JP4695861B2 - Sheet post-processing apparatus and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a sheet post-processing apparatus that performs a binding process and a punching process on a sheet conveyed from an image forming unit, and an image forming apparatus such as a printer, a copier, and a facsimile machine including the sheet post-processing apparatus.

  In general, a sheet post-processing apparatus performs post-processing such as binding (stapling) processing and punching processing on a sheet on which an image is formed by a printer, a copying machine, or the like.

  In the case of the staple processing, the sheets on which images are formed one after another by an image forming unit such as a printer or a copying machine are successively conveyed to a sheet post-processing apparatus, and are discharged and stacked on a post-processing tray. The stacked sheets are aligned at the ends to form a sheet bundle. Staple processing is performed on the sheet bundle. The sheet bundle after the stapling process is moved from the post-processing tray to another stacking tray.

  In such a sheet post-processing apparatus, the sheet to be stapled next cannot be discharged onto the post-processing tray while the stapling process is performed on the post-processing tray. For this reason, the image formation is interrupted until the stapling process of the previous sheet bundle is completed and the sheet bundle is moved to another stacking tray. As a result, productivity decreases.

  Patent Document 1 describes a sheet post-processing apparatus provided with a buffer unit in order to solve this problem. A buffer unit is provided on the upstream side of the post-processing tray so that sheets after image formation are temporarily stored (standby). That is, during the stapling process for the sheet bundle, an image is formed on the first sheet of the sheet bundle to be stapled next, and the first sheet is stored in the buffer unit. Further, an image is formed on the second sheet and stored in the buffer unit. Then, after the end of the stapling process for the previous sheet bundle, the leading ends of the first sheet and the second sheet are aligned and discharged and stacked on the post-processing tray. As a result, even during the stapling process, the image formation can be continued without interruption, thereby preventing a reduction in throughput, that is, a reduction in productivity.

  As described above, the sheet post-processing apparatus of Patent Document 1 superimposes the stored first sheet and the subsequent second sheet, and discharges and stacks them on the post-processing tray. The discharged sheet descends along the inclined surface of the post-processing tray due to its own weight, and comes into contact with a sheet abutting member (stopper member) near the stapler and stops. Further, a rotational alignment member (winding member) is provided above the post-processing tray, and this rotational alignment member is disposed on the upper surface of the upper sheet of the two sheets descending along the inclined surface of the post-processing tray. Touched. The upper sheet on the post-processing tray is surely brought into contact with the stopper member by the rubbing action of the rotational alignment member.

Japanese Patent Laid-Open No. 9-235069

  However, in the configuration described in Patent Document 1, when the lower sheet of the two sheets discharged and stacked so as to overlap the post-processing tray does not come into contact with the stopper member due to its own weight, the sheet Since the rotation alignment member for aligning the sheet is provided only above the post-processing tray, the lower sheet cannot be aligned, which may cause alignment failure.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a sheet post-processing apparatus that can prevent a decrease in productivity by performing post-processing and can reliably align sheets on a post-processing tray. .

According to the present invention, in a sheet post-processing apparatus that performs post-processing on a conveyed sheet, a buffer unit that temporarily stores the conveyed sheet, and two sheets stored in the buffer unit are stacked and discharged. Discharging means, a post-processing tray on which sheets discharged from the discharging means are stacked , an abutting member in which an end portion of the sheet on the post-processing tray is abutted and aligned, and the post-processing tray A lower rotating body that applies a conveying force in an alignment direction toward the abutting member by rubbing against the lower surface of the lower sheet of the two sheets that are stacked and stacked on the post-processing tray. and a rotary body on which imparts conveyance force alignment direction towards the abutment member rubs the upper surface of the upper sheet of the two sheets which are discharged, said abutment member, the rear Processing tray A rear end abutting member that abuts the rear end of the sheet discharged in the discharge direction, and a side end abutting member that abuts a side end in a direction orthogonal to the sheet discharge direction, and the lower rotation The body and the upper rotating body have a rotation shaft inclined with respect to the sheet discharge direction, and abut the sheet against the rear end abutting member and the side end abutting member by rotating in contact with the sheet. It is characterized by matching .
Further, the present invention provides a sheet post-processing apparatus that performs post-processing on a conveyed sheet, a buffer unit that temporarily stores the conveyed sheet, and two sheets stored in the buffer unit. A discharge means for discharging the sheet, a post-processing tray on which the sheet discharged from the discharge means is stacked, and a rear end abutting member against which a rear end of the sheet discharged in the discharge direction is abutted And a side end abutting member against which a side end in a direction orthogonal to the sheet discharge direction is abutted, and a rotation shaft extending in a direction orthogonal to the sheet discharge direction, and are stacked and discharged on the post-processing tray. A lower rotating body that rubs the lower surface of the lower sheet of the two sheets and applies a conveying force in an alignment direction toward the rear end abutting member, and a rotation that extends in a direction perpendicular to the sheet discharge direction An upper rotation that slides on the upper surface of the upper sheet of the two sheets discharged on the post-processing tray and applies a conveying force in the alignment direction toward the rear end abutting member. And a width adjusting member that pushes a side edge of the sheet toward the side edge abutting member.

