JP2006076778A - Sheet handling device and image forming device using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet handling device capable of folding and overlapping sheets in order without causing trimming folding phenomenon by levitating a folding side part of a sheet. <P>SOLUTION: This sheet handling device is provided with a first paper folding roll means arranged in a sheet conveyance path, a folding sheet conveyance path arranged by branching from the sheet conveyance path and carrying out a folding sheet from the paper folding roll means, and a second paper folding roll means arranged by providing a sheet pressing means for pressing a folding sheet against a folding side in the folding sheet conveyance path. This sheet handling device is provided with a first conveyance means and a second conveyance means arranged across distance in the sheet conveyance path, a first folding roll means arranged between the first and second conveyance means, and a folding sheet conveyance path branched from the conveyance path to carry out a folding sheet from the first folding roll means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet processing apparatus that folds a sheet formed and discharged from an image forming apparatus such as a copying machine or a printer into two or three according to the bookbinding or filing state, and the sheet processing apparatus. The present invention relates to an image forming apparatus.

  In general, this type of sheet processing apparatus is used as an apparatus for folding a sheet discharged from a printing machine, a printer, or the like as a final process or carrying it out to a post-processing apparatus such as binding after the paper is folded. Many are connected to image forming devices such as printers, and are widely used as printing systems that consistently process everything from printing to bookbinding by folding the paper and then ejecting it directly or sending it to a post-processing device that performs binding such as stapling. Yes.

  Conventionally, this type of sheet processing apparatus has a pair of pressure-contact rollers arranged in a path for conveying a sheet, and folds the sheet into two by feeding the fold position of the sheet conveyed in the path between the pair of rollers. Further, the folded sheet is folded by a pair of rollers on the downstream side and folded into three or four. The sheet folding by such a sheet processing apparatus is performed by folding the sheet 1/2 position in half, folding the 1/3 position of the sheet in the same direction left and right, and folding the sheet in 1/3. The 1 / 3Z folding that folds the three positions in the opposite direction is adopted for the final use such as bookbinding and filing.

  Therefore, as an apparatus that can select such various folding methods, for example, Japanese Patent Application Laid-Open No. 2004-99199 (Patent Document 1) has been proposed. In the same document, a first folding roll is arranged in the conveyance path, a second folding roll is arranged in the carry-out path of the sheet folded by the folding roll, and the sheet folded by the first folding roll is second. A structure that is folded by a folding roll is disclosed. For example, when the sheet is folded in 1/3 or 1 / 3Z, the left 1/3 position of the sheet is folded with the first folding roll, and then the right 1/3 position of the sheet is folded with the second folding roll. The method of folding is taken.

Similarly, Japanese Patent Application Laid-Open No. 2003-160274 (Patent Document 2) and Japanese Patent Application Laid-Open No. 2003-118932 (Patent Document 3) disclose devices similar to those described above. In this way, the sheet processing apparatus folds the sheet on which the image has been formed by the image forming apparatus or the like and binds it into a bag binding, encloses the letter by folding in 1/3, or folds it by 1 / 3Z folding, etc. Since paper folding is performed according to the final purpose and the structure can be relatively simple and compact, a method of folding in the order of first folding and second folding with three roller pairs is widely known.
JP 2004-99199 A JP 2003-160274 A

  As described above, when the sheet is folded in three or more by the first and second folding rolls sequentially arranged in the conveyance path, the first folding side is folded on the first folding side. The problem of folding the edge of the fold side occurs. This is because the folding edge of the sheet is lifted in the process of folding the sheet with the second folding roll while the leading edge of the sheet folded by the first folding roll is regulated by a stopper, a pair of conveying rollers, etc. This is because the rear end of the sheet that is folded up entrains it and folds it into a folded ear. In particular, when the first and second rolls are composed of three rolls, or when the roll diameter is increased, this ear fold phenomenon also occurs frequently.

  Conventionally, in order to solve such a problem, a method of making a crease by making a folding plate enter a folding roll as in the above-mentioned Patent Document 1 has been tried, but the paper folding speed of the apparatus is lowered and the structure is complicated. There was a drawback.

  The present invention has a simple structure, and when folding a sheet such as a tri-fold of a sheet, the folded side of the sheet that has been folded first floats up, and the sheet can be folded in an orderly manner without causing the phenomenon of ear folding An object of the present invention is to provide a processing apparatus and an image forming apparatus using the same.

The present invention adopts the following configuration in order to solve the above problems.
A first folding roll means arranged in the sheet conveyance path, a folded sheet conveyance path branched from the sheet conveyance path and carrying out the folded sheet from the folding roll means, and folded in the folded sheet conveyance path. A sheet pressing unit that presses the sheet toward the folding side is provided, and a second folding roll unit is provided. Further, the first and second conveying means arranged at a distance from the sheet conveying path, the first folding roll means arranged between the first and second conveying means, and the conveying path A folded sheet conveying path for branching and carrying out the folded sheet from the first folding roll means is provided, and further, a leading edge folding portion of the sheet from the first folding roll means arranged in the folded sheet conveying path A stopper means for restricting abutment, and a rear end edge of the sheet whose leading edge is regulated by the stopper means is arranged in the conveyance path so as to be folded in the same direction as the leading edge folding portion, and the second folding roll means, Further, sheet pressing means for pressing the leading edge folding portion of the sheet guided to the folding roll means in the overlapping direction is provided.

  The sheet pressing means is configured to be movable between a position retracted from the folded sheet conveying path and an operating position for pressing the sheet end in the overlapping direction in the folded sheet conveying path. And driving means for moving between the operating positions. The first and second paper folding roll means are composed of three rollers that are in pressure contact with each other, and a first folding roll means that folds and carries out the sheet from the conveyance path with the first roll and the second roll that are in pressure contact with each other. And a second folding unit configured to fold and carry out the sheet from the folded sheet conveyance path by the first roll and the third roll, and the sheet folded by the first folding roll unit is biased in the folding direction. It has a curved part to make it close.

  An image forming unit that forms an image on the sheet, a paper folding unit that folds the sheet from the sheet discharge port of the image forming unit, and post-processing such as stapling and punching on the sheet from the discharge port of the paper folding unit. And a post-processing unit. In the paper folding unit, a stacker for storing the folded sheets via the path switching unit and a sheet discharge path for conveying the folded sheets to the post-processing unit are connected to the folded sheet conveying path.

