheet with a large basis weight (mass) or a sheet for single-sided printing is far from the paper discharge port 24 compared to a thin paper sheet with a small basis weight (mass) or a double-sided printing sheet with a small surface friction coefficient. Land at a position, the latter landing at a close position.

  In this way, the distance between the sheet rear end and the rear end regulating stopper 30 is different each time. Therefore, in order to prevent the rear end of the sheet from reaching, it is necessary to set the sheet transfer amount by the sheet transfer unit 31 and the aligning unit 40 to be overrun. Thus, when the sheet is excessively conveyed, it is necessary to set a conveyance condition in which slip occurs between the sheet and the friction rotator 40v. This conveyance condition causes a problem that the sheet is skewed. Therefore, when the sheet is abutted against and conveyed by the trailing edge regulating stopper 30 by the friction rotating body 40v described above, there arises a problem that the sheet edge is curved in a loop shape.

"Side alignment means"
The processing tray 28 is provided with side alignment means 32 for regulating the position of the side edge of the sheet whose rear end is positioned on the rear end regulating stopper 30 described above. The side aligning means 32 includes a center reference for aligning with respect to the center (center) of the sheet carried into the processing tray 28 from the sheet discharge outlet 24, and a side reference for aligning with respect to the left and right side edges of the sheet. The side edge of the sheet is configured to be aligned to one of the reference positions.

  As shown in FIG. 5, the side aligning means 32 includes a left aligning plate 32L that engages with the left edge of the sheet carried into the processing tray 28, a right aligning plate 32R that engages with the right edge of the sheet, and aligning these. Alignment motors Mz1 and Mz2 move the plate in the direction perpendicular to the paper discharge. The left and right alignment plates 32L and 32R are fitted and supported in slit grooves 28z formed on the paper loading surface 28a of the processing tray, respectively, and can be moved in the sheet width direction. A pair of pulleys 32p is disposed at the bottom of the tray along the slit groove 28z, and a belt 32v is stretched over the pulleys 32p. The left and right alignment plates 32L and 32R are fixed to the belt 32v, and the alignment motors Mz1 and Mz2 are coupled to one of the pulleys 32p.

  When the alignment motors Mz1 and Mz2 are rotated in the opposite direction by the same amount, the left and right alignment plates 32L and 32R approach and separate from the sheet center. The left and right alignment plates 32L and 32R are provided with position sensors at preset home positions, and the alignment plates 32L and 32R are positioned at the home positions when the apparatus is activated.

  Therefore, a control means (control CPU) 65, which will be described later, receives sheet size information from the image forming apparatus A, and based on this information, the control means places the left and right alignment plates 32L and 32R in a predetermined standby position (FIG. 5B). Move to Wp) and wait. The standby position Wp is set to a position (a position for forming the alignment operation width) that is a predetermined amount away from the width size of the sheet carried into the processing tray 28.

  Therefore, the control means 65 reverses the left and right alignment motors Mz1 and Mz2 after the expected time that the trailing edge of the sheet conveyed from the paper discharge port 24 reaches the trailing edge regulating stopper 30 (after a predetermined time has elapsed from the paper discharge sensor S2). The left and right alignment plates 32L and 32R are moved to the alignment position (Ap in FIG. 5B) by rotating synchronously by a predetermined amount in the direction. As a result, the sheets carried onto the processing tray are aligned and aligned.

[Post-processing means]
The post-processing means 37 arranged on the processing tray 28 will be described. As shown in FIG. 3, the post-processing means 37 is built in the casing 8 of the paper discharge unit B so as to perform post-processing on the sheet (bundle) regulated against the rear end regulating stopper 30. The illustrated post-processing means 37 is composed of staple means. Since the stapling means (apparatus) is well known, its description is omitted. However, the stapling needle (blank) connected in a strip shape accommodated in the cartridge is folded into a U-shape and inserted into the sheet bundle with a driver member. Enter. The needle tip is composed of a unit that bends with an anvil member arranged to face the driver member.

  A drive cam and a staple motor are mounted on the unit frame 10, and a driver member is lowered by an instruction signal from a post-processing control unit (control CPU) 65 described later to execute a staple operation. The unit frame 10 is slidably fitted and supported on the guide rails 38a and 38b, and is configured to be movable in the width direction of the sheets (bundles) on the processing tray 28. Further, a screw shaft 39 is fixedly disposed on the unit frame 9, and the stapling means 37 is moved in the sheet width direction by a drive motor (not shown).