  The present invention also provides an image forming apparatus including an image forming unit that forms an image on a sheet and a sheet post-processing device that performs post-processing on the sheet after image formation. This is a sheet post-processing apparatus.

  According to the present invention, even when the post-processing unit performs post-processing on the sheet discharged on the post-processing tray, the buffer unit can store the sheet, thereby preventing a decrease in productivity. Can do. Further, after being stored in the buffer means and aligned with the two sheets discharged so as to overlap the post-processing tray, the lower sheet abuts against the abutting member by the lower aligning member, and the upper sheet is aligned. Can be abutted against the abutting member by the upper alignment member for alignment. That is, since the lower alignment member and the upper alignment member are respectively provided below and above the post-processing tray, the two sheets on the post-processing tray can be aligned at the same time in a short time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, what attached | subjected the same code | symbol in each drawing has the same structure or effect | action, The duplication description about these was abbreviate | omitted suitably.

<Embodiment 1>
FIG. 1 shows a sheet post-processing apparatus 200 to which the present invention can be applied and an image forming apparatus 10 including the same. Note that the image forming apparatus 10 according to the present invention includes a sheet processing apparatus 200 as a part of its configuration. Therefore, in the following description, a part of the image forming apparatus 10 excluding the sheet post-processing apparatus 200 is referred to as the image forming apparatus main body 100 and is distinguished from the image forming apparatus 10.

  FIG. 1 is a schematic longitudinal sectional view as seen from the front side of the image forming apparatus 10 including the image forming apparatus main body 100 and the sheet post-processing apparatus 200 (the side on which the user is located when the image forming apparatus 10 is used). An image reading device 300 is disposed on the upper part of the image forming apparatus 10. Note that only the outer shape of the image reading apparatus 300 is illustrated.

  The image forming apparatus 10 shown in the figure has an in-machine discharge type configuration in which a sheet on which an image is formed and subjected to post-processing is discharged in a space between the image forming apparatus main body 100 and the image reading apparatus 300. Adopted. The image forming apparatus 10 applies an image process to a sheet by an image process described later based on image information sent from a connected computer (not shown) or a network such as a LAN, or image information read by the image reading apparatus 300. Thus, an image is formed, and further post-processing is performed as necessary, and then the sheet is discharged. Hereinafter, the image forming apparatus main body 100 will be described first, and then the sheet post-processing apparatus 200 will be described.

  First, the configuration and operation of the image forming apparatus main body 100 will be described with reference to FIG. In the present embodiment, an image forming apparatus main body 100 that forms a toner image on the sheet S by electrophotography will be described as an example.

  The image forming apparatus main body 100 includes a sheet feeding / conveying unit 101, an image forming unit 102, a fixing unit 103, and a paper discharge unit 104 in order from the upstream side to the downstream side in the conveyance direction of the sheet S.

  Among them, the feeding / conveying unit 101 includes an upper sheet feeding cassette 105, a lower sheet feeding cassette 106, an upper sheet feeding roller 106, sheet feeding rollers 107 and 108, a conveying guide 109, a registration roller 110, and the like.

  In the paper feed cassettes 105 and 106, a plurality of sheets S to be used for image formation are stored in a stacked state. In the present embodiment, the upper sheet cassette 105 and the lower sheet cassette 106 store sheets S of different sizes. The sheet S to be used for image formation is separated and fed one by one from the upper sheet cassette 105 or the lower sheet cassette 106 by the sheet feeding roller 107 or the sheet feeding roller 108, and conveyed along the conveyance guide 109. It is temporarily stopped by the registration roller 110. Once stopped, the sheet S is supplied to the image forming unit 102 by the registration roller 110 so as to be synchronized with a toner image formed by the image forming unit 102 described below.

