Sheet folding and image formation apparatus

In a sheet folding apparatus, to enable a jammed sheet to be removed with ease when a jam occurs, a casing having a carry-in entrance and a carrying-out exit is divided into an upper unit and a lower unit via a first transport path for carrying a sheet from the carry-in entrance to the carrying-out exit, a second transport path for performing folding processing on a sheet is disposed in the direction for crossing the first transport path, and in the upper unit are disposed a sheet front end switchback path for reversing and carrying the sheet toward a folding roller pair and sheet deflecting means for guiding the sheet to the folding roller pair. Then, the upper unit is coupled to the lower unit to be openable and closable by a hinge shaft rotating around one side end portion orthogonal to the sheet transport direction of the first transport path.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a sheet folding apparatus for folding a sheet fed from an image formation apparatus to feed to a post-processing apparatus, and more particularly, to improvements in the jam handling mechanism to remove a sheet jam.

2. Description of the Related Art

Generally, this type of sheet folding apparatus has been known as an apparatus for folding a sheet with an image formed thereon by an image formation apparatus such as a printing press, printer apparatus and copier in a predetermined fold position to perform finish processing.

For example, Japanese Patent Application Publication No. 2009-018494 proposes an apparatus in which a sheet folding apparatus is coupled to a sheet discharge outlet of an image formation apparatus, folds a sheet with an image formed for filing, and carries the sheet out to a subsequent binding processing apparatus (post-processing apparatus). In the document, the sheet folding apparatus is coupled to the sheet discharge outlet of the image formation apparatus, and a bookbinding processing apparatus is disposed on the downstream side of the sheet folding apparatus.

Not only such a system configuration in Japanese Patent Application Publication No. 2009-018494, it is known widely that part of an apparatus casing is configured to be openable and closable to open and close the path when a paper jam occurs in the transport path of sheets in the sheet folding apparatus. Such a structure is generally configured by hinge-coupling part of a casing to an apparatus frame to be openable and closable and exposing the sheet transport path to the outside with the casing opened.

Japanese Patent Application Publication No. S61-002637 discloses a post-processing apparatus and proposes a jam open/close mechanism for hinge-coupling one side end edge (for example, the apparatus left side end portion) orthogonal to the sheet transport direction in an apparatus for collating and collecting sheets fed from an image formation apparatus to perform binding processing.

More specifically, first, such a sheet folding apparatus as described above is known in Japanese Patent Application Publication No. 2009-018494, etc. The sheet folding apparatus is disposed between the image formation apparatus and the post-processing apparatus, and folds an image-formed sheet to feed to the post-processing apparatus. The sheet folding apparatus is provided with a transport path for carrying a sheet from a carry-in entrance to a carrying-out exit without performing folding processing on the sheet, and a folding processing path for performing the folding processing on a sheet to feed to the carrying-out exit.

Then, in the sheet folding apparatus disposed between the image formation apparatus and the prost-processing apparatus, an apparatus configuration is required which is small and compact as possible, and particularly, slim in the sheet feed direction. It is natural because the installation space of the entire system is reduced (narrowed).

Therefore, previously, the applicant of the invention conceived slimming the folding processing mechanism by placing a folding processing path for performing folding processing on a sheet fed from the carry-in entrance in the direction for crossing a transport path (through-pass path) for carrying a sheet from the carry-in entrance to the carrying-out exit without performing the folding processing, and filed the patent application (Japanese Patent Application No. 2009-291375). When a sheet jam occurs in such an apparatus configuration, the need arises for opening the transport path to remove the jam.

The inventor of the invention arrived at the idea that it is possible to retrieve jam sheets occurring in both paths, by dividing the configuration into two upper and lower portions with the through-pass path as a boundary and opening and closing the upper unit in the path configuration in which the folding processing path is disposed in the direction for crossing the through-pass path. Concurrently therewith, the inventor arrived at the idea that it is possible to reduce the size of the entire system without the image formation apparatus and the post-processing apparatus located at the front and back and the open/close space interfering with one another, by providing the upper unit with open/close motion around the hinge in the side end portion (apparatus rear side end portion) parallel with the sheet transport direction with respect to the lower unit.

Further, second, in Japanese Patent Application Publication No. S61-002637, when a sheet is jammed in a press-contact portion in a pair of folding rollers, the sheet transport mechanism is opened, and the sheet is pulled out with the sheet nipped between the rollers. Therefore, in a thin sheet or a sheet becoming wrinkled by the jam, part of the sheet may be broken and remain inside the apparatus. Alternately, in pulling out the sheet nipped between the rollers inside the apparatus, the operator may be injured.

Then, the inventor of the invention arrived at the idea that it is possible to release a plurality of press-contact portions by withdrawing a roller positioned in the center, and at the same time, restore to the original engagement relationship reliably in a folding roller mechanism in which a plurality of press-contact rollers is disposed around the roller positioned in the center.

OBJECT OF THE INVENTION

It is a principal object of the invention to provide a sheet folding apparatus that permits a jammed sheet to be removed with ease when the jam occurs in the sheet folding apparatus which is disposed between an image formation apparatus and a post-processing apparatus to perform folding processing on an image-formed sheet.

In other words, first, it is an object of the invention to provide a sheet folding apparatus which permits a jammed sheet to be removed with ease in a transport path for carrying a sheet to a folding processing position, without the open/close space to open and close part of the casing for the removal interfering with the apparatuses disposed on the upstream side and the downstream side, and which enables the apparatus to be made small and compact.

Further, second, it is another object to provide the sheet folding apparatus which enables a sheet jammed in a lower portion of the sheet folding apparatus for performing folding processing on a sheet to be reliably removed by simplified operation.

BRIEF SUMMARY OF THE INVENTION

To attain the aforementioned objects, in the invention, a casing having a carry-in entrance and a carrying-out exit is divided into an upper unit and a lower unit via a first transport path for carrying a sheet from the carry-in entrance to the carrying-out exit, a second transport path for performing folding processing on a sheet is disposed in the direction for crossing the first transport path, and in the upper unit are disposed a sheet front end switchback path for reversing and carrying the sheet toward a folding roller pair and sheet deflecting means for guiding the sheet to the folding roller pair. Then, the upper unit is coupled to the lower unit to be openable and closable by a hinge shaft rotating around one side end portion orthogonal to the sheet transport direction of the first transport path.

The upper unit is coupled to the lower unit to be openable and closable, in the upper unit are disposed an upper sheet guide of the first transport path and the sheet front end switchback path constituting part of the second transport path, and therefore, by opening the upper unit, it is possible to retrieve a jam sheet in each of the first and second transport paths. Accordingly, it is possible to retrieve a jam sheet arising in the path by simplified structure.

Further, the upper unit is coupled to the lower unit to rotate by the hinge shaft around one side end portion orthogonal to the sheet transport direction of the first transport path for guiding a sheet from the carry-in entrance to the carrying-out exit, and therefore, without the image formation apparatus and the post-processing apparatus respectively positioned on the upstream side and the downstream side in the sheet transport direction and open/close area of the upper unit interfering (overlapping) with one another, it is possible to reduce the size of the installation space of the entire system.

Furthermore, to attain the above-mentioned objects, in the invention, a plurality of rolls is brought into press-contact with a first roll positioned in the center in the order of the second, third and fourth rolls, and a guide member is provided which guides a folded sheet along the periphery of the first roll in between the third roll and the fourth roll.

Then, the first roll is provided in a first bracket member that swings in the direction separating from the second and third rolls, and the fourth roll and the guide member are provided in a second bracket member that swings in the direction separating from the first roll. Then, the first bracket member and the second bracket member are interlocked to swing in the separation direction by operating means provided in one of the members.

By separating the first roll positioned in the center from the second and third rolls, it is possible to concurrently release press-contact in the first folding press-contact portion and the second folding press-contact portion, and it is thereby possible to remove a jam sheet by simplified structure and operation. Concurrently therewith, it is possible to withdraw the fourth roll in press-contact with the first roll and the guide member at the same time in the separation direction. Accordingly, it is possible to withdraw the folding enhancement press-contact portion and the guide member therefor in conjunction with each other concurrently with the folding press-contact portions, and therefore, the jam handling is extremely simplified.

Further, the structure for the handling is that the first roll, and the fourth roll and guide member are respectively attached to the first bracket member and the second bracket member to be swingable in the separation direction, and that the first bracket member and the second bracket member are interlocked to swing in the separation direction by the operating means provided in one of the members, and it is thereby possible to release a plurality of press-contact portions by simplified structure and simplified operation.

By this means, in the sheet folding apparatus, when a jam occurs, it is possible to remove a jammed sheet with ease.

DETAILED DESCRIPTION OF THE INVENTION

The invention will specifically be described below based on Embodiments shown in the figures.FIG. 1shows an image formation system provided with a sheet folding apparatus B according to the invention. This system is comprised of an image formation apparatus A and a post-processing apparatus C, and the post-processing apparatus C is installed with the sheet folding apparatus B as a unit.

The image formation apparatus A is configured as a printer, copier, printing press or the like for sequentially forming images on sheets. The apparatus as shown inFIG. 1is comprised of an image formation section7, original document reading section20and feeder section (original document feeding apparatus)25as a complex copying machine having the copier function and the printer function.

Further, the post-processing apparatus C is configured to perform post-processing such as folding processing, punching processing, sealing processing and binding processing on a sheet with an image formed in the image formation apparatus A. Then, the post-processing apparatus C is integrally provided with the sheet folding apparatus B for performing folding processing on a sheet with an image formed. The sheet folding apparatus B, image formation apparatus A and post-processing apparatus C will be described below in this order.

The sheet folding apparatus B according to the invention is incorporated into the image formation apparatus A or the post-processing apparatus C, or is configured as an apparatus (stand-alone configuration) independent of the apparatuses. The apparatus as shown in the figure is disposed between the image formation apparatus A and the post-processing apparatus C as an optional unit.