[Stack Tray Configuration]
The configuration of the stack tray 29 will be described. The stack tray 29 is disposed on the downstream side of the processing tray 28 and is configured by a tray member that moves up and down according to the amount of sheets stacked. As shown in FIG. 2 (a), the tray member 29 having a placement surface 29a on which a sheet is placed is supported by a tray frame 44 fixed to the apparatus frame so as to be movable up and down. That is, a pair of link link levers 46 a and 46 b connected to each other by the support shaft 45 are provided, and each lever base end is pivotally supported by the tray frame 44 so as to be swingable.

  A tray member (stacked tray: the same applies hereinafter) 29 is supported by slit-pin connections at the leading ends of the link levers 46a and 46b. Fitting slits 29b and 29c are provided on the tray member side, and the leading ends of the link levers 46a and 46b are connected to the slits by pins 46c and 46d.

  A lift motor ML is gear-connected to the support shaft of one link lever 46a via a worm gear. Accordingly, the link lever 46a swings in the left-right direction in FIG. 2 by forward and reverse rotation of the lift motor ML, and the link lever 46b swings in the opposite direction by the same amount, and the tray member 29 moves up and down in a parallel posture. It becomes. The tray member 29 is provided with a paper surface detecting means 47 for detecting the paper surface position.

[Structure of paper surface detection means]
The structure of the paper surface detection means 47 is shown in FIG. 4, and is arranged at the sheet carry-in port (the right end of the same figure) of the tray member 29, and detects the position of the uppermost surface of the sheets deposited on the placement surface 29a. For this reason, the paper surface detection lever 47a that is in contact with the uppermost sheet, the operation solenoid 48 that retracts the paper surface detection lever 47a from the placement surface when the sheet is loaded, and contacts the sheet surface after the sheet is loaded, and the detection position of the paper surface detection lever 47a. It consists of sensors 49a and 49b to detect.

  The paper surface detection lever 47a is supported by the apparatus frame so as to be swingable by a support shaft 47b, and is always urged by a spring 50 toward the retracted position. The paper surface detection lever 47a is integrally provided with a flag 47c, and the rotational displacement of the flag 47c is detected ON / OFF by the first sensor 49a and the second sensor 49b.

  The paper surface detection lever 47a is shifted from the retracted position to the detection position (solid line state in FIG. 4) against the spring 50 by the operating solenoid 48, and at this time, the position of the uppermost paper surface on the tray is detected. . The first and second sensors 49a and 49b and the flag 47c are set to the home position when the first sensor 49a shown in FIG. 4 is “OFF” and the second sensor 49b is “ON”. is there.

  Accordingly, when both the first and second sensors 49a and 49b are “ON”, the detection paper surface is too high, and the tray member 29 is lowered by a predetermined amount. When both the first and second sensors 49a and 49b are “OFF”, the detection paper surface is too low and the tray member 29 is raised by a predetermined amount. Reference numeral 51 in the figure denotes a lower limit sensor that detects the lower limit position of the tray member 29.

  The loading surface 29a of the stack tray 29 is moved up and down by the detection signal of the paper surface detecting means 47. The vertical movement of the tray controls the lift motor ML described above. For example, when the lift motor ML is configured by a DC motor, the rotation amount is controlled by the power supply time to the motor, or an encoder is provided on the motor rotation shaft and the rotation amount is controlled by an encoder pulse. When the lift motor is a pulse motor, the amount of rotation is controlled by a power pulse.

[Description of control configuration]
The control configuration of the above-described image forming system will be described with reference to the block diagram of FIG. The image forming system shown in FIG. 1 includes a control unit (hereinafter referred to as “main body control unit”) 60 of the image forming apparatus A and a control unit (hereinafter referred to as “post-processing control unit”) 65 of the post-processing apparatus B. The main body control unit 60 includes a print control unit 61, a paper feed control unit 62, and an input unit (control panel) 63.

  Then, an “image forming mode” and a “post-processing mode” are set from the input unit (control panel) 63. The image forming mode sets mode settings such as color / monochrome printing, duplex / single-sided printing, and image forming conditions such as sheet size, sheet paper quality, number of printouts, and enlarged / reduced printing. The “post-processing mode” is set to, for example, “print-out mode”, “steple finishing mode”, “binding binding finishing mode”, or the like.

  The main body control unit 60 also sends a post-processing finishing mode and the number of sheets, information on the number of copies and binding mode (single-position binding or two or more bindings) information, and the sheet thickness of the sheet on which an image is formed. Data transfer such as information. At the same time, the main body control unit 60 transfers a job end signal to the post-processing control unit 65 every time image formation is completed.