  The image forming unit 102 includes a photosensitive drum 111 that rotates in the direction of the arrow (clockwise in FIG. 1), a charging roller 112, an exposure device 113, and a developing device 114 that are arranged almost sequentially along the rotation direction of the photosensitive drum 111. And a transfer roller 115, and a toner image is formed on the sheet S by an image forming process using these process devices.

  The surface of the photosensitive drum 111 is uniformly charged to a predetermined polarity and potential by the charging roller 112. The surface of the photosensitive drum 111 after charging is exposed to a laser beam L corresponding to image information by an exposure device 113, and the charge of the exposed portion is removed to form an electrostatic latent image. The electrostatic latent image is developed as a toner image with toner attached thereto by the developing device 114. The toner image thus formed on the photosensitive drum 111 is conveyed to the transfer nip portion between the photosensitive drum 111 and the transfer roller 115 as the photosensitive drum 111 rotates in the direction of the arrow. The sheet S is supplied to the transfer nip portion by the above-described registration roller 110 so as to match the timing of the toner image. The toner image on the photosensitive drum 111 is transferred to the sheet S by the transfer roller 115.

  The fixing unit 103 includes a fixing roller 116, a pressure roller 117 that is in contact with the fixing roller 116 from below, and a paper discharge roller 118. In the image forming unit 102 described above, the sheet S on which the toner image is transferred from the photosensitive drum 111 is conveyed to the fixing unit 103, where the sheet S is formed by a fixing nip formed between the fixing roller 116 and the pressure roller 117. It is nipped and conveyed. At this time, the sheet S is heated and pressurized to fix the toner image on the surface.

  The paper discharge unit 104 includes a discharge port switching flapper 120, a transport roller 121, a paper discharge guide 122, a paper discharge roller 123, a paper discharge tray 124, and a delivery roller 125. The discharge switching flapper 120 can be switched between a sheet discharge position (not shown) and a sheet post-processing position (position shown in FIG. 1). When post-processing is not required for the sheet S after the toner image is fixed, the discharge port switching flapper 120 is disposed at the sheet discharge position, and is conveyed along the sheet discharge guide 122 by the conveyance roller 121. The paper is discharged in a face-down state on the paper discharge tray 124, that is, with the surface on which the toner image is formed facing downward. On the other hand, when post-processing is performed on the sheet S after fixing the toner image, the discharge port switching flapper 120 is switched to the sheet post-processing position shown in FIG. As a result, the sheet S is conveyed to the sheet post-processing apparatus 200 side by the delivery roller 125.

  A sheet re-feeding path 126 for use in forming an image on both the front and back sides of the sheet S is provided between the image forming unit 102, the fixing unit 103, and the upper sheet feeding cassette 105. ing. At the time of double-sided image formation, the sheet S on which the toner image is fixed on one side (front side) is switched back and then guided to the refeed path 126, from which the image forming unit 102 and the fixing unit 103 again. Then, image formation is also performed on the back surface. This is the end of the description of the image forming apparatus main body 100.

  Next, the configuration and operation of the sheet post-processing apparatus 200 will be described with reference to FIG.

  The sheet post-processing apparatus 200 includes a buffer unit 201 that can store up to two sheets conveyed one by one, a discharge unit 202 that discharges the sheet S stored in the buffer unit 201, and the discharge unit. The post-processing tray 203 on which the sheets S discharged from 202 are stacked, the aligning means 204 for aligning the sheets stacked on the post-processing tray 203 by moving them in the aligning direction, and the aligning means 204 A post-processing unit 205 that performs post-processing on the sheet S and a bundle discharge unit 206 that discharges the post-processed sheet S from the post-processing tray 203 are provided. Further, a discharge tray 207 on which the sheets S discharged from the bundle discharge unit 206 are stacked is provided on the downstream side of the bundle discharge unit 206 along the sheet S conveyance direction.

  Hereinafter, the buffer unit 201 will be described in detail.

  The buffer unit 201 includes an inlet roller 210, a first pass 211, a second pass 212, a switching flapper 213, a second pass roller 214, and a partition 215.

  Among these, the entrance roller 210 is disposed on the upstream side of the first pass 211 and the second pass 212, and the sheet S supplied by the delivery roller 125 of the image forming apparatus main body 100 is transferred to the first pass 211. Or it conveys to the 2nd path | pass 212. FIG.