In the sheet folding apparatus B, as shown inFIG. 3illustrating the entire configuration, a casing29is provided with a carry-in entrance30and a carrying-out exit31, the carry-in entrance30is arranged in a position continued to a main-body sheet discharge outlet18of the image formation apparatus A on the upstream side, and the carrying-out exit31is arranged in a position continued to a sheet receiving opening69of the post-processing apparatus C on the downstream side. In addition, in the invention, there are cases that the sheet folding apparatus B is not provided with an independent casing29, and for example, is incorporated into a casing of the post-processing apparatus C, and the cases do not require the carry-in entrance30and carrying-out exit31.

Accordingly, in the following description, the carry-in entrance30is synonymous with a carry-in portion, the carrying-out exit31is synonymous with a carrying-out portion, and for convenience in description, the description is given while assuming that the carry-in portion is the carry-in entrance30and that the carrying-out portion is the carrying-out exit31.

As shown inFIG. 3, the carry-in entrance30and carrying-out exit31are disposed opposite each other across the casing29. The carry-in entrance30and carrying-out exit31shown in the figure are disposed in opposite positions in the substantially horizontal direction. Then, in between the carry-in entrance30and the carrying-out exit31are disposed a first transport path32(sheet transport path; the same in the following description) for carrying out a sheet from the carry-in entrance30to the carrying-out exit31without performing folding processing, and a second transport path33(folding processing path; the same in the following description) for performing the folding processing on a sheet from the carry-in entrance30to carry out to the carrying-out exit31. A “sheet transport mechanism” for carrying a sheet in the predetermined direction (horizontal direction) is disposed in the first transport path32, and a “folding processing mechanism” for performing the folding processing on a sheet is disposed in the second transport path33.

In the apparatus ofFIG. 3, the casing29is comprised of an upper unit29A and a lower unit29B that are divided vertically via the first transport path32for guiding a sheet from the carry-in entrance30to the carrying-out exit31without performing folding processing.

Then, as shown inFIG. 3, in the upper unit29A are disposed an upper sheet guide32aconstituting the first transport path32, and a sheet front end switchback path34(first switchback path; the same in the following description) constituting the second transport path33. Concurrently therewith, the upper unit29A is provided with a carry-in roller40a, gate stopper43, pinch roller42, and carrying-out roller62a. The carry-in roller40aand carrying-out roller62aare supported by rotary shafts of the direction orthogonal to the sheet transport direction (the arrow direction inFIG. 2) of the first transport path32.

The gate stopper43is configured to be swingable on a spindle43xof the direction orthogonal to the sheet transport direction, as described later, and similarly, the pinch roller42is configured to be swingable on a spindle42xof the direction orthogonal to the sheet transport direction.

Meanwhile, in the lower unit29B are disposed a lower sheet guide32bconstituting the first transport path32, folding roller pair (41,49,50), sheet discharge paths36,37, storage stacker65, and sheet discharge roller67.

In addition, a first folding deflecting means53is provided in the lower unit29B (seeFIG. 5). Then, in the lower unit29B are disposed a shift motor MS for moving the first and second folding deflecting means53,54up and down, and a feeding motor Mf.

In such a unit configuration, the upper unit29A is coupled to the lower unit29B to be openable and closable by the hinge shaft28around one side end portion orthogonal to the sheet transport direction of the first transport path32.FIG. 4shows a closed state, andFIG. 5shows an open state. In this closed state, as shown inFIG. 3, the upper sheet guide32aand lower sheet guide32bare opposed to each other with a predetermined spacing and form the first transport path32. Meanwhile, in the open state, the upper sheet guide32areleases the path in the state ofFIG. 5at a predetermined angle of θ around the hinge shaft28with respect to the lower sheet guide32b.

FIGS. 6A and 6Bshow a mechanism for guiding the open/close operation of the unit in operating the upper unit29A to be opened and closed around the hinge shaft28with respect to the lower unit29B. As shown inFIG. 6A, the upper unit29A is opened and closed around the hinge shaft28with respect to the lower unit29B. At this point, one of the upper unit29A and lower unit29B is provided with guide pins27p, while the other one is provided with guide grooves27g. Then, when open/close motion is performed around the hinge shaft28, the guide pin27pis guided along the guide groove27g, and both of the units undergo the open/close motion in the correct position without rattling. In addition, in performing the open/close motion, it is necessary that the gate stopper mechanism and the driving system of the pinch roller mechanism are engaged and released, and the configuration will be described later.

Thus, the upper unit29A is coupled to the lower unit29B to be openable and closable, in the upper unit29A are disposed the upper sheet guide32aof the first transport path32and the first switchback path34, and therefore, by opening the upper unit29A, it is possible to retrieve a jam sheet in each of the first and second transport paths32,33. Accordingly, it is possible to retrieve a jam sheet arising in the path by simplified structure.

Further, the upper unit29A is coupled to the lower unit29B to rotate by the hinge shaft28around one side end portion orthogonal to the sheet transport direction of the first transport path32, and therefore, without the image formation apparatus A and the post-processing apparatus C respectively positioned on the upstream side and the downstream side in the sheet transport direction and open/close area of the upper unit29A interfering (overlapping) with one another, it is possible to reduce the size of the installation space of the entire system.

As shown inFIG. 3, in the casing29, the first transport path32is disposed between the carry-in entrance30and the carrying-out exit31. This path may be a linear path disposed in the horizontal direction as shown in the figure, may be configured as a curved path, or may be disposed in the vertical direction, and it is possible to adopt any configuration. As described above, the first transport path32guides a sheet from the carry-in entrance30to the carrying-out exit31without performing the folding processing.

Further, the second transport path33is configured as a path for performing the folding processing on a sheet from the carry-in entrance30. Therefore, the second transport path33branches off from the first transport path32, and is configured to guide a sheet from the carry-in entrance30to sheet folding positions Np1and Np2. Concurrently therewith, as shown inFIG. 3, the second transport path33is disposed in a direction in which the path33crosses the first transport path32, and the first folding position Np1and the second folding position Np2are set in this path.

Then, the second transport path33is comprised of the first switchback path (first reverse path)34for guiding the sheet front end for first folding to the first folding position Np1, and a second switchback path (second reverse path)35for guiding the folded sheet front end to the second folding position Np2to perform second folding on the folding-processed sheet.

Thus, the second transport path33is disposed in the direction to cross the first transport path32, where the first switchback path34is disposed in the area above the first transport path32, the second switchback path35for carrying a sheet from the cross portion to the downstream side (the direction of the second folding position Np2) is disposed in the area below the first transport path32, and the paths34and35are thus configured to be opposed vertically.

Then, each of the first switchback path34and second switchback path35is comprised of a curved path and formed substantially in the shape of an S-curve as shown inFIG. 3. In the second transport path (folding processing path)33, a folding processing section48described later is disposed in the first folding position Np1and second folding position Np2, and the path33is connected to a sheet discharge path36for carrying out the folded sheet from the second folding position Np2toward the carrying-out exit31.

In addition, the first transport path32and the second transport path33are disposed to cross each other, and the first switchback path34for guiding the sheet to the first folding position Np1may be disposed below the first transport path32, while the second switchback path35for guiding the folding-processed sheet to the downstream side may be disposed above the first transport path32.

Further, in the Embodiment ofFIG. 3, the first transport path32is disposed in the horizontal direction, and when the first transport path32is disposed in the vertical direction in the casing29, it is possible to arrange the first switchback path34and second switchback path35to the left and right areas of the first transport path32to be opposite each other.

Further, in the Embodiment as shown inFIG. 3, in relation to the second switchback path35guiding the folded sheet to the second folding position Np2to perform second folding on the sheet, the path35is configured to reverse the feeding direction of the sheet, but when second folding is not performed on the sheet, the path35can be a path to extend straight, and in this case, the need is eliminated for providing the second switchback path as descried previously.

The second transport path33is connected to the sheet discharge path36for guiding the folding-processed sheet to the carrying-out exit31. The sheet discharge path36shown in the figure is provided in between the second folding position Np2for performing second folding on the sheet and the carrying-out exit31. In the sheet discharge path36is disposed a sheet discharge path37for guiding the folded sheet to a storage stacker65from a sheet discharge outlet51different from the carrying-out exit31.

Then, a path length (L1) of the first switchback path34for guiding a sheet from the first transport path32to the first folding position (first nip portion) Np1and a path length (L2) of the second switchback path35for guiding the folded sheet subjected to first folding to the second folding position (second nip portion) Np2are configured so that path length L1>path length L2.

A path length L3of the sheet discharge path37for guiding the sheet further subjected to the folding processing to the storage stacker65from the second folding position Np2is configured so that L3<L2<L1. This is because when the first folding position (first nip portion) Np1is disposed near the first transport path32, the path lengths are L3<L2<L1as a result, and the path configuration is thereby made compact.

Accordingly, the first switchback path34with the long path length is disposed in the upper area of the first transport path32, the second switchback path35and the sheet discharge path37with the short path lengths are disposed in the lower area opposite the upper area, and further, the storage stacker65is disposed below the second switchback path35and the sheet discharge path37. By such a layout configuration, it is possible to make the inside space of the casing29compact.

The following path switching means63is disposed in the cross portion of the above-mentioned first transport path32and second transport path (folding processing path)33. As described previously, the second transport path33branches off from the first transport path32and guides a sheet fed from the carry-in entrance30to the first and second folding positions Np1, Np2. Therefore, the path switching means63is disposed in the cross portion of the first and second transport paths32and33. As shown inFIG. 3, a base end portion is axially supported by an apparatus frame (in the figure, spindle62xof the carrying-out roller62a) outside the path to be swingable.

Then, the path switching means63guides a sheet fed to the first transport path32to the first switchback path34of the second transport path33in the solid-line attitude in FIG.3, while guiding a sheet fed to the first transport path32to the carrying-out exit31from the carrying-roller pair62in the dashed-line attitude inFIG. 3.

A sheet guide61is provided in the cross portion of the first transport path32and second transport path33together with the path switching means63. The sheet guide61is disposed in between the second roller41and the carrying-out roller pair62in the first transport path32, guides a sheet fed from the carry-in roller pair40to the second transport path33, and concurrently therewith, guides a reversed sheet from the first switchback path34to the first folding position Np1. Further, the sheet guide61guides a sheet fed to the first transport path32to the carrying-out exit31from the carrying-out roller pair62without guiding the sheet to the second transport path33.