  In the present invention, sheet folding means for pressing the folded sheet toward the folding side is provided in the folded sheet conveying path for carrying out the folded sheet from the first folding roll, and the folded sheet is guided to the second paper folding roll. Therefore, when folding the sheet with the second folding roll, there is no possibility that the folded side portion of the sheet folded first will be lifted up and cause ear folding. Further, the sheet pressing means is configured to be movable between a position where the sheet presser is retracted from the path and a position where the sheet is pressed in the path, and when the sheet leading edge enters the path, the sheet in the path is placed at the retracted position. When the sheet is wound by the second folding roller, it is not hindered when the leading edge of the sheet enters the path by being positioned by the driving means at the pressing position.

  The present invention will be described in detail below based on the preferred embodiments shown in the drawings. FIG. 1 shows an image forming apparatus using the sheet processing apparatus of the present invention, FIG. 2 is an explanatory diagram showing a paper folding procedure (paper folding mode) in the sheet processing apparatus, and FIG. 3 is an overall configuration diagram of the sheet processing apparatus Respectively.

  First, an overall system of an image forming apparatus using the present invention will be described. FIG. 1 illustrates an image forming unit 100, a sheet processing unit 200 (hereinafter referred to as a paper folding unit) for folding an image sheet carried out from the unit, and post-processing such as stapling on the sheet carried out from the paper folding unit 200. 2 shows an image forming apparatus A including a post-processing unit 300 that performs the processing. The image forming unit 100 has a built-in printing unit such as an inkjet, electrostatic drum, or offset drum, and is sent from a data forming unit such as a copying apparatus or a computer that prints an image read by the scanner unit 120 on a sheet by the printing unit. The printer is configured to print image data on a sheet by a printing unit.

  The paper folding unit 200 is provided with a paper folding mechanism that folds the sheets formed and sequentially conveyed by the image forming unit 100 into two or three folds, and binds the sheets after image processing or according to use conditions such as filing Paper folding process. The post-processing unit 300 is connected to the paper discharge port of the paper folding unit 200, receives a sheet after paper folding processing or a sheet that is not subjected to folding processing from the paper discharge port, and performs post-processing such as stapling and punching, The sheet is stored on the final delivery stacker.

  Various print processing systems as described above are widely known, and an example of an image forming unit and a post-processing unit will be described with reference to FIG. The illustrated image forming unit 100 shows the configuration of the copying machine, and includes a document feeding unit (ADF) 110 that feeds an original document, a scanner unit 120, and an image forming unit 130. Therefore, the document feeding unit 110 sequentially separates a series of documents placed on the stacker one by one and feeds them to the platen of the scanner unit 120. After the scanner unit 120 reads the document, the document is stored in the sheet discharge stacker. It is configured as a normal document feeder.

  The image data read by the scanner unit 120 is subjected to image processing and sent to the image forming unit 130. The image forming unit 130 irradiates and outputs laser light onto the photosensitive drum 140 in accordance with the received image signal. By this laser light irradiation, an electrostatic latent image is formed on the photosensitive drum 140. The electrostatic latent image is developed into a toner image by the developing device 141 and is transferred by the transfer charger 142 to a sheet such as paper fed from the paper feed cassette 150a or 150b. The paper PA onto which the toner image has been transferred is subjected to a fixing process by the fixing device 143. The fixed paper PA is discharged to a paper folding unit 200 connected by a main body discharge roller 160.

  At this time, discharge of the paper PA is detected by the main body discharge port sensor 161, and a main body discharge signal ES is transmitted from the main body CPU to the paper folding unit control unit 290 of the paper folding unit 200. The paper folding unit control unit 290 of the paper folding unit 200 takes the operation timing based on the main body paper discharge signal ES from the image forming unit 100, and uses the size signal DS and the folding mode signal FS for the sheet conveyed to the sheet carry-in port 210. Judge the processing.

  The paper PA taken in from the sheet carry-in roller 211 at the entrance of the paper folding unit 200 is routed by a carry-in gate 240 provided immediately after the sheet carry-in roller 211. When the folding process is not designated, the sheet folding unit 200 passes through the fourth conveyance path 253 formed by the pinch roller unit 230 formed by the pinch rollers 231 and 232 at the top of the sheet folding unit 200 and the sheet post-processing is performed. It is sent to a unit 300 (hereinafter referred to as a post-processing unit).

  When the folding process is designated, the sheet is transported to the first transport path 250 to be taken into the paper folding unit 200, and the information of the size signal SS and the folding mode signal FS is used to perform the 1/3 in-fold process and the 1 / 3Z-fold process. The folding process selected from either the process or the 1 / 4Z folding process is performed. At this time, if the 1/3 in-fold process is selected, the sheets are stored and stacked in the folded sheet storage box 280 in the paper folding unit 200. In the case of other folding processes, after the folding process, it passes through the third transport path 252 and joins the fourth transport path 253 and is sent to the post-processing unit 300 for further binding processing, punching processing, and the like.

  The post-processing unit 300 is installed by being connected to the carry-out port of the paper folding unit 200, and performs post-processing such as stapling, punching holes, and stamping the sheet from the paper folding unit 200. The structure is such that a sheet carry-in port is provided at the sheet carry-out port of the paper folding unit 200, and a post-processing mechanism (stepler) 304 for performing post-processing on the sheet is provided in a conveyance path 302 between the carry-in port and the sheet storage stacker 301. Deploy. The illustrated example illustrates the case where stapling is performed using a stapler as a post-processing mechanism. A staple tray 303 for stacking and holding sheets and a stapler 304 for performing staple binding on a sheet bundle stacked on the tray are arranged on the conveyance path 302.

  Various types of the stepper 304 are already known. Any of the present invention can be used, and a gluing device for gluing one side edge of the sheet instead of the stepper 304 also punches the sheet. A punching device or a stamping device that applies a predetermined marking to a sheet is also known, and these are incorporated into the conveyance path 302 according to the specifications of the post-processing unit 300. Incidentally, the reference numeral 305 in the figure denotes a second storage stacker that stores folded sheets via a paper discharge path 306 when there is no need to post-process the sheets from the paper folding unit 200.

  Next, the paper folding unit 200 will be described. First, in the image forming apparatus described with reference to FIG. 1, the forms of paper folding that are normally required are 1/2 fold, 1 / 3Z fold, 1/3 fold, and 1 / 4Z fold. Each form of the paper folding will be described.

(1/2 fold)
The sheet carried out from the image forming unit 100 is folded at a fold at a half position in the conveyance direction. In this way, a bag-bound document can be created by folding the center half position of the sheet, and stapling or glue-binding the folded end of the folded sheet. It is also used for organizing various documents, such as filing by punching a folded sheet. In this case, a half position of the sheet carried out from the image forming unit 100 is folded by a folding roll disposed in the conveyance path. Accordingly, the conveying path requires a pair of sheet folding rolls and a regulating means for determining the fold position based on the leading edge or the trailing edge of the sheet.