  The above-described post-processing mode will be described. In the “print-out mode”, the sheet from the paper discharge port 24 is stored in the stack tray 29 without performing post-processing. In this case, the sheets are conveyed directly from the sheet discharge outlet 24 to the stack tray 29 without being aligned and stacked on the processing tray 28. In the “steple finishing mode”, the sheets from the sheet discharge outlet 24 are stacked on the processing tray 28 to be aligned, and the sheet bundle is bound by the stapler 37 and then stored in the stack tray 29. In this case, the sheet to be imaged is in principle designated by the operator to a sheet of the same paper thickness and the same size.

  In the “binding binding finishing mode”, sheets formed by the image forming apparatus A are arranged and collected on the processing tray, and finally the cover sheet is formed by the image forming apparatus A and superimposed on the sheets on the processing tray. After stapling, the staple is stored in the stack tray 29. In this case, the cover sheet is designated by the operator as a cardboard sheet prepared in the paper feed cassette.

[Post-processing control unit]
The post-processing control unit 65 is configured by a control CPU 65 (control means; hereinafter the same) that operates the post-processing apparatus B in accordance with a designated post-processing mode. The control unit includes a ROM 66 that stores an operation program and a RAM 66 that stores control data.

  The operation program determines whether or not the bracket 34 is positioned at the retracted position Wp based on a signal from the position sensor 34S at the time of initialization (initialization) when the apparatus is activated. When the sensor signal is OFF, the lifting / lowering motor MS is activated in the upward direction and the bracket 34 is positioned at the retracted position. The operation program is configured to rotationally drive the paper discharge roller 25 and to rotate the friction rotating body 40v of the aligning means 40 in response to a signal detected by the carry-in sensor S1.

  The operation program starts the timer T when the sheet discharge sensor S2 detects the trailing edge of the sheet, and starts the elevating motor MS in the downward ascending direction by the time-up signal of the timer T to swing the bracket 34. Thus, the forward / reverse roller 35 is lowered from the retracted position Wp to the operating position Fp. The forward / reverse rotation motor MR is configured to rotate counterclockwise in FIG. 2 before the forward / reverse rotation roller 35 reaches the operating position Fp.

[Discharge Operation Flow]
The operation of the control means 65 configured as described above will be described with reference to the flowchart shown in FIG. When the apparatus power is turned on (St01), the paper discharge unit B performs an initial operation together with the image forming apparatus A (St02). In this initial operation, the control means 65 positions the forward / reverse rotation roller 35 at the standby position Wp.

  Next, the control unit 65 detects that the leading edge of the sheet on which the image is formed by the image forming apparatus A reaches the carry-in sensor S1 (St03). Based on the sheet leading edge detection signal from the sensor S1, the control means 65 rotates the paper discharge roller 25 in the paper discharge direction (St04). At the same time, when the post-processing mode is set to the aforementioned printout mode, staple finishing mode or bookbinding binding finishing mode, the path switching flapper 26 is shifted to the state shown in FIG. As a result, the sheet is guided to the path paper discharge port 24. When the interrupt mode is set, the route switching flapper 26 guides the sheet to the ejection route P4. As the paper discharge roller 25 rotates, the friction rotator 40v also starts to rotate in the paper discharge direction (St05).

  When the sheet reaches the paper discharge roller 25, the sheet is gradually carried out from the front end onto the processing tray 28 by the rotation. At this time, the control means 65 starts the timer T with a detection signal detected by the paper discharge sensor S2 at the trailing edge of the sheet. The timer T counts the CPU internal clock or counts the clock provided by the external i. Before starting the timer, the control unit 65 calls the timer time from the RAM 66 and sets the timer time Tt according to the above-described image forming conditions transferred from the image forming apparatus A.

  Next, the control means 65 determines whether or not the sheet discharge sensor S2 is OFF and the trailing edge of the sheet has passed the sensor (St06). Then, the timer is started by the sensor signal that the rear end of the sheet has passed the sensor position and time is measured (St07). Then, when the set timer time Tt has passed (St08), the control means 65 rotationally drives the aforementioned lifting motor MS in the downward direction. Then, the sheet discharge rotator 35 supported by the bracket 34 starts to descend from the retracted position Wp to the operating position Fp. Immediately after the timer time Tt has elapsed (or at the same time), the control means 65 drives the forward / reverse rotation motor MR to rotate (St10). This rotation direction is set in a direction opposite to the paper discharge direction for transferring the sheet to the trailing edge regulating stopper 30 side.