Therefore, the sheet guide61is disposed in the cross portion with a relatively long transport span, and guides the sheet to the second transport path33side or carrying-out exit31side in cooperation with the path switching means63as described previously. In the apparatus as shown in the figure, as shown inFIG. 3, the guide61comprised of a guide plate supported swingably in the spindle61xby the apparatus frame.

As shown inFIG. 14, a link lever60is axially supported swingably by the path switching means63, and the link lever and path switching means63are integrally combined. Then, an electromagnetic solenoid60L is coupled to a front end portion of the link lever60, and a return spring60sis extended in the direction in which the path switching means63guides a sheet to the second transport path33side.

Accordingly, when the electromagnetic solenoid60L is ON, the path switching means63is positioned in the first attitude (attitude for guiding a sheet to the second transport path33). Further, when the electromagnetic solenoid60L is turned OFF, the link lever60rotates in a counterclockwise direction shown in the figure on the spindle62xas the center by action of the return spring60s, and positions the path switching means63in the second attitude (attitude for guiding a sheet to the carrying-out exit31).

Further, the path switching means63is disposed in the upper unit29A to be swingable between the first guide attitude facing the first transport path32and the second attitude shifted outside the path. The path switching shift means for swinging the path switching means63between the first guide attitude and the second guide attitude is comprised of a swing member (actuation lever)63yintegrally provided in the swing spindle, and the lever member60that engages in the swing member. Then, the lever member60has an engagement surface that engages in the swing member, and a guide surface60zfor guiding the engagement surface to the swing member63ywhen the upper unit A rotates around the hinge shaft28.

In the second transport path33are disposed the second roller41, first roller49and third roller50to come into press-contact with one another. The first nip portion (first folding position) Np1for first folding the sheet is formed in a press-contact point between the second roller41and first roller49, and the second nip portion (second folding position) Np2for second folding the sheet is formed in a press-contact point between the first roller49and the third roller50.

Meanwhile, in the roller diameter of each of the first, second and third rollers, the first roller diameter is the maximum, and for example, 30 mm, the second and third roller diameters are 20 mm, and the first roller49positioned in the center is configured to have the maximum diameter (for example, 1.5 time). This is because of configuring the folding portion front end to be compact by arranging the second roller41and third roller50around the periphery of the first roller49in the shape of satellites. In other words, with respect to the first roller49with the large diameter, the second roller41with the small diameter is brought into press-contact on the upstream side, the third roller50with the small diameter is brought into press-contact on the downstream side, and thereby, the first nip portion Np1for first folding and the second nip portion Np2for second folding are formed.

Further, the second roller41is disposed in the position such that part of the periphery faces the first transport path32, and the pinch roller42is brought into press-contact with the periphery of the roller41. By this means, the sheet in the first transport path32is fed to the downstream side by the second roller41and pinch roller42, and it is not necessary to provide the first transport path32with specific transport means and driving mechanism thereof.

[Configuration of the Folding Deflecting Means]

In the folding roller means comprised of three rollers (41,49,50) as described above, the first folding deflecting means53is disposed in the first nip portion Np1, and the second folding deflecting means54is disposed in the second nip portion Np2. The first folding deflecting means53and the second folding deflecting means54are formed of a mechanism that fold positions of the sheet fed to the second transport path33are inserted in the first nip portion Np1and the second nip portion Np2.

In the apparatus as shown in the figure, the first folding deflecting means53and the second folding deflecting means54are provided with the function of “inserting the fold position of the sheet in a roller nip portion” and the function of “feeding the front end and rear end of the sheet to the nip portion”. Therefore, the first and second folding deflecting means53,54are respectively provided with driven rollers53a,54aand curved guides53b,54band are configured to shift to positions from a withdrawal position outside the path to an actuation position inside the path. Then, by the operation of the driven roller and curved guide shifting from the withdrawal position to the actuation position, the fold position of the sheet is inserted in the nip portion, and then, the driven roller comes into press-contact with the periphery of the folding roller to rotate by being driven, and thereby acts to feed the front and rear ends of the sheet to the nip portion.

[Configuration of the First Folding Deflecting Means]

As shown inFIG. 7, to guide the fold of the sheet to the first nip portion (press-contact point) Np1, the first folding deflecting means53is comprised of the driven roller53a, curved guide53band up-and-down member53c.

As shown inFIG. 7, the first nip portion Np1for first folding the sheet is comprised of the second roller41and first roller49, the second roller41is disposed on the upstream side, and the first roller49is disposed on the downstream side. Thus, the driven roller53ais disposed in a position for coming into contact with the periphery of the first roller49. Then, the curved guide53bis configured to be a curved surface along the periphery of the second roller41positioned on the upstream side.

The driven roller53aand the curved guide53bare supported by the up-and-down member53c. The up-and-down member53cis comprised of a bracket member (frame member) of an appropriate shape, the driven roller53cis supported rotatably by the up-and-down member53c, and concurrently, the curved guide53bis fixed to the member53c. Then, the up-and-down member53cis supported by a guide rail (not shown) provided in the apparatus frame, and is configured to move up and down between an actuation position (dashed-line position inFIG. 7) in which the driven roller53acomes into contact with the periphery of the first roller49, and a waiting position (solid-line position inFIG. 7) in which the driven roller53aretracts out of the second transport path33. The up-and-down member53cis coupled to a shift motor MS described later, and shifts positions of the driven roller53aand curved guide53bbetween the actuation position and the waiting position.

The above-mentioned driven roller53acomes into press-contact with the first roller49positioned on the downstream side, and the press-contact point is shown by p2inFIG. 7. Then, when the fold position of the sheet is guided to the first nip portion Np1, the rear end side of the sheet is provided with the transport force in the press-contact point p1, and is guided to the first nip portion Np1along the periphery of the second roller41. Further, the front end side of the sheet is provided with the transport force in the press-contact point p2, and is guided to the first nip portion Np1along the periphery of the first roller49.

At this point, the transport length Lx between the press-contact point p1and the first nip portion Np1and the transport length Ly between the press-contact point p2and the first nip portion Np1are set at Lx>Ly. The position of the driven roller53ais set in such a transport length relationship. Then, the curved guide53bforms the curved guide surface in the shape of a curve along the periphery of the second roller41with the longer transport length.

In other words, conventionally, the blade member for guiding a fold of the sheet to the nip portion (Np1, Np2) has been provided separately from the sheet feeding means, and has become a cause of displacement of the fold or wrinkle occurring in the sheet when timing for acting on the sheet deviates. To solve the problem, in the apparatus as shown in the figure, the transport length Lx of the second roller41on the upstream side of the sheet fed to the first nip portion Np1and the transport length Ly of the first roller49on the downstream side are set at [Lx>Ly], concurrently the curved guide surface of the curved guide53bis configured in the shape for bringing the sheet along the periphery of the second roller41with the longer transport length, and the driven roller53aand the curved guide53bare concurrently shifted from the waiting position to the actuation position.

By thus configuring, it is possible to guide the fold of the sheet correctly to the first nip portion Np1without using particular folding blade means.

[Configuration of the Second Folding Deflecting Means]

The second folding deflecting means54will be described next. As shown inFIG. 7, the second folding deflecting means54is comprised of an up-and-down member54c, driven roller54aattached to the member54c, and curved guide54b. The driven roller54ais disposed in a position opposite the periphery of the third roller50positioned on the downstream side of the first roller49, and the curved guide54bis disposed in a position opposite the periphery of the first roller49positioned on the upstream side.

Concurrently therewith, the driven roller54aand the curved guide54bare configured to shift to positions between a withdrawal position Wp withdrawn from the carrying path (hereinafter, referred to as a sheet path Sp; seeFIG. 7) of the sheet and an actuation position Ap entering inside the sheet path Sp by the up-and-down member54c.

The up-and-down member54cis provided with a sleeve54s, and a support stem of the driven roller54ais fitted with the sleeve54sslidably. Thus, the driven roller54ais fitted and supported by the up-and-down member54creciprocating in the predetermined stoke S, and shifts to positions between the withdrawal position Wp and the actuation position Ap by the up-and-down member54cshifting.

Then, an adjuster spring54eis provided between the driven roller54afitted with the sleeve54sand the up-and-down member54c, and the driven roller54ais biased in the direction of the third roller50by the adjuster spring54e. Concurrently therewith, an engagement protrusion54kis integrally provided in the up-and-down member54c. The engagement protrusion54kengages in a flange portion54nof the support stem.

Meanwhile, the curved guide54bis swingably supported by the apparatus frame. The guide as shown in the figure is integrally formed in a bracket54dfreely fitted with a rotary shaft41xof the second roller41, and the guide surface of the curved guide54bis disposed in a position opposite the periphery of the first roller49. Then, the curved guide54bis engaged to shift to positions between the withdrawal position Wp withdrawn from the sheet path Sp and the actuation position Ap entering inside the path in conjunction with reciprocating motion of the up-and-down member54c.

Therefore, the bracket54dis provided with a biasing spring54hfor biasing toward the withdrawal position Wp and an engagement piece54j. The engagement piece54jengages with the up-and-down member54c, and is configured to shift from the withdrawal position Wp to the actuation position Ap in conjunction with the shift of the up-and-down member54c(against the biasing spring54h).

In the above-mentioned configuration, the up-and-down member54cand the shift motor MS constitute the shift means for shifting the driven roller54aand curved guide54bto positions between the withdrawal position Wp and the actuation position Ap. Further, as a substitute for the configuration of the up-and-down member54creciprocating in a predetermined stroke, it is naturally possible to constitute the shift means using an actuator such as an actuation solenoid. In this case, the driven roller54aand the curved guide54bare coupled to a single actuation solenoid, or individual actuation solenoids.