(Trifold in 1/3)
The front end side and the rear end side of the sheet are folded in the same direction at a position where the sheet is 1/3 in the conveyance direction length. As shown in FIG. 2A, the 1/3 position on the leading end side in the sheet conveyance direction is folded, and the 1/3 position on the trailing end side of the sheet is overlaid on the folded piece. The sheet folded in this way is suitable for use as a letter enclosed in an envelope. Therefore, it is necessary to arrange the first folding roll in the conveyance path, the folded sheet carry-out path for carrying out the sheet folded by the folding roll, and the second folding roll in the folded sheet carry-out path.

(1 / 3Z folding)
The leading end side and the trailing end side of the sheet are folded in the opposite direction to 1/3 of the sheet conveying direction length. As shown in FIG. 2B, the front end side 1/3 position and the rear end side 1/3 position in the sheet conveying direction are folded to the opposite sides. The sheet folded in this way is used, for example, enclosed in an envelope as a direct mail. Therefore, it is necessary to arrange the first folding roll on the upstream side and the second folding roll on the downstream side in the transport path.

(1 / 4Z folding)
As shown in FIG. 2C, the center of the sheet conveyance direction is folded in half at the 1/2 position, and then the piece folded in two is further folded in half on the opposite side at the 1/2 position. Sheets folded in this way are filing by sequentially stapling or punching a series of documents stacked one after another. As a result, large and small sizes, for example, A3 size documents can be aligned and bound to A4 size documents.

Next, a detailed description of the paper folding unit shown in FIG. 1 is shown in FIG.
The paper folding unit 200 includes a sheet carry-in port 210 for taking in the paper PA discharged from the image forming unit 100, a sheet carrying roller 211 for carrying the taken-in paper PA, and pinch rollers 231 and 232 at the entrance. There is a pinch roller unit 230 constituted by There is a carry-in gate 240 immediately after the pair of rollers on the sheet carry-in side, and the conveyance path is switched depending on whether or not folding processing is performed.

  When the folding process is not performed, the carry-in gate 240 is not switched and the paper PA is sent to the post-processing unit 300 through the horizontal fourth transport path 253 formed by the pinch roller unit 230 and the transport roller 211 facing the PA. Further, the pinch roller unit 230 has a hinge structure and can be opened and closed upward to cope with troubles such as a paper transport jam.

  When the folding process is selected, the carry-in gate solenoid SL1 is turned on and the carry-in gate 240 is switched, and the sheet PA is conveyed to a sheet conveyance path 250 (hereinafter referred to as a first conveyance path) for performing the folding process. On the first conveyance path 250 after passing through the carry-in gate 240, there is an entrance sensor SS1 that detects the carried-in paper PA. When the sheet is detected by the entrance sensor SS1, the folding drive motor M2 for performing the folding process starts to be driven. Downstream of the entrance sensor SS1, there is a roller pair of a carry-in roller 212 and a pinch roller 233 which are first transport means for taking the paper PA into the paper folding portion, and a path sensor for paper detection and paper jam detection before the roller pair. There is SS2. Further, a sheet trailing edge stopper 242 (regulating means) described later is provided downstream of the roller pair.

  Further, a first roll 214, a second roll 215, and a third roll 216 are disposed downstream of the first transport path 250, and between the first roll 214 and the second roll 215 and between the second roll 215 and the third roll 216. Are in pressure contact and have a space formed between the pressure contact rollers and the conveyance path. A fold 1 loop forming portion 255 is formed between the first conveying path 250 and the pressure contact rollers of the first roll 214 and the second roll 215, and a neutralizing brush 260 is installed in this portion corresponding to the leading portion of the paper folding portion. The static electricity on the paper surface that affects the charged paper folding generated on the main body is removed.

  Further, a folded sheet conveyance path 251 (hereinafter referred to as a second conveyance path) and a second roll, which are downstream conveyance paths on the opposite side through the pressure-contact rolls of the first roll 214 and the second roll 215 (first folding roll means). 215, a folded two loop forming portion 256 is formed between the pressure contact rollers of the third roll 216 (second folding roll means). In addition, there is a pair of registration SB rollers 213 and pinch rollers SB234 on the downstream side of the folding 1 loop forming section 255 of the first conveyance path 250, and a pre-registration sensor SS3 immediately before the pair of rollers, and a post-registration immediately after the roller pair. A sensor SS4 is arranged to perform registration and skew correction of the transport paper PA. Further, it is a conveyance path that has a folded one-sheet rear path 254 downstream thereof and stores the sheet when processing a long sheet in the conveyance direction.

  In the second transport path 251, the paper in a folded state is transported between the pressure rollers of the first roll 214 and the second roll 215, and a position variable described later is provided near the most downstream portion of the second transport path 215. A folding reference stopper 243 (abutting stopper member) which is an abutting stopper made of a lever member is disposed. This lever member has a pivot point on the curvature center side of the curved guide member, and is rotated by a predetermined angle by a stopper moving motor M4.

  Therefore, the position of the folding reference stopper 243 can be adjusted by the stopper moving motor M4 during the second transport pass. A sheet pressing guide 244 described later is provided on the second conveyance path 251 in the vicinity of the folding two-loop forming unit 256, and swings to prevent edge folding due to floating of the paper edge when folding the paper. Further, a folded sheet detection sensor SS5 is provided on the downstream side in the vicinity of the sheet pressing guide 244, and monitors a paper jam or the like at the time of paper folding. The second conveyance path 251 is configured by a curved guide member that is curved as illustrated, and is configured by a plate-shaped member that is curved in a direction in which folded sheets are stacked.

  The second paper fold is conveyed by nip conveyance between the pressure rollers of the second roll 215 and the third roll 216, and immediately after that, a fold portion is formed so as to make a crease with the roller pair of the discharge roller 217 and the discharge pinch roller 235. Pressurize and convey. After the folding process is completed, the sheet carry-out path 252 (hereinafter referred to as the third conveyance path) is transferred to the post-processing unit 300 by each roller pair of the conveyance rollers 218, 219, 220, 221, 222, and 223 and the conveyance pinch roller 236. Be transported.

