JP6123433B2 - Post-processing apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a post-processing apparatus that folds a sheet and an image forming apparatus including the same.

In order to make a sheet bundle formed by stacking a plurality of sheets after being printed by a job executed by an image forming apparatus such as a printer into a magazine-like booklet, the target folding position of the sheet bundle is a pair of A post-processing apparatus having a sheet folding function for folding by folding into a nip of a folding roller has been developed.
If the sheet bundle is folded, if it is simply folded, the sheet bundle will naturally gradually open and swell after being folded, and the appearance will deteriorate.

  Therefore, Patent Document 1 discloses a configuration in which the sheet surface from the fold of the sheet bundle to 2 cm is sandwiched between a pair of heating members and heated while being pressed for several seconds to suppress the swelling of the sheet bundle. Is disclosed.

JP 2006-62803 A

In a configuration in which a sheet bundle is sandwiched between a pair of heating members as in Patent Document 1 and the sheet surface from the crease to 2 [cm] is a heating region, the heating member must also be enlarged in accordance with the size of the heating region. However, the heat capacity of the heating member increases and the power consumption required for heating increases.
Also, as the thickness of the sheet bundle increases, the heating member becomes harder to hit the fold that most requires heating, so heat applied to the sheet surface from the heating member is less likely to be transferred to the crease, and it takes time to heat the sheet bundle. And heat efficiency is also deteriorated.

In order to directly heat the fold portion of the sheet bundle, for example, a heating member is disposed downstream of the pair of folding rollers in the sheet conveying direction so that the end of the folded portion of the sheet bundle hits the heating member after being folded. It is conceivable to convey a sheet bundle.
However, since the pair of folding rollers is usually configured such that one roller is urged by one urging member such as a spring to one roller, the number of sheets constituting the sheet bundle increases, and one roller and the other As the thickness of the sheet bundle interposed between the rollers increases, the other roller moves away from the one roller against the urging force of the urging member.

In this way, when the other roller moves away with respect to one roller as the thickness of the sheet bundle increases, the position of the folded portion of the folded sheet bundle in the thickness direction with respect to one roller is also the sheet bundle. The greater the thickness, the further away from one roller.
Therefore, even if the heating member is fixedly arranged on the basis of a sheet bundle made up of a certain number of sheets, when the thicker sheet bundle is folded, the folded portion of the sheet bundle is an amount corresponding to the difference in thickness. Will be displaced in a direction away from one roller with respect to the heating member.

The amount of deviation in the sheet thickness direction with respect to the heating member at the leading end of the folded portion of the sheet bundle varies depending on the thickness of the sheet bundle, and the amount of deviation increases, and the leading end of the folded portion may not contact the heating member. The folded portion of the sheet bundle cannot be heated.
Such a problem generally occurs in a configuration in which the position in the sheet thickness direction of the tip of the folded portion of the sheet bundle is displaced due to the difference in thickness of the sheet bundle. In addition, when sheets with different thicknesses are folded in units of one sheet, the same may occur.

  SUMMARY An advantage of some aspects of the invention is that it provides a post-processing apparatus and an image forming apparatus that can appropriately heat the leading end of a folded portion of a sheet.

In order to achieve the above object, a post-processing apparatus according to the present invention is a post-processing apparatus that folds a sheet with a pair of folding rollers, and a heating member disposed downstream of the pair of folding rollers in the sheet conveying direction; A support means for supporting the heating member so as to be displaceable in the sheet thickness direction according to the thickness of the sheet so that the heating member is in contact with the tip of the folded portion of the folded sheet; and the pair of folding rollers Among the first roller and the second roller that perform, the roller support means that supports the second roller so as to be movable toward and away from the first roller, and the second roller is biased in a direction approaching the first roller roller and biasing means, wherein the support means for the heating element is supported, the support member movable along the sheet thickness direction, engaged with the support member, the heating A positioning member that determines the position of the material in the sheet thickness direction, and the second roller resists the biasing force with respect to the first roller according to the thickness of the sheet. It is characterized in that it is displaced in the same direction along with the displacement when it is displaced in the direction away from each other.

Here, the positioning member may also have good as a rotation shaft of the second roller.