The sheet transport mechanism of the first transport path32ad second transport path33will be described according toFIG. 3. In the first transport path32, the carry-in roller pair40is disposed in the carry-in exit (carry-in portion)30, the carrying-out roller pair62is disposed in the carrying-out exit (carrying-out portion)31, and a register roller is disposed between the rollers. The register roller shown in the figure is comprised of the periphery of the second roller41described later and the pinch roller42in press-contact with the roller41.

Accordingly, in the first transport path32are disposed the carry-in roller pair40, carrying-out roller pair62and register roller (second roller)41.

Then, the carry-in roller pair40is comprised of a pair of rollers40a,40b, and one of the rollers,40b, is coupled to the feeding motor Mf described later. Similarly, the carrying-out roller pair62is comprised of a pair of rollers62a,62b, and one of the rollers,62b, is coupled to the feeding motor Mf. Further, the pinch roller42is disposed to, rotate in accordance with the second roller41, and the second roller41is also coupled to the feeding motor Mf.

In the second transport path (folding processing path)33are disposed the second roller41, first roller49and third roller50coming into press-contact with one another, and the sheet discharge roller pair67is disposed in the sheet discharge path37. Then, as shown inFIG. 3, the second transport path33(first switchback path34and second switchback path35) is not provided with any sheet transport mechanism.

Then, to the second transport path33, the sheet is carried in the first switchback path34by the carry-in roller pair40and the register roller (second roller)41disposed in the first transport path32, and is fed to the downstream side by the first and second rollers49,41.

The apparatus shown in the figure is characterized by simplifying the sheet transport mechanism disposed in the first and second transport paths32,33and thereby reducing the size, noise and power consumption of the apparatus. Therefore, in the first transport path32, part of the periphery of the folding roller (second roller41) disposed in the second transport path33is arranged to face the first transport path32in between the carry-in roller pair40and the carrying-out roller pair62.

Then, the pinch roller42is disposed around the periphery of the second roller41to carry the sheet fed from the carry-in roller pair40to the first switchback path34. By this means, it is not necessary to provide a specific transport roller in the first transport path32, and it is possible to achieve simplification of the transport mechanism.

Concurrently therewith, the second roller41is rotated in performing the folding processing on the sheet in a mode for carrying the sheet from the carry-in roller pair40to the first switchback path34by the carry-in roller pair40and the second roller41, while being halted so that the sheet is fed from the carry-in entrance30to the carrying-out exit31by the carry-in roller pair40and the carrying-out roller pair62in a mode for carrying a sheet from the carry-in entrance30to the carrying-out exit31without performing the folding processing on the sheet. By this means, it is possible to achieve reductions in power consumption and low-noise operation.

[Configuration of the Folding Processing Section]

As described previously, the folding processing section48is comprised of first, second, third and fourth rollers49,41,50,64coming into press-contact with one another. Then, with the first roller49positioned in the center, the second roller41, third roller50and fourth roller64are disposed in this order along the rotation direction of the roller49. Further, between the third roller50and the fourth roller64is disposed a guide member39for guiding a folded sheet along the periphery of the first roller49.

Then, a sheet undergoes first folding in the press-contact portion Np1of the second roller41and the first roller49, the sheet undergoes second folding in the press-contact portion Np2of the first roller49and the third roller50on the downstream side, and then, the folded sheet undergoes folding enhancement in the press-contact portion Np3of the first roller49and the fourth roller64.

The apparatus configuration of the above-mentioned folding processing section48will be described below. “44” shown inFIG. 8Adenotes the apparatus frame, andFIG. 8Ashows the front side of mutually opposite front and back side frames (front and back in the sheet ofFIG. 8) of the apparatus housing. Each of the rollers49,41,50and64is rotatably supported between the front and back side frames (hereinafter, the pair of front and back side frames are simply referred to as the “apparatus frame”)44.

At this point, the first roller49is supported by the apparatus frame44via a first bracket member45, and concurrently therewith, the fourth roller64is supported by the apparatus frame44via a second bracket46. Further, the guide member39is supported by the second bracket member46.

This is because the first bracket member45separates the first roller49from the second and third rollers41,50, and the second bracket member46separates the fourth roller64from the first roller49.

Therefore, as shown inFIG. 9, in the invention, the position relationship of the first to fourth rollers49,41,50,64is configured as described below. On the periphery of the first roller49, the second and third rollers41,50are brought into press-contact with the right hemisphere portion (angular interval within 180 degrees), and the fourth roller64is brought into press-contact with the left hemisphere portion (angular interval beyond 180 degrees). InFIG. 9, with reference to the vertical line z-z, the second and third rollers41,50are brought into press-contact with the right side within 180 degrees, while the fourth roller64is brought into press-contact with the left side within 180 degrees.

From such an arrangement relationship, in other words, using the vertical line z-z passing through the circle center of the first roller49as a base point, the second roller41and third roller50are disposed around the periphery of the first roller at angular positions in the range of 0 to 180 degrees, and similarly, the fourth roller64is brought into press-contact at an angular position in the range of 180 degrees to 360 degrees. By this means, the second and third rollers41,50are fixed to the apparatus frame, the first and fourth rollers49,64are shifted in position, and it is thereby possible to release press-contact in three locations at the same time. Further, by placing the second and third rollers41,50in the right hemisphere portion of the first roller49, and further placing the fourth roller64in the left hemisphere portion, it is possible to configure the roller mechanism to be small and compact.

Therefore, the second and third rollers41,50are bearing-supported by the apparatus frame44at an angular interval of 180 degrees or less. InFIG. 9, the rotary shaft41xof the second roller41is bearing-supported by the apparatus frame44to be rotatable, and similarly, a rotary shaft50xof the third roller50is also bearing-supported.

Meanwhile, the first roller49is bearing-supported by the first bracket member45, and the bracket member45is supported at a spindle45rby the apparatus frame44. The spindle45ris set at the center position to swing the first roller49in the direction in which the roller49separates from the second and third rollers41,50.

Then, the first bracket member45is acted upon by the spring force in the arrow direction shown in the figure from the biasing spring (biasing means)47fixed at its one end to the apparatus frame44, and brings the first roller49into press-contact with the second and third rollers41,50.

Meanwhile, the fourth roller64is attached to the second bracket member46, and the second bracket member46is supported swingably at the spindle by the apparatus frame44. To the second bracket member46is fixed the guide member39, and the guide member39is formed in the shape of a curve for guiding the folded sheet along the periphery of the first roller49in between the third roller50and the fourth roller64.

In the second bracket member64, the position of the spindle is set in the apparatus frame44to be swingable in the direction in which the fourth roller64and the guide member39separate from the first roller49. In the bracket shown in the fig ure, the spindle is set at the rotary shaft50xof the third roller50. The spindle may be set at the position other than the rotary shaft50x.

The fourth roller64is not directly attached to the second bracket member46, and is bearing-supported by the biasing lever38attached to the bracket. As shown inFIG. 8A, in the biasing lever38, the front end axially supports the fourth roller64, the center portion is axially supported at the spindle38rby the second bracket member46to be rotatable, and a biasing spring52engages in the base end portion. The biasing spring52is at its one end fixed and supported by the second bracket member46, and acts the spring force in the arrow direction on the biasing lever38. By this spring force, the fourth roller64is brought into press-contact with the first roller49.

Then, when the first bracket member45swings in a clockwise direction inFIG. 9on the spindle45r, the first roller49separates from the second and third rollers41,50. Meanwhile, when the second bracket member46swings in a counterclockwise direction inFIG. 9on the rotary shaft50x, the fourth roller64and the guide member39separate from the first roller49.

In addition, in this case, after the second bracket46is shifted to the position in the direction in which the fourth roller64separates from the first roller49, it is necessary to shift the first bracket member45to the position in the direction in which the fourth roller64separates from the first roller49. This is because of preventing the fourth roller64from interfering with the movement of the first roller49when the first roller49shifts in the separation direction (seeFIG. 9).

By thus separating the first roller49positioned in the center from the second and third rollers41,50, it is possible to concurrently release press-contact of the first folding press-contact portion Np1and the second folding press-contact portion Np2, and it is thus possible to remove a jam sheet by the simplified structure and operation. Concurrently therewith, it is possible to withdraw the fourth roller64and guide member39in press-contact with the first roller49at the same time in the separation direction. Accordingly, concurrently with the folding press-contact portions, it is possible to withdraw the folding enhancement press-contact portion Np3and the guide member39for the portion Np3in conjunction with each other, and therefore, jam handing is remarkably made ease.

The operating means55is provided in one of the first and second bracket members45,46, and the members are interlocked so that when one of the members is swung, the other member also swings at the same time. In the members as shown in the figure, when the second bracket member46swings on the rotary shaft50x, a cam engagement portion46cprovided in the member46presses an interlocked engagement portion45zof the first bracket member45, and swings the first bracket member45on the spindle45rin the clockwise direction inFIG. 9.

The apparatus as shown in the figure indicates the case that the operating means55is provided in the second bracket member46, the second bracket member46is provided with a latch56for holding the member46in the press-contact position, and when the latch is released, the second bracket member46is able to swing on the rotary shaft50xin the counterclockwise direction inFIG. 9.

The latch56is comprised of a cam lever56aand a latch groove46w. The cam lever56ais provided rotatably on the apparatus frame side, and is integrally provided with an operating lever (first operating lever)56b. Then, in a state ofFIG. 11Ain which the front end of the cam lever56aengages in the latch groove46w, the second bracket member46is positioned in an actuation position (attitude).

Then, when the operating lever56bis operated and the cam lever56arotates in a clockwise direction as shown in the figure, the cam lever front end is disengaged from the latch groove46w, and the second bracket member46rotates freely on the rotary shaft50x(free state).

The second bracket member46is provided with a temporary latch57. For the temporary latch57, one of engagement hooks57a,57bthat mutually engage is disposed on the apparatus frame side, while the other one is disposed on the second bracket member side.

The engagement hook57adisposed on the second bracket member side is provided with an operating lever (second operating lever)57cfor releasing latch engagement. When the operating lever57cis operated to rotate in a clockwise direction in the state as shown inFIG. 11A, the temporary latch57is released, and the second bracket member46rotates freely on the rotary shaft50x.