  A storage gate 241 is provided immediately after the transport roller 218 on the third transport path 252, and a sheet that has been subjected to the inner folding process and the 1 / 3Z folding process is selectively placed in a folded sheet storage box 280 that is installed in the lower part thereof. Guide and stack. Further, the storage gate 241 has a folded portion discharge sensor SS6, and confirms that the storage gate 241 has passed through the storage gate 241 and has been transported and stored. A full detection sensor SS7 is provided in the upper part of the folded sheet storage box 280, and the storage fullness is detected via the folded sheet press flapper 282. Further, the folded sheet storage box 280 is detachable with a guide rail provided on the paper folding unit side. Further, a trapezoidal protrusion is provided at one end of the rack for rotating the folded sheet pressing flapper 282, and when the folded sheet storage box 280 is attached / detached, the folded sheet storage box 280 of the paper folding unit is attached to the end of the attaching / detaching opening. The folded sheet pressing flapper 282 is rotated and retracted into the folded sheet storage box 280 by applying the trapezoidal projection.

  Sheets subjected to folding processing other than the 1/3 inner folding and 1 / 3Z folding processing pass through the storage gate 241 and are conveyed by each pair of conveyance rollers and conveyance pinch rollers, and face the pinch roller unit 230. The sheet is joined to the horizontal fourth conveyance path 253 formed by the sheet conveyance rollers 211 to be conveyed to the post-processing unit 300. Immediately after the merge point of the fourth conveyance path 253, there is a sheet discharge sensor SS8, which monitors the conveyance of the folded paper, and the paper folding device control unit 290 transmits a paper detection signal to the post-processing unit 300.

  A drawer upper rail 201 and a drawer lower rail 202 are installed at appropriate positions above and below the paper folding unit 200 so that a mechanism including a paper transport path can be pulled out for maintenance. A paper folding device control unit 290 including a driving power supply unit for the paper folding unit 200 is housed in the lowermost part of the paper folding unit 200. Furthermore, a caster that supports and moves the weight of the apparatus is attached to the lowermost part of the paper folding unit exterior.

<Description of stopper structure>
(Registration SB roller)
The registration SB roller 213 (tip regulating means) is independently driven by a registration motor M3 formed of a pulse motor, and is driven separately from the other transport rollers. A pinch roller 234 is pressed against the registration SB roller 213 and nips the sheet, but can be arbitrarily stopped by a registration motor M3. If the registration SB roller 213 is in a stopped state when the sheet is taken in and conveyed by the carry-in roller 212, the leading end of the sheet is stopped when it reaches the pressure contact line between the registration SB roller 213 and the pinch roller 234, and the registration SB The roller 213 functions as a paper stopper. Also, when the registration motor M3 stops while the pair of rollers of the registration SB roller 213 and the pinch roller 234 is conveying the sheet, the conveyance of the sheet stops at the nip point, and the registration SB roller 213 functions as a sheet stopper as described above. To do. At this time, a reliable paper stopper can be obtained by exciting the registration motor M3 which is a pulse motor.

(Seat rear end stopper)
This will be described with reference to FIGS. FIG. 8B is a partial cross-sectional view of the sheet trailing edge stopper 242 provided in the first conveying path 250, and the sheet trailing edge stopper 242 is a swingable triangle having a rotation center on the upstream side outside the conveying path 250. A part of the path guide surface is cut out with a shaped lever so that it can be moved back and forth in the transport path. The sheet trailing edge stopper 242 is subjected to its own weight moment by the position of the center of gravity of the sheet trailing edge stopper 242 so as to be always located in the conveyance path. The position of the sheet trailing edge stopper 242 is downstream of the carry-in roller 212. When the sheet is fed by the carry-in roller 212, the sheet leading edge advances along the lever slope of the sheet trailing edge stopper 242 while pushing the lever out of the path guide. . When the trailing edge of the sheet passes through the sheet trailing edge stopper 242, the sheet trailing edge stopper 242 returns to the conveyance path by its own weight moment. At this time, as shown in FIG. 8B, one side of the triangular sheet trailing edge stopper 242 is in a posture orthogonal to the conveyance direction of the conveyance path.

  Therefore, after the sheet trailing edge passes through the sheet trailing edge stopper 242, the sheet trailing edge stopper 242 functions as a sheet stopper when the registration SB roller 213 reversely rotates and conveys the sheet in the reverse direction. Further, the sheet rear end stopper 242 is unitized as shown in FIG. 8A, and is fixed to the path guide with a variable screw so that the stopper position can be adjusted.

(Fold standard stopper)
The function and configuration of the folding reference stopper will be described with reference to FIG.
In the folding process, the first folding process is performed by the first roll and the second roll, and the nip is conveyed to the second conveyance path 251 with the folded portion at the head for the second folding process. At this time, the folding reference stopper 243 variably disposed on the downstream side of the second conveyance path 251 hits the folding portion, prevents the conveyance of the sheet, and forms a loop in the folding 2 loop forming unit 256 to form the second roll and the second roll. Prompt the second folding process with three rolls. The function of the folding reference stopper 243 is to change the position to determine the second folding position, and to enable a plurality of folding modes such as an inner three-folding process, a 1 / 3Z folding process, and a 1 / 4Z folding process. Is to do.

  As shown in FIG. 10, the folding reference stopper 243 is directly driven by a stopper moving motor M4 comprising a pulse motor, and the stopper position is a folding reference home detection sensor for detecting the rotation of the mask plate coaxially fixed to the motor shaft. The HS1 is arranged to determine the initial position, and the movement amount from the initial position is controlled by pulse counting.

<Sheet press guide>
This will be described with reference to FIGS.
FIG. 7A shows an entrance portion of the transport path on the folding roll side in the cross section of the second transport path 251. As shown in FIG. 7B, the sheet pressing guide 244 is rotatably supported by a support shaft fixed to one side of the second conveyance path guide 251. When the pressing solenoid SL4 is turned ON, the sheet pressing guide 244 is rotated. Return to the spring force with the presser foot OFF. The sheet presser guide 244 has a plurality of presser rollers that are rotatable in the paper transport direction, and reduces the transport resistance when the paper is pressed as much as possible.

  In addition, as shown in FIG. 7A, the sheet pressing guide 244 is normally at a position for guiding the first folded paper to the second transport path 251, and the first folding is performed when the second folding process is performed. The sheet pressing guide 244 reverses from the first roll side to the third roll side and presses the sheet in order to prevent the ear fold or the like from being caught due to the floating of the processed sheet end surface. The reversal timing is that the presser solenoid SL4 is actuated after a lapse of a predetermined time individually set in the folding mode from the time when the folded portion is detected by the folded sheet detection sensor SS5.

  In particular, when the sheet is folded in the 1/3 inner fold or the sheet having a small sheet length is folded, the sheet is controlled to move from the retracted position outside the path to the operating position in the path. This control is held at the retracted position when the sheet enters the second transport path, and moves from the retracted position to the operating position after the leading edge of the sheet hits the butting stopper member. At this operating position, the sheet pressing means presses the sheet folded by the first folding roll means in the folding direction.