The support means moves the support member so that the support member engages with the positioning member and the heating member is positioned on the sheet conveyance path, and the support member is engaged with the positioning member. It is also possible to provide switching means for switching the heating member to a retreat position where the heating member retreats from the sheet conveyance path.
Here, the folding portion of the sheet after being folded by the pair of folding rollers at a portion where the second roller and the third roller are in contact with the third roller that is in contact with the second roller A pushing member that performs a second folding operation on the sheet by pushing in a portion different from that of the sheet, and the moving direction of the support member from the heating position to the retracted position and the moving direction of the pushing member are It may be parallel.

  Here, the support member is supported by the push member so as to be movable along the push direction, and the support means includes a biasing unit that applies a biasing force in the same direction as the push direction to the support member. The heating member is engaged with the positioning member when the pushing member is pushed, and the supporting member is stopped against the biasing force. The position in the sheet thickness direction may be determined.

Further, the pushing member may be located downstream of the heating member in the sheet conveying direction.
Further, the pushing member and the heating member are positioned closer to the portion where the second roller and the third roller are in contact with each other than the heating member at the tip of the pushing member on the side in contact with the sheet. It may have a relationship.

  A sheet bundle formed by stacking a plurality of the sheets; a stapler that binds the folding position of the sheet bundle with a staple before the sheet bundle is folded by the pair of folding rollers; and the heating member includes a heater and a magnet The staple is made of a material attracted by the magnetic force of the magnet, the heater heats the tip of the folded portion of the sheet bundle, and the magnet is the sheet by the stapler in the heating member. It may be arranged at a position corresponding to the binding position in the sheet width direction to the bundle.

  Here, between the first surface on the upstream side in the sheet conveying direction of the heater and the second surface on the upstream side in the sheet conveying direction of the magnet, the second surface is downstream in the sheet conveying direction with respect to the first surface. When the first surface of the heater is in contact with the leading end of the folded portion of the sheet bundle, the staple needle protruding from the leading end of the folded portion of the sheet is caused by the step. It may be fitted into the resulting space.

  An image forming apparatus according to the present invention is an image forming apparatus including: an image forming unit that forms an image on a sheet; and a post-processing unit that performs post-processing on the sheet on which the image is formed. A post-processing device is provided.

  If configured as described above, the position of the heating member in the sheet thickness direction is displaced so that the heating member is in contact with the tip of the folded portion of the sheet even if the thickness changes for each sheet. The leading end of the folded portion of the sheet can be heated with the leading end in contact with the heating member.

FIG. 2 is a diagram illustrating a configuration of an image forming apparatus and a post-processing apparatus in the first embodiment. It is a figure which shows typically a mode before and after a paper is folded by a paper folding function. It is a figure which shows the detail of a structure of a post-processing apparatus. It is a figure which shows the operation | movement at the time of folding. It is another figure which shows the operation | movement at the time of folding in half. It is another figure which shows the operation | movement at the time of folding in half. It is another figure which shows the operation | movement at the time of folding in half. It is a figure which shows the operation | movement at the time of 3 folding. It is a block which shows the structure of the control part of a post-processing apparatus. It is an enlarged front view when the structure of a 2nd folding knife part and a heating part is seen from an apparatus front side. It is a disassembled perspective view of a 2nd folding knife part and a heating part. It is a figure which expands and shows only a heating part. It is a schematic diagram which shows the positional relationship of a folding roller, a pitch ring, a 2nd heater support member, and a heating part. It is a figure which shows a mode that a heating part is located in a heating position. It is a figure which shows a mode that the position of the sheet thickness direction of a heating part is displaced with the thickness of a sheet bundle. It is a schematic diagram which shows the mode of the heating to the paper bundle by a heating part in order of time. It is a figure which shows the timing chart of the heating operation by a heating part. It is a figure which shows the mode of operation | movement of the 2nd folding knife at the time of 3 folding. It is a flowchart which shows a part of processing content of the heating operation | movement to the paper bundle at the time of folding in half. It is a flowchart which shows the remaining one part of the processing content of the heating operation | movement to the paper bundle at the time of folding in half. FIG. 6 is an exploded perspective view illustrating a configuration of a link mechanism according to a second embodiment. It is a front view when the link mechanism is seen from the direction shown by the arrow K in FIG. It is arrow sectional drawing when a link mechanism is cut | disconnected by the HH line | wire of FIG. It is a figure which shows the structure which concerns on the modification using the magnetic force of a magnet. It is a figure which shows the structure which concerns on the modification which arrange | positions two heaters at intervals in the paper width direction. It is a figure which shows the structure which concerns on the modification which can move a heating part along a paper width direction.