Thus, the second bracket member46takes attitudes in three stages of engagement position (real latch position) Lp1, first release position (temporary latch position) Lp2, and second release position (free state) Lp3. Then, in the real latch position Lp1, the first to fourth rollers49,41,50,64are set for the state in which the rollers are brought into press-contact with one another. In the temporary latch position Lp2, the first to fourth rollers are set for a loose fit state. In the free state Lp3, the second bracket member46can be swung in free angular positions.

Meanwhile, when the second bracket member46shifts in position on the rotary shaft50xas the center from the engagement position Lp1to the second release position Lp3, the cam engagement portion46cpresses the interlocked engagement portion45zof the first bracket member45. Then, the first bracket member45is interlocked in the clockwise direction inFIG. 8Aon the spindle45r, and swings the bracket member45in the separation direction. By this swing, the first roller49separates from the second and third rollers41,50, and the engagement of the press-contact portions Np1, Np2is released.

For the folding processing section48, in the casing29are disposed the sheet transport path (first transport path)32, folding roller means49,41,50,64, and storage stocker65in this order from the top to the bottom. Then, the first roller49, second roller41, third roller50and fourth roller64for folding enhancement constituting the folding roller means are disposed above the storage stocker65.

Accordingly, when an operator pulls sheets out of the stacker65, there is a fear that the operator touches the roller press-contact portion. At the same time, when a sheet jam occurs in the roller press-contact portion, it is necessary to release the press-contact portion. Therefore, the second bracket member46is provided with a cover member58as described below.

[Configuration of the Cover Member]

The cover member58is to prevent the hand of an operator from being caught in the folding rollers when a jam occurs, and is attached in between the second switchback path35and the second bracket member46. The cover member58is comprised of a resin film member having flexibility, and its base end portion58ais fixed to a guide member of the second switchback path35(seeFIG. 10), while its front end portion58bis engaged and supported at slits58sby pins46pprovided in the second bracket member46.

Then, a pair of second bracket members46are disposed at the opposite end portions in the shaft direction of the folding roller to be opposed to each other, and the cover member58is attached in between the pair of bracket members.

Accordingly, the cover member58covers the storage stocker65and the roller press-contact portions Np2, Np3positioned below when the second bracket member46is in the operating state. Meanwhile, when the second bracket member46is opened, it is configured that the operator is able to approach the roller press-contact portion from the storage stacker65.

[Configuration of a Full Detecting Sensor]

Further, in the second bracket member46is disposed a full detection lever60that detects an uppermost sheet of the storage stacker65. When the operator opens the second bracket member46to handle a jam, there is a fear that the detection lever is broken. Therefore, by integrally opening the detection lever60and second bracket member46, it is intended that the detection lever60withdraws from the work area of the jam handling. Sd shown in the figure denotes a sensor that detects the detection lever60.

The driving mechanism of the apparatus as shown inFIG. 3will be described below according toFIGS. 12 and 13.FIG. 12shows the driving transfer system of the feeding motor Mf,FIG. 13Ashows the state in which the gate stopper43is operated by the feeding motor Mf, andFIG. 13Bshows the state in which the pinch roller42is operated by the feeding motor Mf.

InFIG. 12, a motor rotary shaft100of the feeding motor Mf conveys rotation in the forward direction (CW) and rotation in the backward direction to the rotary shaft40xof the carry-in roller40bvia an intermediate shaft101. The rotary shaft40xconveys to the rotary shaft62yof the carrying-out roller62bvia a transmission belt V1.

By this means, the forward and backward rotation of the feeding motor Mf is conveyed to the carry-in roller pair40a,40band carrying-out roller pair62a,62bas rotation in the sheet discharge direction. CW shown in the figure denotes a transmission system of rotation in the forward direction, and CCW denotes a transmission system of rotation in the backward direction. By gear transfer, the rotation directions of the carry-in roller pair40a,40band the carrying-out roller pair62a,62bare set at one direction.

Further, the rotary shaft100of the feeding motor Mf conveys the rotation in the forward direction to the spindle43xof the gate stopper43via an intermediate shaft102, while conveying the rotation to the spindle42xof the pinch roller42via an intermediate shaft103. The transmission system is to shift in position the gate stopper43and the pinch roller42to the waiting position by the rotation in the forward direction (CW) of the feeding motor Mf, and will be described later including the clutch mechanism.

In rotation of the intermediate shaft101, the rotation in the forward direction (CW) is only conveyed to the folding rollers via a one-way clutch OWC. As shown inFIG. 12, the rotation in the forward direction of the intermediate shaft101is transferred to the first roller49, second roller41, third roller50and folding enhancement roller64by gears. In addition, the folding enhancement roller64is a roller in press-contact with the first roller49(described later). Further, the rotation in the forward direction (CW) and the rotation in the backward direction (CCW) of the feeding motor Mf are conveyed to the rotary shaft67xof the sheet discharge roller67.

[Driving Mechanism of the Gate Stopper and Pinch Roller]

Driving of the gate stopper43and pinch roller42as shown inFIG. 13AandFIG. 13Bwill be described next.FIG. 13Ashows the driving mechanism of the gate stopper43, the gate stopper43swings on the spindle43x, and a lock surface43sat the front end shifts to positions between a lock position positioned in the first transport path32and a waiting position outside the path.

Therefore, the gate stopper43is always biased in the direction of an eccentric cam43bby a spring43a, and shifts in position to the lock position (solid line inFIG. 13A) and the waiting position (dashed line inFIG. 13A) by the eccentric cam43b. Therefore, a cam follower43yis formed at one end of the gate stopper43, and engages in the eccentric cam43b. Then, in the eccentric cam43b, a cam gear43crotating integrally with the cam43bis coupled to a teeth-lacked gear43dby gear. A transmission gear43gof the feeding motor Mf is mated with the teeth-lacked gear43d. The teeth-lacked gear43dand the transmission gear43gmesh with each other so as not to convey driving in the teeth lacking portion. Then, the teeth-lacked gear43dis integrally coupled to a control cam43e.

In the control cam43eare engaged a biasing spring43hand actuation solenoid43SL, the biasing spring43hbiases the teeth-lacked gear43din the transmission direction, and the actuation solenoid43SL is engaged to lock the control cam43eto the non-transmission state by a lock hook43f. Accordingly, rotation of the feeding motor Mf is transferred to the teeth-lacked gear43dby the transmission gear43g, and the eccentric cam43brotates by the rotation. Then, the actuation solenoid43SL is coupled to lock the transmission gear43gand teeth-lacked gear43dto the non-transmission state in the non-energized state, while conveying the rotation of the transmission gear43gto the teeth-lacked gear43din the energized state.

In addition, in the eccentric cam43band the teeth-lacked gear43d, the gear coupling rate is set so that a single rotation of the teeth-lacked gear43drotates the eccentric cam43bhalf rotation (½ rotation). Then, the gate stopper43swinging up and down by the eccentric cam43bis provided with a flag43kand position sensor S4(seeFIG. 13A). Accordingly, the control cam43eintegrally formed in the teeth-lacked gear43dshifts the gate stopper43to positions between the actuation position and the withdrawal position by two rotations.

Then, when the actuation solenoid43SL is controlled from the ON state to the OFF state after the teeth-lacked gear43drotates once, the gate stopper43is positioned in the withdrawal position, and rests in the position. Further, when the actuation solenoid43SL is controlled from the ON state to the OFF state after the teeth-lacked gear43drotates twice, the gate stopper43shifts from the actuation position to the withdrawal position by first one rotation, and returns from the withdrawal position to the actuation position by next one rotation. The position sensor S4is an abnormality detecting sensor that detects a state in which the gate stopper43is in the withdrawal position.

In such a configuration, the feeding motor Mf conveys the rotation of the motor to the eccentric cam43bin the forward rotation. In the backward-direction rotation, the actuation solenoid43SL is maintained at the non-energized state (OFF state), and driving is not conveyed in the teeth lacking portion of the teeth-lacked gear43d.

The driving mechanism of the pinch roller42shown inFIG. 13Bwill be described next. As described previously, the pinch roller42is attached to an arm42b(roller shift means; the same in the following), and the bracket42bis configured to swing on the spindle42xas the center. Therefore, the pinch roller42is kept always at the actuation position (solid line inFIG. 13B) by the biasing spring42a. A transmission gear42cis coupled to the shaft portion of the arm42bto rotate integrally, and a clutch gear42emeshes with the transmission gear42cvia a transmission gear line42d. A transmission gear42gof the feeding motor Mf is coupled to the clutch gear42evia a torque limiter TLQ.

The clutch gear42eis supported by a planetary lever26swinging on the intermediate shaft103as described previously as the center, and the spindle of the planetary lever is provided with the torque limiter TLQ. “42f” shown in the figure denotes a stopper for locking the clutch gear42eto the non-transmission state. When the transmission gear42grotates by backward-direction rotation of the feeding motor Mf in the state ofFIG. 13B, the planetary lever42hswings in a clockwise direction, and the clutch gear42eattached to the lever26meshes with the transmission gear line42dand conveys rotation of the transmission gear42gto the transmission gear42c.

Then, the arm42bintegrated with the transmission gear42cshifts to the withdrawal position as the dashed-line state inFIG. 13B. Subsequently, the arm42bengages in a stopper42kand is locked in the position. At this point, the transmission gear line42dand the clutch gear42eidle by the torque limiter TLQ, are halted in rotation, and are locked in the state.

Then, when the feeding motor Mf rotates in the forward direction, the transmission gear42grotates in a clockwise direction, and the planetary lever26gear-coupled to the gear42grotates in a counterclockwise direction. In this state, the coupling between the clutch gear42eand the transmission gear line42dis released, and the clutch gear42eand the transmission gear line42dare locked in the state by the torque limiter TLQ.

Accordingly, in the forward-direction rotation of the feeding motor Mf, the rotation of the transmission gear42gis not conveyed to the transmission gear42cof the arm42b, and the pinch roller42is maintained at the state (the actuation position; solid line inFIG. 13B) in press-contact with the second roller41in the first transport path32by action of the biasing spring42a.