<Description of transport drive system>
FIG. 4 shows a conveyance drive system of the paper folding unit 200, which will be described below.
(Upper conveyance drive system)
The fourth conveyance path 253 that is the upper conveyance system is an independent conveyance system that bypasses the folding processing conveyance system of the paper folding unit when the folding processing is not designated. Sheet conveyance rollers 211 are arranged before and after the conveyance path, and are driven and transmitted by a timing belt by a single conveyance motor M1. However, the folding process is performed, and if there is further post-processing, the folding process is performed, and then the fourth transport path 253 is joined to the post-processing unit 300.

(Folding part conveyance drive system)
The folding part conveyance drive system is driven by a folding drive motor M2 which is a brushless motor except for a registration SB roller drive described later. The drive transmission is transmitted from a pulley P1 integrated with the M2 gear G7 fixed to the folding drive motor shaft to a third pulley P2 integrated with the third roll gear G6 via a timing belt, and the third roll gear G6 and the second roll gear. G5 and the first roll gear G4 and gear transmission are driven. The M2 gear G7 fixed to the folding drive motor shaft drives the carry-in roller 212 via the first gear G1, the second gear G2, and the third gear G3.

  The first transmission gear G8 is driven to transmit through the timing belt from the first pulley P3 integrated with the first roll gear G4 to the first transmission gear pulley P4 integrated with the first transmission gear G8 to reverse the rotation direction. To the second transmission gear G9 to drive the conveying roller 219 on which the second transmission gear G9 is coaxially fixed. A transport roller pulley P6 is coaxially fixed to the transport rollers 218, 219, 220, 221, 222, and 223 and the carry-out roller 217, and the transport roller 220 in the third transport path 252 is coaxially fixed to the transport roller 219. , 221, 222, and 223 are sequentially transmitted to the belt. Further, the belt branches from a conveyance roller pulley P6 coaxially fixed to the conveyance roller 219, and belt drive is transmitted to the carry-out roller 217 and the conveyance roller 218 sequentially.

(Registration SB roller drive system)
The registration SB roller drive transmission mechanism will be described with reference to FIGS.
As described above, the registration SB roller 213 is independently driven by the registration motor M3 for skew correction and folding processing of the conveyance paper, and is driven separately from the other conveyance rollers. Further, as shown in FIG. 11A, a saw-tooth pawl clutch mechanism is employed for driving transmission from the registration motor M3 to the registration SB roller 213. One gear-integrated ratchet G10 of the pawl clutch is integrally fitted and positioned with respect to the resist SB roller shaft 261 integrally with the transmission gear directly connected to the resist motor M3, and the other shaft fixing ratchet G11 of the pawl clutch is The resist SB roller shaft 261 rotates integrally through a parallel pin, and an axial elongated hole for fitting the parallel pin is provided in the shaft fixing ratchet, thereby enabling the minimum axial movement necessary to disengage the mesh. . When the registration motor M3 is rotated forward and backward in this state, the clutch pawl shape is sawtooth, so that the drive can be transmitted in one direction as it is. However, in the opposite rotation, the axial force acts and the clutch pawl is released.

  For this reason, a pressing spring 263 is inserted into the registration SB roller shaft 261 in the direction in which the shaft fixing ratchet is engaged, and the spring is urged. Can be turned on and off. When the registration SB roller 213 mainly feeds the paper, the ratchet solenoid SL5 is turned on and the rear surface of the shaft fixing ratchet is engaged with the ratchet pressing lever 262.

  The functions of the registration SB roller 213 include: (1) a paper tip abutting roller function for skew correction, (2) a forward / reverse conveyance function at the time of three-fold folding within 1/3, and (3) at the time of 1 / 3Z folding processing And (4) perfect followability during fold roll nip conveyance (because it does not become a load on the fold roll).

  Since the above function has the function (4) in particular, the above mechanism is employed. That is, when the folding process is performed in a state where the sheet is nipped by the registration SB roller 213, in order for the folding function to be performed normally, after the sheet is delivered to the folding roll, the folding roll mainly becomes the registration SB roller 213. Needs to follow the sheet as it is conveyed by folding rolls. For this reason, as shown in the figure, a serrated pawl clutch mechanism is employed, and when the roll nip is conveyed while the sheet is nipped by the registration SB roller 213, the ratchet solenoid SL5 is turned off and the folding roll conveyance force causes the clutch to move. The engagement is released and the resist SB roller 213 is idled. In order to satisfy the function (4), the pressure contact of the pinch roller 234 on the other side of the registration SB roller 213 may be released without using a clutch, but it is only necessary to obtain certainty at the release timing or the like.

<Loading roller configuration>
The mechanism shown in FIG. 5 is used for the pressure contact and separation of the conveying rollers. There is a roller pair of a carry-in roller 212 and a pinch roller 233. The pinch roller 233 is rotatably supported by a pinch lever 264 that is swingably fitted to a pinch shaft 267 fixed to an apparatus frame (not shown). The spring is in pressure contact with the carry-in roller 212. A pressure arm 265 supported by a shaft 267 is engaged with the pinch lever 264, and the pressure arm SL 265 is configured so that the pressure solenoid SL 3 presses the pinch roller 233 against the driving roller (loading roller) 212. It is made to act. In particular, when the front end of the paper is registered, the pressure solenoid is turned ON, and the pinch roller 233 is pressed and pressed through a pressure arm 265 that is swingably fitted to and supported by the pinch shaft 267 to increase the conveying force, thereby increasing the conveying force. Allows the formation of loops.

  In addition, it is necessary to separate the pinch roller 233 from the carry-in roller 212 in order to make the paper free at the time of paper skew correction after registration and after the paper is transferred from the carry-in roller 212 to the folding roll. For this reason, the separation solenoid SL2 is turned on, and the pinch lever is rotated in the direction in which the pinch roller 233 is separated by the separation arm 266 that is swingably fitted and supported by the separation arm shaft 269 fixed to the conveyance frame (not shown).

  On the other hand, the pinch lever 264 is provided with a separation arm 266 and a separation solenoid SL2 attached thereto in a direction in which the pinch roller 233 is separated from the drive roller 212 around the shaft 267 (counterclockwise in the drawing). Accordingly, the pinch roller 233 is pressed against the driving roller 212 by this biasing spring, and strongly presses when the pressure solenoid SL3 is actuated to reliably convey the sheet, and when the separation solenoid SL2 is actuated, the pinch roller 233 is actuated. Is separated from the driving roller 212 and the sheet is in a free state.