  The first path 211 and the second path 212 are formed adjacent to each other, and both are partitioned by a partition wall 215 and a switching flapper 213. The first path 211 and the second path 212 are formed so as to be directed upward from below, and the middle part in the vertical direction is curved so as to protrude to the left in FIG. The first path 211 and the second path 212 are branched by a switching flapper 214 immediately downstream of the inlet roller 210, are separated by a partition wall 215, and merge at the most downstream side where the partition wall 215 is eliminated. . A second pass roller 214 for conveying the sheet S in the second pass 212 is disposed in the middle of the second pass 212. The second pass roller 214 rotates in synchronization with the entrance roller 210 described above. The switching flapper 213 guides the sheet S to the first path 211 when switched to the first position shown in FIG. 1, and moves the sheet S to the second path when switched to the second position shown in FIG. Lead to 212. As will be described in detail later, the buffer unit 201 can store (standby) a total of two sheets S, one for each of the first pass 211 and the second pass 212. ing.

  The discharge means 202 has an arm 216 whose tip side swings substantially vertically with respect to the base end portion 216a, and an upper discharge roller 217 that is rotatably supported by the tip portion of the arm 216, and this roller comes into contact with and separates from the arm 216. And a lower discharge roller 218. The discharge unit 202 discharges the sheet S conveyed via the buffer unit 201 on a post-processing tray 203 described below.

  The post-processing tray 203 includes a sheet stacking surface 220, a rear end abutting member 221, and a side end abutting member 222, which are integrally formed. Among these, the sheet stacking surface 220 is provided so as to be inclined so that the upstream side in the sheet conveying direction is positioned below. The rear end abutting member 221 is formed on the uppermost stream side of the sheet stacking surface 220 in the sheet conveying direction so as to protrude from the sheet stacking surface 220 in a wall shape at a right angle. The side end abutting member 222 (see FIG. 5A) is formed on the rightmost end side along the sheet conveying direction of the sheet stacking surface 220 so as to protrude in a wall shape at a right angle from the sheet stacking surface 220. . In the present embodiment, the rear end abutting member 221 and the side end abutting member 222 are described as constituting a part of an alignment unit 204 described later as an abutting member. Of course, even when these abutting members constitute a part of the post-processing tray 203, the substantial configuration of the present invention does not change.

  The aligning means 204 includes an upper returning roller 223 that is an upper aligning member (upper rotating body), a lower returning roller 224 that is a lower aligning member (lower rotating body), an upper arm 225 that is an upper contacting / separating mechanism, And a lower arm 226 which is a separation mechanism. The upper arm 225 is configured such that the distal end side swings substantially vertically with respect to the base end portion 225a, and an upper return roller 223 is rotatably supported at the distal end portion. The lower arm 226 is configured such that the distal end side swings substantially vertically with respect to the base end portion 226a, and a lower return roller 224 is rotatably supported at the distal end portion. As shown in FIG. 5A, in a state where the upper return roller 223 is in contact with the sheet S on the post-processing tray 203, the rotation shaft 223a is inclined with respect to the direction orthogonal to the sheet S conveyance direction. Yes. Further, in a state in which the lowering roller 224 is in contact with the sheet S on the post-processing tray 203, the rotation shaft 224a is inclined in substantially the same manner as the rotation shaft 223a with respect to the direction orthogonal to the sheet S conveyance direction. . The inclination direction is such that when the upper return roller 223 and the lower return roller 224 rotate and the outer peripheral surface thereof is rubbed against the sheet S, the sheet S is directed toward the rear end abutting member 221 and the side end abutting member 222. It is in the direction to carry. Further, in the abutting state, the lower return roller 224 is disposed downstream of the upper return roller 223 in the alignment direction. Accordingly, as described later, when aligning the two sheets S, the lower sheet S and the upper sheet S can be smoothly moved in the alignment direction. In other words, when the upper return roller 223 comes into contact with the upper surface of the upper sheet S of the two stacked sheets, the upper return roller 223 and the sheet stacking surface 220 sandwich the sheet, and the sheet stacking surface 220 regulates the downward movement of the upper return roller 223 and generates a conveying force for the upper sheet S by a reaction force from the sheet stacking surface 220. However, when the lowering roller 224 comes into contact with the lower surface of the lower sheet S, a notch (not shown) is provided in the sheet stacking surface 220 and comes into contact with the lower surface of the lower sheet S from this notch. The upper return roller 223 does not act together with the lower return roller 224 other than the buffered sheet, and only the upper return roller 223 frequently acts on the sheet. Therefore, the upper return roller 223 is cut to obtain a stable conveying force. Arranged avoiding the lack. For this reason, there is nothing that restricts the upward movement of the lower return roller 224, and the lower return roller 224 is such that the upper return roller 223 can serve as a reaction force applying means when the lower return roller 224 moves the sheet S in the alignment direction. It is arranged in the vicinity of. Therefore, the lower return roller 224 protrudes above the restriction position of the upper return roller 223. On the other hand, when the upper return roller 223 is disposed on the downstream side, the upper return roller 223 may interfere with the movement of the lower sheet S in the alignment direction.