  The sheet that has passed through the sheet discharge outlet 24 by such control has its trailing edge landed on the processing tray. At this time, the sheet discharge rotator 35 is shifted from the retracted position Wp to the operating position Fp that engages with the sheet (St11). Then, the sheet is transferred toward the trailing edge regulating stopper 30 by the rotation of the sheet discharge rotating body 35 (St12). At this time, the aligning means 40 also sends the sheet in the same direction and assists its movement. Therefore, the rear end of the sheet is abutted and aligned with the rear end regulating stopper 30 as shown in FIG.

A Image forming apparatus B Sheet post-processing apparatus (paper discharge unit)
P3 Paper discharge path P4 Eject path MR Forward / reverse motor S1 Carry-in sensor S2 Paper discharge sensor 24 Paper discharge port 25 Paper discharge roller 25a Roller pair 25b Roller pair (drive side roller)
28 Processing tray 28a Paper loading surface 29 Stack tray (tray member)
29a Placement surface 30 Rear end regulating stopper (sheet end regulating means)
30a Sheet end regulating surface 30b Sheet raising regulating surface 30c Tip pressing piece 31 Sheet transfer means 32 Side alignment means 33 Oscillating rotation shaft 34 Bracket (lifting support means)
34u Upper limit stopper 34S Position sensor 35 Forward / reverse roller (paper discharge rotator)
36 driven roller 37 post-processing means 40 aligning means 40v aligning belt 41 tip guide member (film member)
42 Rotating shaft (42A, 42B)
42o Rotation center 40p Seat engagement point 41p Seat engagement point 43 Swing lever 43A First swing lever 43B Second swing lever 43L Bending piece 43N Connecting portion 65 Post-processing control portion 66 RAM
67 ROM

Claims (6)

The paper exit,
Processing tray means disposed downstream of the paper discharge port for temporarily collecting sheets;
A stack tray disposed downstream of the processing tray means and storing sheets from the processing tray means;
Stopper means arranged on the processing tray means for regulating the position of the trailing edge of the sheet;
A sheet transfer means disposed on the processing tray means for transferring a sheet from the discharge port toward the stopper means;
An aligning means that is disposed between the sheet transfer means and the stopper means, and abuts and transfers the sheet sent by the sheet transfer means to the stopper means;
With
The aligning means includes:
A friction rotating body that engages with the sheet on the processing tray and transfers the sheet to the stopper means;
A leading edge guide member that is positioned between the friction rotating body and the stopper means and guides the leading edge of the sheet to the stopper means;
A swinging member that swingably supports the friction rotating body and the tip guide member;
Consists of
The rocking rotation center of the rocking member is disposed at a position where the rocking member is rocked by the lifting force of the sheet acting on the tip guide member to reduce the pressure contact force between the friction rotating body and the sheet. A sheet post-processing apparatus. The swing member is
An oscillating shaft support rotatably supported by the device frame;
A rotating body bearing portion that supports the friction rotating body;
A guide fixing portion for fixing a proximal end portion of the tip guide member;
With
The swinging shaft support portion, the rotating body bearing portion, and the guide fixing portion are:
The sheet post-processing apparatus according to claim 1, wherein the sheet moving unit is arranged in this order in a moving direction of the sheet toward the stopper unit by the sheet transfer unit. The rocking member is supported by the apparatus frame so that the friction rotating body and the tip guide member engage with a sheet on the processing tray under its own weight with the rocking shaft support portion as a center. The sheet post-processing apparatus according to claim 1. The swing member is
A first swing lever for swingably supporting the friction rotating body;
A second swing lever for swingably supporting the tip guide member;
Consists of
The first and second swing levers are connected so that a height position of the friction rotating body is driven according to a height position of the tip guide member. Sheet post-processing equipment. The friction rotator is constituted by a belt member whose engagement height with a sheet changes according to a stacking amount of sheets on the processing tray means,
The sheet post-processing apparatus according to claim 1, wherein a driving force for transferring the sheet toward the stopper means is applied to the belt member. An image forming apparatus for sequentially forming images on sheets;
A sheet post-processing apparatus that performs post-processing on a sheet from the image forming apparatus;
Consisting of
6. The image forming system according to claim 1, wherein the sheet post-processing apparatus includes the configuration according to claim 1.

Images