  In this way, when the pinch roller is pressed and separated, the separation solenoid and the pressure solenoid are used so that the sheet conveyed between both rollers is strongly pressed and conveyed by the action of the pressure solenoid so as not to slip. When the separation solenoid is separated, the separation solenoid is separated from a relatively weak biasing spring, so that the separation solenoid can be made small.

<Folded sheet storage box full detection mechanism>
The configuration of the full detection mechanism of the folded sheet storage box will be described with reference to FIG.
A folded sheet press flapper 282 is fixedly supported on a flapper shaft 283 that is rotatably fitted and supported on the folded sheet storage box wall above the folded sheet storage box. A rack 286 is arranged on the rear side of the folded sheet storage box, and a flapper gear 284 fixed and supported by a parallel pin on the flapper shaft 283 is rotated via the pinion gear 287 by the movement of the rack 286, and the folded sheet pressing flapper 282 is rotated. Rotates counterclockwise and comes into contact with the stack paper surface. When stacking sheets, the end of the sheet opposite to the folded crease is on the flapper shaft side, and the end of the sheet opens to the top side of the stack and has a floating shape. At this time, the folded sheet pressing flapper rotates counterclockwise from the sheet fold side to the sheet end side to eliminate the influence of floating. The parallel pin grooves of the flapper gear 284 have a play in the rotation direction, and a flapper gear spring 285 is incorporated so as to absorb the play, thereby preventing the folded sheet pressing flapper 282 from being bent when contacting the stack sheet surface. .

  A flapper solenoid SL7 is disposed and fixed on a device frame (not shown) facing the rear side of the folded sheet storage box 280. When the flapper solenoid SL7 is turned on, the rack moves via the flapper SOL lever and the folded sheet presser is moved by the above movement. The flapper 282 rotates to perform a full detection operation. A sensor mask plate 289 is fixed to the flapper shaft 283, and the full detection sensor SS7 is disposed opposite to the flapper shaft 283. When the full detection is performed, the full detection sensor is shielded from light. The sheet pressing flapper 282 is attached to the side for pressing the free end side of the sheet.

<Description of paper folding unit operation>
The operation of the paper folding unit will be described with reference to FIGS.
As a basic operation, for the paper output and discharged from the main body for which the paper folding process is designated, according to the designated folding mode, the above-described one-third in-fold, 1 / 3Z-fold, 1 / 4Z Perform the folding process.

(Initial operation)
When the main body power is turned on, the power supply on the paper folding unit side is also turned on, the state of actuators such as sensors and solenoids is compared with preset initial values, and communication is performed with the main body side to perform initial operation if necessary. Simultaneously with the above initial confirmation, the conveyance motor M1 and the folding drive motor M2 start to drive.

(Capture paper)
When a sheet is conveyed from the main body to the sheet carry-in entrance 210 of the paper folding unit 200, information on the paper discharge signal ES, the size signal DS, and the folding mode signal FS is sent from the main body CPU to the paper folding device control unit 290 of the paper folding unit. Entered. Based on this input information, the carry-in gate 240 immediately after the sheet carry-in entrance of the paper folding unit guides to the first conveyance path 250 into the paper folding unit.

(Paper registration processing)
The paper PA transported to the first transport path 250 is detected by the entrance sensor SS1 and the path sensor SS2, the transport state is monitored and further fed by the carry-in roller 212, and the leading edge of the paper is detected by the pre-registration sensor SS3. After the pre-registration sensor SS3 is turned ON, the carry-in roller 212 is further driven for a predetermined time in a state where the pre-registration sensor SS3 is in contact with the registration SB roller 213, thereby forming a paper loop in the conveyance path. At this time, the registration motor M3 is stationary in an excited state, and the ratchet solenoid SL5 of the clutch portion is turned on to fix and hold the registration SB roller.

  After the paper loop is formed, the pressure solenoid SL3 is turned off, the separation solenoid SL2 is turned on, and the pinch roller 233 facing the carry-in roller 212 is released from pressure contact, so that the paper PA is given a degree of freedom and faces the resist SB roller 213. The skew correction is performed with reference to the contact line of the pinch roller SB234, and the registration process is completed.

(Paper folding processing)
After the registration process, the process enters the paper folding process, but the process branches as follows based on the designated folding mode information.

[Third Folding Process in 1/3] Refer to FIG. 13 After the skew correction, the separation solenoid SL2 is turned OFF, the pinch roller 233 is pressed against the carry-in roller 212 again, and the registration motor M3 is driven forward to feed the paper PA. During this driving, the ratchet solenoid SL5 of the clutch portion is turned on to reliably transmit the drive. The registration motor M <b> 3 is pulse-counted by the pulse motor, and is driven and stopped until the sheet trailing edge passes through the sheet trailing edge stopper 242 in the downstream conveying path of the carry-in roller 212. The pulse amount corresponding to the trailing edge of the sheet passing through the sheet trailing edge stopper 242 is set according to the sheet size and folding mode, and the post-registration sensor SS4 performs pulse counting from the detection of the leading edge of the sheet.

  When the trailing edge of the sheet passes through the sheet trailing edge stopper 242, the registration motor M3 is driven in reverse while the ratchet solenoid SL5 remains on. The paper PA is reversely fed and the trailing edge hits the trailing edge stopper 242, and a paper loop is generated in the folding 1 loop forming unit 255. The sheet PA is nipped between the two folding rollers so as to follow the roller surfaces of the first roll 214 and the second roll 215.

  When the nip is conveyed by these two folding rolls, after a predetermined time when the sheet end is detected again by the post-registration sensor SS4, the ratchet solenoid SL5 and the registration motor M3 are turned off and the registration SB roller 213 is driven to rotate more than necessary. I try not to stress it. For the same purpose, the pinch roller SB 234 as the counterpart of the registration SB roller 213 may be separated instead of turning off the drive transmission.

  As described above, the paper PA is transferred to the first roll 214 and the second roll 215, and the two folding rolls are nip-conveyed and the first folding process is performed between the folding rolls. In the folded state, the paper PA is fed with the paper folded portion as the head, detected by the folded sheet detection sensor SS5, and provided on the second conveyance path 251 downstream thereof and the folding reference stopper 243 set to move to a predetermined position. To form a paper loop in the folded two-loop forming portion 256.