  The upper discharge roller 217, the upper return roller 223, and the lower return roller 224 are driven in the vicinity of the base ends 216a, 225a, and 226a of the arms 216, 225, and 226 that support them. It is carried out via a belt by a driving pulley (not shown) to which rotation from a not shown is transmitted.

  As the post-processing means 205, for example, a stapler that binds a sheet bundle composed of a plurality of sheets S or a punch can be used. Any post-processing means 205 may be used as long as it involves processing for aligning the sheet S before post-processing.

  The bundle discharge unit 206 includes an upper bundle discharge roller 227 and a lower bundle discharge roller 228, and discharges the post-processed sheet bundle from the post-processing tray 203 onto the discharge tray 207. The upper bundle discharge roller 227 is configured to be able to contact and separate from the sheet S.

  A sheet discharge tray 207 is a tray on which the sheet bundle that has been stapled on the post-processing tray 203 and discharged by the bundle discharge unit 206 is stacked. The sheet discharge tray 207 is located above the image forming apparatus main body 100 and the image reading apparatus 300. It is arranged below.

  Next, FIGS. 2 (a), (b), (c), FIGS. 3 (d), (e), (f), FIGS. 4 (g), (h), (i), and FIG. 5 (a). ) And (b), details of the operation of the sheet post-processing apparatus 200 when a plurality of jobs (preceding job and succeeding job), that is, a stapling process for a sheet bundle composed of a plurality of sheets S is performed a plurality of times. Describe. 2A to 4I are front views of the sheet post-processing apparatus 200, and show a series of operations. 5A and 5B are top views in the vicinity of the post-processing tray 203. FIG. The operation of each roller, arm, and flapper described above is controlled by the control means (not shown) as will be described later.

FIGS. 2A and 5A show how the final sheet S _1L of the preceding job is discharged and stacked on the post-processing tray 203. FIG. At this time, the job between the succeeding job and the first sheet S ₂₁ is conveyed into the buffer unit 201 at a normal sheet interval. When the sheet S _1L is discharged onto the already-discharged sheet S (sheet bundle) on the post-processing tray 203, the separated returning roller 223 is pressed against the sheet S _1L from above and rotates. As a result, the sheet S _1L is moved in the alignment direction and is abutted against and aligned with the rear end abutting member 221 and the side end abutting member 222 (FIGS. 2B and 5B). The upper return roller 223 separates again after completion of alignment (FIG. 2C). During these operations, the upper bundle discharge roller 227 is in a separated state. In addition, when the sheets S are already stacked on the post-processing tray 203 as described above, the lowering roller 224 below the post-processing tray 203 is not necessarily operated.

When the separation of the upper return roller 223 is completed, the first sheet S ₂₁ of the subsequent job is conveyed through the first path 211, and the leading edge of the sheet exits between the upper discharge roller 217 and the lower discharge roller 218.

Next, when the trailing edge of the first sheet S ₂₁ of the succeeding job passes through the entrance roller 210, the upper discharge roller 217 is separated, and the leading edge of the first sheet S ₂₁ of the succeeding job reaches the end of the post-processing tray 203. The first path 211 is held in a state of protruding into the upper space. Further, when the switching flapper 213 is switched, a state where the second sheet S ₂₂ subsequent job can be introduced into the second path 212. Also, alignment of the sheet S _1L before the trailing edge of the first sheet S ₂₁ subsequent job exits the inlet rollers 210 and the binding process by the stapler 205 is terminated. (Fig. 3 (d))

Subsequently, a state where the first sheet S ₂₁ of the subsequent job is held, the second sheet S ₂₂ for the same succeeding job is transported to the second path 212, The upper bundle discharge in parallel roller 227 discharges the sheet bundle S ₁ of the preceding job on the paper discharge tray 207 by holding and conveying between the lower bundle delivery rollers 228 of the sheet bundle S ₁ of the preceding job (Fig. 3 (e)). When the preceding discharge of the job of the sheet bundle S ₁ of the discharge tray 207 is completed, the upper bundle delivery rollers 227 do apart again (FIG. 3 (f)). Incidentally, separation of the upper bundle discharge rollers 227, the leading end of the second sheet S ₂₂ of the succeeding job is only required to be completed before reaching this upper bundle discharge rollers 227.