Meanwhile, when the feeding motor Mf rotates in the backward direction, the transmission gear42grotates in a counterclockwise direction, the clutch gear42eof the planetary lever26engages in the transmission gear line42dby the rotation, and the pinch roller42shifts in position to the withdrawal position (dashed line inFIG. 13B) withdrawn from the first transport path32and is locked in the state.

[Open/Close Operation of the Upper Unit]

The unit configuration of the gate stopper43will be described according toFIG. 13A. The gate stopper43, spindle43xand biasing spring43aare attached to the upper unit29A, and to the lower unit29B are attached the eccentric cam43bfor moving the gate stopper43up and down, the cam gear43cfor driving and rotating the cam, the teeth-lacked gear43d, the transmission gear43gand the feeding motor Mf for driving the cams and gears.

Then, in opening and closing the upper unit29A around the hinge shaft28, required is an engagement mechanism with the eccentric cam43bon the lower unit29B side. The open/close mechanism will be described later according toFIG. 15.

Similarly, the unit configuration of the pinch roller42will be described according toFIG. 13B. The pinch roller42, arm42b, spindle42xof the arm, and biasing spring42aare attached to the upper unit29A, and concurrently, the gear42cprovided in the spindle42xand the transmission gear line42dof the gear are also attached to the upper unit29A. Meanwhile, to the lower unit29B are attached the clutch gear42emeshing with the transmission gear line42d, planetary lever26, torque limiter TLQ, transmission gear42gand feeding motor Mf for driving them.

Then, in opening and closing the upper unit29A around the hinge shaft28, required is the engagement mechanism for the transmission gear line42dattached to the upper unit29A and the clutch gear42eattached on the lower unit29B side. The open/close mechanism will be described later according toFIG. 15.

FIGS. 15 to 17are explanatory views of open/close operation of the upper unit29A.FIG. 15shows the operating state in which the upper unit29A is closed,FIG. 16shows an open state in which the upper unit29A is opened by a predetermined angle θ, andFIG. 17shows an intermediate state in opening/closing the upper unit29A.

FIG. 15shows the unit closed state, and the cam follower43yand eccentric cam43bof the gate stopper43are engaged with each other so as to move the gate stopper43up and down by rotation of the cam. Further, the gear42cfor moving the pinch roller43up and down, and the transmission gear line42dof the gear mesh with the clutch gear42e. In this state, each of the gate stopper43and pinch roller42moves up and down by the driving force conveyed from the feeding motor Mf.

FIG. 16shows the unit open state. The cam follower43yof the gate stopper43and the actuation lever63yof the path switching means63are hinge-rotated the predetermined angle θ, and in this state, the cam follower43yis in a position separate from the eccentric cam43b, while the actuation lever63yis in a position separate from the link lever60(engagement release state). Further, the pinch roller42and the transmission gear line42dfor moving the roller up and down are hinge-rotated the predetermined angle θ, and in this state, the transmission gear line42dis in a position separate from the clutch gear42e(engagement release state).

Then, as shown inFIG. 15, in the eccentric cam43bthat engages in the cam follower43yis formed a guide surface43zfor guiding the cam follower43yto the cam surface. The guide surface43zis formed in the shape of a cone with a slope for guiding the cam follower43yto the cam surface during the process of shifting (close operation) to the closed state (the state inFIG. 15) from the state in which the cam follower43yengages in the guide surface43zin the semi-open state of the upper unit29A as shown inFIG. 17.

In other words, in the eccentric cam43bis formed the guide surface43zfor guiding the cam follower43yto the cam surface, and the guide surface43zis formed to guide the cam follower43yto the cam surface when the upper unit29A swings and moves around the hinge shaft28.

Similarly, as shown inFIG. 14, in the link lever60that engages in the actuation lever63yis formed a guide surface60zin the shape of a cone for guiding the actuation lever63yto the engagement surface, and the guide surface60zis formed to guide the actuation lever63yto the engagement surface when the upper unit29A swings and moves around the hinge shaft28.

Further, the clutch gear42efor moving the pinch roller42up and down is attached to the planetary lever26as described previously, and the lever26swings on the rotary shaft103from the solid-line state to the dashed-line state inFIG. 13B. In such a configuration, as shown inFIG. 15, the planetary lever26is provided in the rotary shaft103attached to the lower unit29B. The planetary lever26is provided with a sloped cam surface26zthat engages in a cam gear42iattached to the upper unit29A.

Then, in opening and closing the upper unit29A around the hinge shaft28, the clutch gear42eand the planetary lever26attached to the gear are shifted from the solid-line state to the dashed-line state inFIG. 13B.

In other words, by the open/close operation of the upper unit29A, the clutch gear42eattached to the lower unit29B is shifted from the transmission state to non-transmission state. By this means, the transmission gear42dprovided in the upper unit29A and the clutch gear42eare engaged and released. Accordingly, when the sloped cam surface26zof the planetary lever26is disposed in a position for engaging in the cam gear42iof the upper unit A, the cam gear42iconstitutes an interlock member for actuating the planetary lever26. Alternately, other than the cam gear42i, an interlock member (cam actuator) may be provided in any component of the upper unit A or particularly in the upper unit A, and be configured to engage in the sloped cam surface26z.

Thus, the transport control means such as the gate stopper43and pinch roller42in the upper unit29A are coupled to the feeding motor Mf disposed in the lower unit29B by the transmission mechanism, engagement/release of the transmission mechanism is interlocked with the open/close operation of the upper unit29A, the motor is thereby shared as the driving motor of the folding roller pair of the lower unit29B, and it is thus possible to simplify the driving mechanism.

[Driving Mechanism of the Shift Motor]

Described next is the driving mechanism of the first folding deflecting means53and the second folding deflecting means54as described previously. As shown inFIG. 18AandFIG. 18B, in the first folding deflecting means53, the driven roller53aand the curved guide53bare supported by the up-and-down member53cmoving up and down in a predetermined stroke. The up-and-down member53cis provided with an actuation lever85aswingable on a spindle85xas the center to engage in the member53c. In other words, in the up-and-down member53csupported by the apparatus frame in a guide rail (not shown) to be able to move up and down, a cam groove53dis provided, and is disposed so that the front end of the actuation lever85aengages in the cam groove53d.

Then, the actuation lever85ais coupled to the spindle85xvia a spring clutch85d. Concurrently therewith, the spindle85xis provided with a pulley85b, and rotation of the shift motor MS is conveyed to the pulley85bvia a transmission belt85c. Then, the spring clutch85dis set to convey the rotation of the shift motor MS from the spindle85xto the actuation lever85a. Concurrently therewith, when the load of predetermined torque or more is imposed, the spring clutch85didles with respect to the spindle85x, and is configured not to convey the rotation of the shift motor MS to the actuation lever85a.

Accordingly, when the shift motor MS rotates in the forward direction, the actuation lever85arotates from the state ofFIG. 18Ato the state ofFIG. 18Bin a clockwise direction shown in the figure, and after the driven roller53acomes into contact with the periphery of the first roller49, the spring clutch85didles. Then, when the shift motor MS rotates in the backward direction, the actuation lever85arises from the state ofFIG. 18Bto the state ofFIG. 18A. After the up-and-down member53cstrikes the stopper53e, the spring clutch85didles and the state is locked as shown in the figure. In addition, a limit sensor Ls is disposed in the this position, and the rotation of the shift motor MS is halted by a state signal such that the up-and-down member53cshifts to a predetermined stopper position.

Meanwhile, in the second folding deflecting means54, similarly, the up-and-down member54cis supported by the apparatus frame to move up and down in a predetermined stroke, and is provided with the driven roller54aand curved guide54b. As described previously, the up-and-down member54cis provided with a rack54rthat meshes with a pinion54p. Then, the shift motor MS is coupled to the pinion54pvia a spring clutch86a. The spring clutch86ais set to convey the rotation of the shift motor MS within predetermined torque, while idling at the predetermined torque or more.

In addition, in the first folding deflecting means53and the second folding deflecting means54, the up-and-down member53cshifts in position from the withdrawal position to the actuation position by the forward-direction rotation of the shift motor MS, and by the rotation in this direction, the up-and-down member54cof the second folding deflecting means shifts in position from the actuation position to the withdrawal position. Alternately, in the backward-direction rotation of the shift motor MS, the up-and-down member54cof the second folding deflecting means54shifts in position from the withdrawal position to the actuation position, and by the rotation in this direction, the up-and-down member53cof the first folding deflecting means53shifts in position from the actuation position to the withdrawal position. Thus, the first folding deflecting means53and second folding deflecting means54are configured to shift to positions between the actuation position and the withdrawal position in a relatively opposite manner by forward and backward rotation of the shift motor MS.

As shown inFIG. 3, a first sensor S1for detecting an end edge of a sheet is disposed in the first transport path32, and detects the end edge (front end and rear end) of the sheet carried in the first switchback path34. Further disposed is a second sensor S2for detecting the end edge of the sheet carried in the second switchback path35. The first sensor S1and second sensor S2detect the end edge of the sheet to calculate the fold position of the sheet, and the action of the sensors will be described later together with folding forms described later.

A sheet folding method by the above-mentioned folding processing means will be described next according toFIG. 22A,FIG. 22B,FIG. 22C,FIG. 22DandFIG. 22E. In a normal sheet with the image formed, there are cases that the sheet is folded in two or three for a letter finish. Further, in folding in three, there are cases of outward three-folding and inward three-folding.FIG. 22Ashows an aspect of inward three-folding,FIG. 22Bshows an aspect of outward three-folding, andFIG. 22Cshows an aspect of Z-folding.

Then, in the case of two-folding, the sheet fed to the second transport path33is folded in a ½ position of the sheet size or in a ½ position with a margin left in the sheet end portion by the first and second rollers49,41(first folding).

Meanwhile, in the case of three-folding, the sheet fed to the second transport path33is folded in a ⅓ position of the sheet size by the first and second rollers49,41(first folding). The first and third rollers49,50fold the remaining sheet in a ⅓ position of the folded sheet (second folding) to feed to the third transport path36.