  In particular, in the 1/3 inner fold process, when a paper loop is generated in the fold 2 loop forming section 256, the first folded paper end face comes to the paper loop side. Entrainment ear breakage is likely to occur. For this reason, in the 1/3 inner folding process, the folding sheet detection sensor SS5 detects and after a predetermined time has elapsed, the pressing solenoid SL4 is turned on to operate the sheet pressing guide 244 to hold the first folded sheet end surface. , Preventing the ears from being bent due to entanglement due to floating of the end face. Similarly to the first folding process, the paper PA is nipped between the folding rollers so as to follow the roller surfaces of the second roll 215 and the third roll 216, the second folding process is performed, and the paper is folded and carried out. The fold is pressed by the roller 217 and the folding process is completed within 1/3.

[1 / 3Z folding process] See FIG.
The skew correction of the paper PA is performed in the same manner as the above-mentioned three-fold folding within 1/3, the pinch roller 233 is pressed against the carry-in roller 212 again, the registration motor M3 is driven to rotate forward, and the registration SB roller 213 drives the paper. Carries PA. At this time, the conveyance amount is pulse-counted, and the registration motor M3 is stopped at the time when (1-3-α) equivalent of the paper length L in the conveyance direction of the paper PA is sent.

  While the ratchet solenoid SL5 remains ON, the registration motor M3 stops in an excited state, the sheet PA is nipped by the registration SB roller 213, the pressure solenoid SL3 is turned ON to increase the conveyance force, and the conveyance roller 212 further increases the sheet PA. When the sheet is conveyed, a sheet loop is generated in the folding 1 loop forming unit 255. The paper loop becomes larger and the paper PA is nipped between the two folding rolls so as to follow the roller surfaces of the first roll 214 and the second roll 215, and the first folding process is performed. At this time, the registration SB roller 213 is driven and rotated in the same manner as the inner three-fold process so as not to apply unnecessary stress to the sheet, and the pressure solenoid SL3 is also turned off on the carry-in roller 212 side.

  After the first folding process, the paper PA is fed with the paper folded portion at the head in the folded state in the same manner as the one-third in-three folding process, and is applied to the folding reference stopper 243 set to move to a predetermined position. In contact with each other, a paper loop is generated in the folded two-loop forming unit 256. At this time, since the sheet end surface subjected to the first folding process is on the opposite side across the sheet loop and the sheet of the folding two-loop forming unit 256, there is a risk of the sheet end surface being involved, such as three-thirds inward folding process. Therefore, it is not necessary to press the sheet by operating the sheet pressing guide 244.

  Similarly to the first folding process, the paper PA is nipped between the folding rolls following the roller surfaces of the second roll 215 and the third roll 216, the second folding process is performed, and the carry-out roller is folded. The fold is pressed at 217 and the 1 / 3Z folding process is completed.

[1 / 4Z folding process] See FIG.
After the skew correction, the separation solenoid SL2 is turned off, the pinch roller 233 is again pressed against the carry-in roller 212, and the pressure solenoid SL3 is turned on to increase the carrying force of the carry-in roller 212 to carry the paper PA. The registration motor M3 is stationary in an excited state, the ratchet solenoid SL5 is ON, and the registration SB roller 213 is held and fixed. The sheet PA conveyed on the first conveyance path 250 by the carry-in roller 212 abuts on the resist SB roller 213 in a stationary state, and forms a sheet loop in the folded one loop forming unit 255. At this time, the pinch roller 233 to which the paper PA is transferred to the first roll 214 and the second roll 215 at the time when a predetermined time elapses from the re-pressing time point to the carry-in roller 212 so as not to apply unnecessary stress to the paper. The registration SB roller 213 is driven and rotated in the same manner as the inner three-folding process, and the pressure solenoid SL3 is also turned off on the carry-in roller 212 side.

  The paper loop becomes larger and the paper PA is nipped between the two folding rolls so as to follow the roller surfaces of the first roll 214 and the second roll 215, and the first folding process is performed. At this time, the conveyance path length to the nip point of the registration SB roller 213, the first roll 214, and the second roll 215 is equivalent to ¼ of the paper length L in the conveyance direction of the paper PA, and the paper length L of the paper PA. Can be folded at a portion corresponding to 1/4 of the above.

  At this time, the folding reference stopper 243 on the downstream second conveyance path 251 moves to a position corresponding to the 1 / 4Z folding process and comes into contact with the folded portion of the conveyed paper PA. Further, the paper PA nipped and conveyed between the two folding rolls forms a paper loop in the folding two-loop forming section 256, and the second folding 215 and the third roll 216 perform the second folding similarly to the first folding processing. Processing is performed. Further, the paper is folded and nipped by the carry-out roller 217, and the folded portion is pressurized, and the 1 / 4Z folding process is completed.

  The paper PA for which the folding process has been completed is transferred from the carry-out roller 217 to the conveyance roller 218 on the third conveyance path 252. A storage gate 241 is provided immediately after the transport roller 218, and selectively cuts the paper path after the paper folding process. When the 1 / 4Z folding process is selected, the storage gate 241 is not switched, and the sheet PA is transported on the third transport path 252 as it is and joined to the upper fourth transport path 253, and transported by the sheet discharge sensor SS8. Confirmed, the paper after the paper folding process is sent to the post-processing unit 300 together with the sheet discharge signal from the paper folding unit control unit 290, and the folding process is completed.

  In the case of the paper after the paper folding process excluding the 1 / 4Z folding process, the storage gate solenoid SL6 is turned ON, the storage gate 241 is switched to the folded sheet storage box side, the paper PA is confirmed by the folding portion discharge sensor SS6, and the folded sheet storage is performed. The folding process is completed by being stored in the box 280. The folded sheet storage box 280 has a full detection sensor SS7 and detects stack fullness.