Hereinafter, embodiments of a post-processing apparatus and an image forming apparatus according to the present invention will be described with reference to the drawings.
<Embodiment 1>
(1) Overall Configuration FIG. 1 is a diagram showing the configuration of the image forming apparatus 1 and the post-processing apparatus 2.

As shown in FIG. 1, the image forming apparatus 1 includes an image forming unit 10, a feeding unit 11, a fixing unit 12, and the like, and forms an image on a sheet.
The feeding unit 11 feeds a sheet stored in the sheet feeding cassette 13, here the sheet S, to the conveying path 19 by the feeding roller 14, and the fed sheet S in the direction indicated by the arrow A by the conveying roller 15. 10 to transport.

The image forming unit 10 forms a toner image on the photosensitive drum by an electrophotographic method, and transfers the formed toner image onto the paper S from the feeding unit 11.
The fixing unit 12 fixes the toner image on the sheet S on which the toner image is transferred by heating and pressing. The fixed sheet S is cooled by a cooling unit 16 including a fan, and then discharged (output) by a discharge roller 17 and sent to the post-processing device 2. The image forming apparatus 1 is not limited to an electrophotographic system, and may be an inkjet system, for example.

  The post-processing apparatus 2 includes a paper carry-in unit 21, a conveyance path switching unit 22, paper conveyance units 23, 24, and 25, a staple unit 26, a paper stacking unit 27, a paper folding unit 28, and a paper discharge tray 29a. , 29b, 29c, and the control unit 30 and the like, the paper S output from the image forming apparatus 1 is subjected to post-processing including a staple binding function for stapling and a paper folding function for folding in two or three. It has a function.

(2) About Folding and Trifolding FIG. 2 is a diagram schematically showing a state before and after the sheet is folded by the sheet folding function, and FIG. 2A shows an example of folding in two. Shows an example of tri-folding.
As shown in FIG. 2A, the half-folding is a half-folding with the position where the paper S is divided into two equal parts along the paper transport direction as a target folding position α.

As shown in FIG. 2B, the folding is performed such that the folded SA is folded between the folded SB and the SC with the two folding positions α and β as the target folding positions α and β. In addition, after first folding at the position α (first time), the paper S is folded once again at the position β (second time) and folded in three, which is called a so-called three-fold winding. .
The two-fold or three-fold is not limited to one sheet S, and can be performed on a sheet bundle in which two or more sheets S are stacked.

(3) Configuration of Post-Processing Device 2 FIG. 3 is a diagram showing details of the configuration of the post-processing device 2.
As shown in the figure, the paper carry-in unit 21 receives the paper S output from the image forming apparatus 1 and transports it on the transport path 40 to the transport path switching unit 22 by the transport rollers 41 and 42.
The conveyance path switching unit 22 switches the conveyance destination of the paper S from the paper carry-in unit 21 to one of the conveyance paths 51, 52, and 53 by the switching claw 22a. When the paper S is accommodated in the paper discharge tray 29a without performing post-processing on the paper S, it is switched to the transport path 51, and when the paper S is accommodated in the paper discharge tray 29b, it is switched to the transport path 52. . Further, when the staple binding function or the sheet folding function is performed, the conveyance path 53 is switched. The paper S sent from the paper carry-in unit 21 is sent to the transport path of the switched transport destination.

The paper transport unit 23 transports the paper S sent to the transport path 51 by the transport path switching unit 22 by the transport rollers 61 and 62 and stores it in the paper discharge tray 29a.
The paper transport unit 24 transports the paper S sent to the transport path 52 by the transport path switching unit 22 by the transport rollers 63 and 64 and stores it in the paper discharge tray 29b.
The paper transport unit 25 transports the paper S sent to the transport path 53 by the transport path switching unit 22 toward the paper stacking unit 27 by the transport rollers 65, 66, and 67.

The sheet stacking unit 27 temporarily stores the sheet S conveyed by the sheet conveying unit 25 for post-processing, here, stapling and sheet folding, and includes two stoppers 71 and 72.
The stopper 71 is fixed on a belt 73 that circulates in the direction indicated by the arrow B, and moves as the belt 73 circulates. On the other hand, the stopper 72 is supported so as to be movable in the direction indicated by the arrow C along the linear bar 74.