Further, in the case of three-folding, when inward three-folding is performed as shown inFIG. 22A, the sheet fed to the second transport path33is folded in a ⅓ position on the sheet rear end side by the first and second rollers49,41and next, is folded in a ⅓ position on the sheet front end side. Similarly, in the case of outward three-folding, the sheet fed to the second transport path33is folded in a ⅓ position on the sheet front end side by the first and second rollers49,41and next, is folded in a ⅓ position on the sheet rear end side.

Furthermore, in the case of three-folding, when Z-folding as shown inFIG. 22Cis performed, the sheet fed to the second transport path33is folded in a ¼ position on the sheet rear end side by the first and second rollers49,41and next, is folded in a ½ position of the sheet.

Moreover, there is the case that the fold width of three-folding is widened according to the envelop size to leave the margin. In the case of performing inward three-folding as shown inFIG. 22D, the sheet is folded in a position slightly closer to the rear end side than the ⅓ position of the sheet size (first folding), and next, is folded in a position of the substantially same width as the width of the first-folded sheet on the sheet front end side (second folding). Similarly, in outward three-folding as shown inFIG. 22E, the sheet is folded in a position slightly closer to the front end side than the ⅓ position on the sheet front end side, and next, is folded in a position of the substantially same width as the width of the first-folded sheet on the sheet rear end side (second folding). In other words, in the case of leaving the margin in the three-folded sheet, the sheet is folded so that the side of the second-folded sheet is long.

The control means95for above-mentioned sheet folding is configured as described below. The sheet folding apparatus B as described previously is mounted with a control CPU, or a control section91of the image formation apparatus A is provided with a folding processing control section. Then, the control section is configured to enable the following operation.

First, the first switchback path34and second switchback path35of the second transport path33are provided with stopper means (not shown) for regulating the position of the sheet front end or sensor means (S1and S2shown in the figure) for detecting the position of the sheet front end. In the apparatus as shown in the figure, the first sensor S1is disposed in the first switchback path34, and the second sensor S2is disposed in the second switchback path35. Then, the control means95is configured to calculate timing at which the fold position of the sheet arrives at a predetermined position from the sheet size information sent from the image formation apparatus A and a detection signal from the sensor S1(S2).

Then, the operation will be described according to the control block diagram shown inFIG. 23. In the image formation apparatus A, a control CPU91is provided with a control panel15and mode setting means92. The control CPU91controls a paper feed section3and image formation section7, corresponding to image formation conditions set in the control panel15. Then, the control CPU91transfers data and commands such as “post-processing mode”, “job finish signal” and “sheet size information” required for post-processing to the control section95of the post-processing apparatus C.

The control section95of the post-processing apparatus C is a control CPU, and is provided with a post-processing operation control section95a. Then, detection signals of the first sensor S1and second sensor S2are conveyed to the control CPU95. Meanwhile, the control CPU95conveys “ON”/“OFF” control signals to the stopper driving means (solenoid43SL) provided in the gate stopper means43and the path switching means63.

Then, for the control CPU95, folding processing execution programs are stored in ROM96to control the feeding motor Mf (not shown), shift motor MS, stopper driving means (solenoid43SL) and path switching means63so as to execute the folding forms as described previously. Further, RAM98stores data to calculate the fold of the sheet in fold position calculating means97, and actuation timing time of the shift motor Ms as data.

The fold position calculating means97is comprised of a computing circuit for calculating a fold position (dimension) from the sheet front end (front end in the sheet discharge direction), from the “sheet length size”, “folding form” and “margin dimension”. For example, in the two-folding mode, the sheet is folded in a ½ position in the sheet discharge direction, or a ½ position with a beforehand set margin left. For example, calculation of the fold position is obtained by calculating [{(sheet length size)−(margin)}/2]. Further, in the three-folding mode, for example, the fold position is calculated corresponding to the folding form such as letter folding (inward three-folding, outward three-folding) and filing folding (Z-folding, outward three-folding).

The action in the configuration of the sheet folding apparatus B will be described.FIG. 19Ashows a state in which a sheet entering the carry-in entrance30undergoes register correction, andFIG. 19Bshows a state in which the sheet is carried in the first switchback path34for first folding.FIG. 20Ashows a state in which the sheet is folded in the first folding position Np1,FIG. 20Bshows a state in which the folded sheet is carried in the second switchback path35,FIG. 21Ashows a state in which the sheet is folded in the second folding position Np2, andFIG. 21Bshows is a state in which the folded sheet is carried out.

InFIG. 19A, a sheet is guided to the carry-in entrance30, and fed to the downstream side by the carry-in roller pair40. Then, the sheet front end is locked by the gate stopper43, and the sheet is curved and deformed in the shape of a loop inside the register area, and is aligned in the front end.

InFIG. 19B, when the gate stopper43withdraws from first transport path32, the sheet is fed to the downstream side in the first transport path32by the above-mentioned sheet transport mechanism. Then, the control means95controls the path switching means63so as to guide the sheet to the first switchback path34from the first transport path32as shown inFIG. 19B.

Thus, the sheet is carried in the first switchback path34by the pinch roller42and the second roller41. In addition, in the first transport path32, the first sensor S1is disposed on the downstream side of the pinch roller42and the second roller42, and detects the sheet front end carried in the first switchback path34.

InFIG. 20A, based on a signal such that the first sensor S1detects the sheet front end, the control means95shifts the up-and-down member53cof the first folding deflecting means53from the waiting position to the actuation position at timing at which the fold position of the sheet is shifted to a predetermined position. Thus, the sheet in the first transport path32is deformed in the shape of a V toward the first nip portion Np1. Then, when the driven roller53aattached to the up-and-down member53ccomes into press-contact with the periphery of the first roller49, the sheet front end side is fed in the opposite direction (rotation direction of the first roller).

Meanwhile, the sheet rear end side feeds the sheet toward the first nip portion Np1by transport force of the pinch roller42and the second roller41. At this point, the curved guide surface of the curved guide53bregulates the sheet to follow the roller periphery of the second roller41.

Accordingly, the sheet is fed toward the first folding position Np1on the front end side by the driven roller53aand on the rear end side by the pinch roller42and the second roller41, and up-and-down timing of the up-and-down member53cis to calculate the fold position. Therefore, the control means95beforehand sets the velocity for shifting the sheet by the pinch roller42and the second roller41and the timing (particularly, timing at which the driven roller53ccomes into contact with the periphery of the first roller49) for shifting the driven roller53ato the actuation position from the waiting position at optimal values by experiments.

Then, the curved guide surface of the curved guide53bguides the sheet to follow the periphery of the opposed second roller41in synchronization with the shift of the driven roller53afrom the waiting position to the actuation position, and therefore, there is no fear that the fold position of the sheet changes every time.

InFIG. 20B, the sheet folded in the ½ position (two-folding), ⅓ position (three-folding) or ¼ position (three-folding) in the first nip portion Np1is provided with the transport force by the first nip portion Np1and fed to the downstream side. Then, the control means95positions the up-and-down member54cof the second folding deflecting means54in the actuation position in the two-folding mode, or in the waiting position in the three-folding mode.FIG. 20Bshows control of the three-folding mode. In two-folding, the up-and-down member54cis positioned in the actuation position, and the folded sheet is guided to the second nip portion Np2beginning with the front end, and is fed to the carrying-out exit31on the downstream side.

Then, in the three-folding mode, the control means95positions the up-and-down member54cof the second folding deflecting means54in the waiting position as shown inFIG. 20B. Thus, the sheet fed from the first nip portion Np1is fed to the second switchback path35beginning with the front end. Then, the second sensor S2detects the sheet front end (fold position).

InFIG. 21A, with reference to a detection signal of the second sensor S2, in a stage in which the fold position for second folding arrives at a predetermined position, the control means95shifts the up-and-down member54cof the second folding deflecting means54from the waiting position to the actuation position. Then, the sheet inside the second switchback path35is fed in the opposite direction in a stage in which the driven roller54ccomes into contact with the periphery of the third roller50.

By this means, the sheet is guided to the second nip portion Np2by the front end side sending the sheet by the driven roller54aand the rear end side sending the sheet by the first nip portion Np1in respective opposite directions. In addition, in this case, the shift timing of the up-and-down member54cfrom the waiting position to the actuation position is the same as in the case of the first folding deflecting means53as described previously, and the action of the guide member54bis also the same as in the case.

InFIG. 21B, in the folded sheet fed to the second folding position (second nip portion) Np2, the fold is reliably folded by the folding enhancement roller64coming into press-contact with the first roller49, and the sheet is carried to the sheet discharge path36. Then, the control means95feeds the folded sheet to the sheet discharge path37or feeds the sheet back to the first transport path32corresponding to the beforehand set sorting form. In the apparatus as shown in the figure, in inward three-folding and outward three-folding of the letter folding form with no need of binding in the post-processing apparatus C, the control means95controls a path switching flapper38to guide the sheet from the sheet discharge path37to the storage stacker65.

Further, in the two-folding mode and three-folding mode of ¼ Z-folding or the like for filing or with the need of the post-processing such as bookbinding processing, the sheet is carried to the first transport path32from the sheet discharge path36, and fed to the post-processing apparatus C from the carrying-out exit31.

[Folding Operation in the Two-Folding Mode]

In the above-mentioned folding operation, in the mode for folding the sheet in two, as shown inFIG. 24, the control means95receives a mode instruction signal of whether or hot to perform folding processing concurrently with a sheet discharge instruction signal from the image formation apparatus A. Next, the control means95calculates the fold position in the fold position calculating means97(St01). Then, in the two-folding mode (St02), the first sensor S1detects the sheet front end (St03). After a lapse of sheet feeding time corresponding to the sheet length calculated in the fold position calculating means97from the detection signal (St04), the control means95shifts the first folding deflecting means53from the waiting position to the actuation position (St05). This shift is controlled by rotation of the shift motor MS.