The second sheet S ₂₂ of the succeeding job after the trailing edge of the sheet passes through the inlet roller 210 also continues to be conveyed by the second path roller 214 to the tip and the first sheet S ₂₁ are aligned. Thereafter, the upper discharge roller 217 leading edge of the second sheet _{S 22} at the timing of uniform with the tip of the first sheet _{S 21,} is pressed against the sheet _{S 22} (FIG. 4 (g)), the first sheet The sheet S ₂₁ and the second sheet S ₂₂ are overlapped and discharged onto the post-processing tray 203 (FIG. 4H). Further, the upper return roller 223 is completely separated at the sheet receiving position shown in FIG. 4G and the like before the sheets S ₂₁ and S ₂₂ are discharged onto the post-processing tray 203.

Thereafter, until the third sheet _{S 23} of the succeeding job enters the buffer means 201, by the upper sheet _{S 22} the upper return roller 223, also by the lower sheet _{S 21} returns the lower roller 224, respectively aligned It is moved in the direction and abutted against the rear end abutting member 221 and the side end abutting member 222 for alignment (FIGS. 4 (i) and 5 (b)).

  As described above, according to the sheet post-processing apparatus 200 of the present embodiment, an individual upturning roller is provided for each of the sheets S stacked on the post-processing tray 203 after being overlapped from the buffer unit 201. Since the sheet 223 can be moved in the aligning direction by the lowering roller 224 and aligned, the sheets S can be aligned reliably.

Incidentally subsequent third sheet S _23, without being stored in the first path 211 is discharged to the first path 211 as it passes to the sheet S in the preceding on the finishing tray 203, the upper back roller 223 Is matched by. Then, after the final sheet S2L is discharged and aligned, a stapling process is performed, and thereafter, the sheet is discharged onto the discharge tray 207 as a sheet bundle.

  Further, as described above, the upper return roller 223 is configured to come into contact with the sheet S in the vicinity of the lower return roller 224, so that the lower return roller 224 rubs against the lower sheet S to increase the conveying force. It acts as a reaction force applying means when applying. That is, since the lower return roller 224 generates a conveying force due to friction with respect to the lower sheet S, it is not necessary to provide a special reaction force applying means, and the configuration can be simplified correspondingly.

  Further, as described above, the lower return roller 224 is disposed downstream of the upper return roller 223 in the alignment direction of the sheet S, so that the lower sheet S is moved by the lower return roller 224 and the upper return roller 223 is also moved. Each upper sheet S can be smoothly moved in the alignment direction. When these rollers are arranged oppositely upstream and downstream, the lower return roller 224 protrudes upward from the restriction position of the upper return roller 223 and comes into contact with the sheet. When the sheet is moved in the alignment direction, the upper return roller 223 becomes a conveyance resistance, and the smooth movement of the lower sheet S is hindered. This is not the case with the present embodiment.

<Embodiment 2>
A second embodiment is shown in FIGS. 6, 7A, and 7B. In the present embodiment, a lateral alignment plate (width adjusting member) 230 is further added to the configuration of the first embodiment described above. Other configurations are the same as those of the embodiment, and thus redundant description is omitted.

  The sheet post-processing apparatus 200 according to the present embodiment protrudes upward from the sheet stacking surface 220 of the post-processing tray 203 and is also in the left-right direction on the sheet stacking surface 220 (the left-right direction in FIG. 7A: sheet conveyance direction). The horizontal alignment plate 230 is movable in the direction orthogonal to the horizontal direction.

When the last sheet S _1L of the preceding job are discharged onto the work tray 203 by upper discharge rollers 217, the sheet S _1L is pressed against the alignment direction is returned after having been separated from the roller 223 sheet S _1L ( The alignment is performed by moving the rear end abutting member 221 and the side end abutting member 222. In the present embodiment, the inclination of each of the rotation shafts 223a and 224a of the upper return roller 223 and the lower return roller 224 with respect to the sheet conveyance direction is set smaller than that in the first embodiment, and therefore, along the sheet conveyance direction. Moves greatly in the direction. When the rear end of the sheet S _1L is abutted against the rear end abutting member 221 and the alignment in the front-rear direction (direction along the sheet conveying direction) is completed, the alignment of the right end of the sheet S _1L is completed. Even so, the upper return roller 223 is immediately separated again. Then, the horizontal alignment plate 230 is moved to the right to start the horizontal alignment (FIG. 7A). Lateral alignment plate 230 is moved to the right is in contact with the left end of the sheet S _1L, moves the sheet S1L to the right, the abutment by aligning the right edge of the sheet S1L to abut the side edge member 222 Perform (FIG. 7B). After this alignment is completed, the horizontal alignment plate 223 begins to retract to the left, and before the next sheet S is discharged to the post-processing tray 203, it is completely retracted to the sheet receiving position (out of the sheet passing range). Yes.