1 is a cross-sectional view showing an embodiment of an image forming system according to the present invention. FIG. 5 is an explanatory diagram showing a paper folding procedure (paper folding mode) in the sheet processing apparatus, where (a) shows a 1/3 inner fold, (b) shows a 1 / 3Z fold, and (c) shows 1 / 4Z folding is shown. The whole block diagram of a paper folding unit. Explanatory drawing of the conveyance drive system of a paper folding unit. The block diagram which shows the mechanism of the press-contact separation of a carrying-in roller and a pinch roller. 4A and 4B are perspective views of a sheet presser guide, where FIG. 5A is an explanatory diagram showing a presser solenoid being in an ON state, and FIG. It is sectional drawing of a sheet | seat pressing guide, (a) shows at the time of insertion of a sheet | seat, (b) shows at the time of pressing of a sheet | seat. 4A and 4B are partial cross-sectional views of a sheet rear end stopper, in which FIG. 4A illustrates a state where the stopper is outside the conveyance path, and FIG. FIG. 6 is a diagram illustrating a relationship between a sheet rear end stopper and a carry-in roller. The block diagram of a fold reference | standard stopper. It is explanatory drawing of a resist SB roller drive transmission mechanism, (a) shows the state where the solenoid is OFF and the clutch is disengaged, (b) is the explanatory diagram of the state where the solenoid is ON and the clutch is engaged. Full detection mechanism for folded sheet storage box. Explanatory drawing which is an operation | movement flow of 1/3 inner folding, and shows a 1st folding form. Explanatory drawing which is an operation | movement flow of 1/3 inner folding, and shows a 1st folding form. Explanatory drawing which is an operation | movement flow of 1/3 inner folding, and shows a 1st folding form. Explanatory drawing which is an operation | movement flow of 1/3 inner folding, and shows a 1st folding form. Explanatory drawing which is an operation | movement flow of 1/3 inner folding, and shows a 2nd folding form. Explanatory drawing which is an operation | movement flow of 1/3 inner folding, and shows a 2nd folding form. Explanatory drawing which is an operation | movement flow of 1/3 folds inside, and shows the form of discharge to a storage box. Explanatory drawing which is an operation | movement flow of 1/3 folds inside, and shows the form of discharge to a storage box. Explanatory drawing which is a 1 / 3Z folding operation flow and shows a 1st folding form. Explanatory drawing which is a 1 / 3Z folding operation flow and shows a 1st folding form. Explanatory drawing which is a 1 / 3Z folding operation flow and shows a 1st folding form. Explanatory drawing which is a 1 / 3Z folding operation flow and shows a 1st folding form. Explanatory drawing which shows the operation | movement flow of 1 / 3Z folding, and shows a 2nd folding form. Explanatory drawing which shows the operation | movement flow of 1 / 3Z folding, and shows a 2nd folding form. Explanatory drawing which is an operation | movement flow of 1 / 3Z folding, and shows the form of discharge to a storage box. Explanatory drawing which is an operation | movement flow of 1 / 3Z folding, and shows the form of discharge to a storage box. Explanatory drawing which is a 1 / 4Z folding operation | movement flow and shows a 1st folding form. Explanatory drawing which is a 1 / 4Z folding operation | movement flow and shows a 1st folding form. Explanatory drawing which is a 1 / 4Z folding operation | movement flow and shows a 1st folding form. Explanatory drawing which is a 1 / 4Z folding operation | movement flow and shows a 1st folding form. Explanatory drawing which shows the operation | movement flow of 1 / 4Z folding and shows a 2nd folding form. Explanatory drawing which shows the operation | movement flow of 1 / 4Z folding and shows a 2nd folding form. Explanatory drawing which is a 1 / 4Z folding operation | movement flow and shows the form of discharge to a post-processing unit. Explanatory drawing which is a 1 / 4Z folding operation | movement flow and shows the form of discharge to a post-processing unit. Explanatory drawing which is a 1 / 4Z folding operation | movement flow and shows the form of discharge to a post-processing unit. Explanatory drawing which is a 1 / 4Z folding operation | movement flow and shows the form of discharge to a post-processing unit.

Explanation of symbols

100 Image forming unit 200 Paper folding unit 213 Registration SB roller (tip regulating means)
214 First roll 215 Second roll 216 Third roll 230 Pinch roller unit 242 Sheet rear end stopper (rear end regulating means)
243 Folding reference stopper (butt stopper member)
244 Sheet holding guide 250 First conveyance path (sheet conveyance path)
251 Second transport path (folded sheet transport path)
252 Third conveyance path (sheet carry-out path)
253 Fourth transport pass 300 Post-processing unit

Claims (8)

First folding roll means disposed in the sheet conveyance path;
A folded sheet conveying path that branches out from the sheet conveying path and carries out the folded sheet from the folding roll means;
A second folding roll means disposed in the folded sheet conveying path,
The sheet processing apparatus according to claim 1, wherein a sheet pressing unit that presses the folded sheet toward the folding side is provided in the folded sheet conveyance path. First and second conveying means disposed at a distance in the sheet conveying path;
A first folding roll means disposed between the first and second conveying means;
A folded sheet conveying path that branches off from the conveying path and carries out the folded sheet from the first folding roll means;
Stopper means disposed in the folded sheet conveyance path for restricting the leading end of the sheet from the first folding roll means,
Second folding roll means disposed in the folded sheet conveying path so as to fold the rear end side of the sheet whose front end is regulated by the stopper means onto the folded piece on the sheet leading end side;
A sheet processing apparatus comprising: a sheet pressing unit that presses the folded piece on the leading end side of the sheet guided to the second folding roll unit in the overlapping direction. The sheet pressing means is configured to be movable between a position retracted from the folded sheet transport path and an operating position for pressing the sheet end in the overlapping direction in the folded sheet transport path.
The sheet processing apparatus according to claim 1, wherein the sheet pressing unit includes a driving unit that moves between a retracted position and an operating position.   The sheet processing apparatus according to claim 3, wherein the driving unit moves the sheet pressing unit from the retracted position to an operating position in accordance with a sheet length and / or a sheet folding procedure. The first and second folding roll means are composed of three rollers that are pressed against each other,
Forming a first folding roll means for folding and unloading the sheet from the conveyance path with a first roll and a second roll that are pressed against each other;
5. The sheet processing according to claim 1, wherein second sheet folding means for folding and unloading the sheet from the folded sheet conveyance path is formed by the first roll and the third roll. apparatus.   6. The sheet processing according to claim 1, wherein the folded sheet conveyance path includes a curved portion that biases a sheet folded by the first folding roll unit in a folding direction. apparatus. An image forming unit for forming an image on a sheet;
A paper folding unit for folding the sheet from the sheet discharge port of the image forming unit;
A post-processing unit that performs post-processing such as stapling and punching on the sheet from the discharge port of the paper folding unit,
The paper folding unit is
A conveyance path for conveying a sheet from the image forming unit;
First and second conveying means disposed at a distance in the sheet conveying path;
A first folding roll means disposed between the first and second conveying means;
A folded sheet conveying path that branches off from the conveying path and carries out the folded sheet from the first folding roll means;
Stopper means disposed in the folded sheet conveyance path for restricting the leading end of the sheet from the first folding roll means,
A second folding roll means disposed in the folded sheet conveying path so as to fold the rear end side of the sheet whose front end is regulated by the stopper means on the folded piece on the sheet leading end side;
Sheet pressing means for pressing the folded piece on the leading end side of the sheet guided to the second folding roll means in the overlapping direction;
An image forming apparatus comprising: The paper folding unit includes a stacker that stores folded sheets in the folded sheet conveyance path via path switching means;
The image forming apparatus according to claim 7, further comprising a sheet discharge path that conveys the folded sheet to the post-processing unit.

Images