In the process during which the up-and-down member53cof the first folding deflecting means53shifts to the actuation position, as described inFIG. 20A, the sheet in the first transport path32is distorted toward the first nip portion Np1with reference to the fold position. Then, when the driven roller53aof the first folding deflecting means53comes into contact with the periphery of the first roller49, the sheet is drawn and inserted in the first nip portion Np1beginning with the fold position.

At this point, in the two-folding mode, after a lapse of predicted time that the fold of the sheet is inserted in the first nip portion Np1with reference to a detection signal from the first sensor S1(St06), the control means95shifts the second folding deflecting means54to the actuation position (St07). The predicted time is set at time elapsed before the front end of the folded sheet arrives at the curved guide54bafter the fold position of the sheet is inserted in the first nip portion Np1. Accordingly, the front end of the folded sheet is guided by the curved guide surface of the curved guide54band is brought along the second roller periphery.

Concurrently therewith, since the driven roller54apositioned in the actuation position rotates according to rotation of the third roller50, even when the front end of the folded sheet is curled in the direction departing from the second nip portion Np2, the sheet is reliably guided to the second nip portion Np2by the rotation of the driven roller54aand third roller50.

Then, the control means95carries the folded sheet, which is fed from the second nip portion Np2to the sheet discharge path36, to the first transport path32from the sheet discharge path36. Next, the control means95prepares for processing of a subsequent sheet in a state in which the second folding deflecting means54is positioned in the actuation position (St08). In the apparatus as shown in the figure, in relation to the first folding deflecting means53positioned in the waiting position, the second folding deflecting means54shifting to positions in a relatively opposite manner is positioned in the actuation position, but it is also possible to configure so that the second folding deflecting means54shifts to the waiting position by a detection signal of a sheet discharge sensor S3disposed in the sheet discharge path36.

[Folding Operation in the Three-Folding Mode]

In the mode for folding the sheet in three, as described inFIGS. 19 to 21, the control means95receives a mode instruction signal of whether or not to perform folding processing concurrently with a sheet discharge instruction signal from the image formation apparatus A. Next, the control means95calculates the fold position in the fold position calculating means97(St01). Then, in the three-folding mode (St09), the first sensor S1detects the sheet front end (St10).

After a lapse of sheet feeding time corresponding to the sheet length calculated in the fold position calculating means97from the detection signal (St11), the control means95shifts the first folding deflecting means53from the waiting position to the actuation position (St12). This shift is controlled by rotation of the shift motor MS.

In the process during which the up-and-down member53cof the first folding deflecting means53shifts to the actuation position, as described inFIG. 20A, the sheet in the first transport path32is distorted toward the first nip portion Np1with reference to the fold position. Then, when the driven roller53aof the first folding deflecting means53comes into contact with the periphery of the first roller49, the sheet is drawn and inserted in the first nip portion Np1beginning with the fold position. At this point, in the three-folding mode, the control means95waits for the second sensor S2to detect the sheet front end (St13).

After a lapse of predicted time that the second-folding fold position of the sheet arrives at a predetermined position with reference to a detection signal such that the second sensor S2detects the sheet front end (St14), the control means95shifts the second folding deflecting means54to the actuation position (St15). The predicted time is set at a calculation value of the fold position calculating means97. Then, the sheet is given the transport force from the driven roller54aand is inserted in the second nip portion Np2. The sheet discharge sensor S3detects the sheet front end, and the sheet is carried out to the first transport path32from the sheet discharge path36, or carried out to the storage stacker65from the sheet discharge path37corresponding to the folding form (St16).

In addition, when the post-processing mode without performing the sheet folding processing is set from the mode setting means92in the above-mentioned step St01, the sheet is fed toward the carrying-out roller pair62. Then, in the first transport path32, the sheet guide61feeds the sheet front end into the nip portion of the carrying-out roller pair62. Accordingly, the sheet is guided to the carrying-out exit (carrying-out portion)31smoothly without undergoing stress of the gate stopper43, pinch roller42and second roller41.

[Configuration of the Sheet Discharge Path]

The folded sheet that is folded in two or three as described above is fed to the sheet discharge path36from the press-contact point of the first and third rollers49,50. Then, the sheet is further folded by the folding enhancement roller (fourth roller)64in press-contact with the first roller49, and guided to the sheet discharge path36. The sheet discharge path36merges with the first transport path32as described previously. The sheet discharge path37branches off from the sheet discharge path36, is provided via the path switching flapper38, and guides the folded sheet to the storage stacker65disposed below the second transport path33.

Accordingly, the sheet with no need of carrying to the post-processing apparatus C e.g. the sheet folded in the letter form such as inward three-folding and outward three-folding is stored in the storage stacker65without being carried to the carrying-out exit31.

Then, in the folded sheet fed to the sheet discharge path36, the sheet to feed to the post-processing apparatus C for post-processing is carried toward the carrying-out exit31by the carrying-out roller62. In addition, in this case, the determination whether or not to perform post-processing is configured to be made by setting the post-processing condition concurrently with the image formation conditions in the control panel15, for example. Then, it is configured that the sheet is carried out to the storage stacker65or carried to the post-processing apparatus C corresponding to the set finish condition.

The image formation apparatus A is provided with the following configuration as shown inFIG. 1. In this apparatus, the paper feed section3feeds a sheet to the image formation section7, the image formation section7prints in the sheet, and the sheet is carried out of the main-body sheet discharge outlet18. The paper feed section3stores sheets of a plurality of sizes in paper cassettes4a,4b, and separates designated sheets on a sheet-by-sheet basis to feed to the image formation section7. In the image formation section7, for example, an electrostatic drum8, and a printing head (laser emitting device)9, developing device10, transfer charger11and fuser12arranged around the drum8are disposed, the laser emitting device9forms an electrostatic latent image on the electrostatic drum8, the developing device10adds toner to the image, the transfer charger11transfers the image onto the sheet, and the fuser12heats and fuses the image.

The sheet with the image thus formed is sequentially carried out of the main-body sheet discharge outlet18. “13” shown in the figure denotes a circulating path, and is a path for two-side printing for reversing the side of the sheet printed on the front side from the fuser12via a main-body switchback path14, then feeding the sheet to the image formation section7again, and printing on the backside of the sheet. Thus two-side printed sheet is carried out of the main-body sheet discharge outlet18after the side of the sheet is reversed by the main-body switchback path14.

“20” shown in the figure denotes an image reading section, scans an original document sheet set on a platen21with a scan unit22, and electrically reads the sheet with a photoelectric conversion element not shown. For example, the image data is subjected to digital processing in an image processing section, and then, transferred to a data storing section16, and an image signal is sent to the laser emitting device9. Further, “25” shown in the figure denotes a feeder apparatus, and feeds original document sheets stored in a stacker24to the platen21.

The image formation apparatus A with the above-mentioned configuration is provided with a control section (controller) not shown, and image formation conditions such as, for example, sheet size designation and color/monochrome printing designation and printout conditions such as number-of-copy designation, one-side/two-side printing designation, and scaling printing designation are set from the control panel15.

Meanwhile, the image formation apparatus A is configured so that image data read by the scan unit22or image data transferred from an external network is stored in the data storing section16, the data storing section16transfers the image data to buffer memory17, and that the buffer memory17transfers a data signal to the printing head9sequentially.

Concurrently with the image formation conditions, a post-processing condition is also input and designated from the control panel15. As the post-processing condition, for example, selected is a “printout mode”, “staple binding mode”, “sheet-bunch folding mode” or the like. The post-processing condition is set for the folding form in the sheet folding apparatus B as described previously.

As shown inFIG. 2, the post-processing apparatus C is provided with the following configuration. This apparatus has a housing68provided with the sheet receiving opening69, sheet discharge stacker70, and post-processing path71. The sheet receiving opening69is coupled to the carrying-out exit31of the sheet folding apparatus B as described previously, and is configured to receive a sheet from the first transport path32or the sheet discharge path36.

The post-processing path71is configured to guide the sheet from the sheet receiving opening69to the sheet discharge stacker70, and a processing tray72is provided in the path. “73” shown in the figure denotes a sheet discharge outlet, and is to collect sheets from the post-processing path71in the processing tray72disposed on the downstream side. “74” shown in the figure denotes a punch unit, and is disposed in the post-processing path71. A sheet discharge roller75is disposed in the sheet discharge outlet73to collect a sheet from the sheet receiving opening69in the processing tray72.

On the processing tray72, sheets from the post-processing path71are switch-back transported (in the direction opposite to the transport direction), and collated and collected using a rear end regulating member (not shown) provided on the tray. Therefore, above the tray is provided a forward/backward rotation roller75for switching back the sheet from the sheet discharge outlet73. Further, the processing tray72continues to the sheet discharge stacker70, and the sheet from the sheet discharge outlet73is supported (bridge-supported) on the front end side by the sheet discharge stacker70and on the rear end side by the processing tray72.

On the processing tray72is disposed a stapler unit77for binding a sheet bunch positioned by the rear end regulating member. “78” shown in the figure denotes aligning means, and aligns the width of the sheet carried onto the processing tray in the direction orthogonal to the transport direction. “79” shown in the figure denotes a paddle rotating body, and is coupled to a rotary shaft of the sheet discharge roller75to be driven to carry the sheet from the sheet discharge roller75toward the rear end regulating member.

“80” shown in the figure denotes sheet bunch carrying-out means, and carries a sheet bunch bound by the stapler unit77to the sheet discharge stacker70on the downstream side. Therefore, the sheet bunch carrying-out means80shown in the figure is comprised of a lever member81axially supported at the base end portion to be swingable, and a sheet end engagement member82.

Then, the sheet end engagement member82is equipped in the processing tray to reciprocate in the sheet discharge direction along the processing tray72, and is coupled to the lever member81. “Mm” shown in the figure denotes a driving motor for causing the lever member81to perform swinging motion. In addition, the sheet discharge stacker70is provided with an elevator mechanism, not shown, which moves up and down corresponding to a load amount of sheets.

In addition, this application claims priority from Japanese Patent Application No. 2010-123210 and Japanese Patent Application No. 2010-225836 incorporated herein by reference.