  By adopting the configuration as described above, the upper return roller 223 can be separated from the sheet S at an earlier timing as compared with the first embodiment described above. 203 can be received above. That is, in addition to obtaining the same effect as in the first embodiment, it is possible to further improve productivity.

  The horizontal alignment plate 230 described above aligns not only the uppermost sheet S stacked on the post-processing tray 203 but also the sheet S in the left-right direction every time it is discharged from the buffer means 201 to the post-processing tray 203. Can be made.

  Therefore, even when the sheet S is not sufficiently aligned by the alignment operation when it is discharged onto the post-processing tray 203, or when the alignment of the intermediate sheet S is disturbed for some reason, Since matching can be performed again, more reliable matching can be performed. The same effect can be obtained when aligning the two sheets S stored in the buffer unit 201.

<Embodiment 3>
FIG. 8 shows a top view of the vicinity of the post-processing tray 203 in the third embodiment. In the present embodiment, the upper return roller 223 and the lower return roller 224 are configured such that the respective rotation shafts 223a and 224a face in a direction orthogonal to the sheet conveying direction.

In the present embodiment, the upper return roller 223 only abuts the rear end of the sheet S _1L against the rear end abutting member 221 and abuts the side end of the sheet S _1L against the side end abutting member 222. This is done by the lateral alignment plate 230.

  According to this configuration, in addition to obtaining the same effects as those of the above-described second embodiment, the sheet S can be aligned in the front-rear direction in a shorter time, and thus the productivity can be further improved. Become. The same effect can be obtained when aligning the two sheets S stored in the buffer unit 201.

<Embodiment 4>
FIG. 9 is a top view of the vicinity of the post-processing tray 203 in the fourth embodiment. In this embodiment, a plurality of upper return rollers 223 and lower return rollers 224 described in the first embodiment are provided. Note that the alignment operation of the sheet S is substantially the same as that of the first embodiment, and thus redundant description is omitted.

  As shown in FIG. 9, a plurality of upper return rollers 223a, 223b, and 223c are provided in the left-right direction, and lower return rollers 224a, 224b, and 224 that are paired (set) with these. These return rollers can be individually selected to be driven or not for each group by a control means (not shown).

  In the present embodiment, the paper type of the sheet S, that is, the nature (material), weight, thickness, or size of the sheet material can be detected in the conveyance path of the sheet S. (Not shown) is provided. Information about the paper type of the sheet S detected by the paper type detection unit is input to the control unit. Based on this information, the control means determines the set of return rollers to be driven.

  Specifically, for example, when aligning thick paper or large size paper, by increasing the number of return rollers to be driven, a sufficient sheet conveying force can be generated to perform reliable alignment. On the other hand, when aligning thin paper, only the pair of return rollers is driven in the vicinity of the abutting member 222 and the other group is not driven, so that it is likely to occur when the thin paper hits the abutting member. It is possible to effectively prevent buckling and rising of the end portion of the seat.

  In the first to fourth embodiments described above, the case where the roller-like upper return roller 223 and the lower return roller 224 are used as the upper alignment member (upper rotating body) and the lower alignment member (lower rotating body) has been described as an example. However, it is also possible to use a paddle or a belt instead.

  In the above description, the case where the image forming apparatus 10 includes the electrophotographic image forming unit 102 has been described as an example, but the present invention is not limited thereto. For example, it may have an electrostatic recording type or ink jet type image forming unit. However, the present invention can be suitably applied to an image forming apparatus having a high image forming speed, that is, a large throughput.

FIG. 2 is a longitudinal sectional view of the configuration of the sheet post-processing apparatus and the image forming apparatus main body according to the first embodiment viewed from the front side. (A), (b), (c) is a front view explaining operation | movement of the sheet | seat post-processing apparatus of Embodiment 1. FIG. (D), (e), (f) is a front view explaining operation | movement of the sheet | seat post-processing apparatus of Embodiment 1. FIG. (G), (h), (i) is a front view explaining operation | movement of the sheet | seat post-processing apparatus of Embodiment 1. FIG. (A), (b) is a top view explaining operation | movement of the sheet | seat post-processing apparatus of Embodiment 1. FIG. It is the longitudinal cross-sectional view which looked at the structure of the sheet | seat post-processing apparatus of Embodiment 2 from the front side. (A), (b) is a top view explaining operation | movement of the sheet | seat post-processing apparatus of Embodiment 2. FIG. FIG. 10 is a top view for explaining the operation of the sheet post-processing apparatus according to the third embodiment. FIG. 10 is a top view for explaining the operation of the sheet post-processing apparatus according to the fourth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 100 Image forming apparatus main body 102 Image forming part 200 Sheet post-processing apparatus 201 Buffer means 202 Discharge means 203 Post-processing tray 204 Alignment means 205 Post-processing means 206 Bundle discharge means 207 Discharge tray 221 Rear end abutting member ( Abutting member)
222 Side end butting member (butting member)
223 Upward return roller (upper alignment member: upper rotating body)
223a Rotating shaft 224 Lower return roller (lower alignment member: lower rotating body)
224a Rotating shaft 225 Upper arm (contact / separation mechanism)
226 Lower arm (contact / separation mechanism)
230 Lateral alignment plate (width adjustment member)
300 Image reading device S sheet

Claims (6)

In a sheet post-processing apparatus that performs post-processing on a conveyed sheet,
Buffer means for temporarily storing the conveyed sheet;
Discharging means for stacking and discharging two sheets stored in the buffer means;
A post-processing tray on which sheets discharged from the discharging means are stacked ;
An abutting member to which an end of the sheet on the post-processing tray is abutted and aligned;
A lower rotating body that applies a conveying force in an alignment direction toward the butting member by rubbing against the lower surface of the lower sheet of the two sheets discharged on the post-processing tray;
And a rotary body on which imparts conveyance force alignment direction towards the abutment member rubs the upper surface of the upper sheet of the two sheets discharged superimposed on said post-processing tray,
The abutting member includes a rear end abutting member that abuts the rear end of the sheet ejected on the post-processing tray, and a side end that abuts a side end in a direction orthogonal to the sheet ejection direction. An abutting member,
The lower rotating body and the upper rotating body have a rotating shaft inclined with respect to the sheet discharge direction, and rotate in contact with the sheet so that the sheet is abutted against the rear end abutting member and the side end abutting member. Abut against the member and align,
A sheet post-processing apparatus. In a sheet post-processing apparatus that performs post-processing on a conveyed sheet,
Buffer means for temporarily storing the conveyed sheet;
Discharging means for stacking and discharging two sheets stored in the buffer means;
A post-processing tray on which sheets discharged from the discharging means are stacked;
A rear end abutting member against which the rear end of the sheet ejected on the post-processing tray is abutted;
A side end abutting member against which a side end in a direction orthogonal to the sheet discharge direction is abutted;
The rear end abutting member having a rotating shaft extending in a direction perpendicular to the sheet discharge direction and slidingly rubbed with the lower surface of the lower sheet of the two sheets discharged on the post-processing tray. A lower rotating body that imparts a conveying force in the alignment direction toward
The rear end abutting member having a rotating shaft extending in a direction orthogonal to the sheet discharge direction and sliding on the upper surface of the upper sheet of the two sheets discharged on the post-processing tray. An upper rotating body that imparts a conveying force in the alignment direction toward
A width adjusting member that pushes a side edge of the sheet toward the side edge abutting member,
A sheet post-processing apparatus. The upper rotating body applies a reaction force to the sheet moved by the lower rotating body when the lower rotating body moves the sheet in the alignment direction;
The sheet post-processing apparatus according to claim 1 , wherein the sheet post-processing apparatus is provided. The lower rotating body and the upper rotating body are positioned so that the lower rotating body in contact with the sheet is positioned downstream of the upper rotating body in contact with the sheet in the alignment direction. Arranged,
The sheet post-processing apparatus according to claim 3 . A paper type detection means for detecting the paper type or size of the sheet discharged onto the post-processing tray;
A plurality of the upper rotating bodies;
A plurality of the lower rotating bodies;
Control means for selecting one to be operated from among the plurality of upper rotating bodies and the plurality of lower rotating bodies based on the detection result of the paper type detecting means,
Sheet post-processing apparatus according to any one of claims 1 to 4, characterized in that. In an image forming apparatus including an image forming unit that forms an image on a sheet, and a sheet post-processing device that performs post-processing on the sheet after image formation.
The sheet post-processing apparatus is the sheet post-processing apparatus according to any one of claims 1 to 5 .
An image forming apparatus.

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