[In the case of staple binding]
When stapling is performed on a sheet bundle Sb composed of a plurality of sheets S, the stopper 71 stops at a position indicated by a broken line in FIG. In this state, when one sheet S is transported from the transport roller 67, the sheet S descends along the transport path 79, the lower end thereof is regulated by a stopper 71 indicated by a broken line, and the sheet S is belted. 73 along the line. This accommodation operation is sequentially repeated for each sheet of paper S that is conveyed, whereby a plurality of sheets S are stacked on the belt 73. In a state where a plurality of sheets S are stacked, alignment in the width direction with respect to the sheet bundle is performed by an alignment unit (not shown).

When all the sheets S to be stapled are stacked, the staple unit 26 applies staple binding to the bundle of sheets. The bundle of sheets after stapling is conveyed upward by the circumferential running of the belt 73 with the trailing edge being regulated by the stopper 71, and is discharged to the discharge tray 29b via the conveyance roller 64.
[When folding paper]
When the sheet is folded, the stopper 71 stops at the position indicated by the solid line in FIG.

On the other hand, the stopper 72 stops at a predetermined position, for example, a position indicated by a solid line or a broken line in FIG.
By changing the stop position of the stopper 72 according to the paper size, for example, when the paper is folded in half at the center in the transport direction, even if the paper size is different, the position of the center in the transport direction for each paper S Can be stopped so as to face the folding knife 85a, and can be folded at the center position (target folding position α). Further, even with the same size paper S, the folding position is different between the two-folding and the three-folding. Therefore, the sheet S can be folded at the target folding position by changing the stop position of the stopper 72 according to the folding method.

  When one sheet S descends along the conveyance path 79 in a state where the stopper 72 is stopped at a predetermined position corresponding to the sheet size, the lower end of the sheet S is regulated by the stopper 72, and the sheet S is It is accommodated along the guide 75. When folding a bundle of sheets made up of a plurality of sheets S, the accommodating operation is repeated for each sheet S, so that the plurality of sheets S are stacked on the guide 75.

When all the sheets S to be folded are stacked, a sheet folding operation by the sheet folding unit 28 and a heating operation to the leading end of the folding unit are executed as will be described later.
It is also possible to execute an operation of folding the sheet bundle at the target folding position after combining the staple binding and the sheet folding function to staple the portion of the sheet bundle at the target folding position. In this case, the position of the stopper 72 is adjusted so that the sheet bundle stops at a position where the target folding position of the sheet bundle faces the staple unit 26, and after the staple binding, the stopper 72 reaches a position corresponding to the target folding position. After descending, a folding operation is performed on the bundle of sheets after stapling.

Hereinafter, the configuration of the sheet folding unit 28 and the operations at the time of folding and folding in half by the sheet folding unit 28 will be described in order.
(4) Configuration of Sheet Folding Section 28 The sheet folding section 28 includes folding rollers 81, 82, 83, a transport roller 84, a first folding knife section 85, a second folding knife section 86, a heating section 87, A conveyance path switching claw 88, a discharge roller 89, guides 90, 91, and 92 are provided.

Each of the folding rollers 81 to 83 has an elastic layer such as rubber.
The folding rollers 81 and 82 are a pair of rollers used to fold the paper S in two and three, and are in contact with each other, and a nip N1 is formed at the contact portion. Here, a mechanism is employed in which the folding roller 82 presses the folding roller 81 with a compression spring 822 (FIG. 11) as an urging means.

The folding roller 83 is a roller that is used as a pair with the folding roller 82 only when it is folded in three. The folding roller 83 is in contact with the folding roller 82, and a nip N2 is formed at the contact portion. Here, a mechanism is employed in which the folding roller 83 presses the folding roller 82 with a biasing means such as a spring.
Hereinafter, the pair of folding rollers 81 and 82 is referred to as a first folding roller pair 8a, and the pair of folding rollers 82 and 83 is referred to as a second folding roller pair 8b.

The conveyance roller 84 is in contact with the folding roller 83 and conveys the sheet after being folded in three.
The first folding knife portion 85 has a folding knife 85a disposed opposite to the nip N1 of the first folding roller pair 8a across the conveyance path 79, and the folding knife 85a is directed toward the nip N1 in the direction indicated by the arrow D. It moves and performs a push-in operation for pushing the portion of the target folding position α (FIG. 2) of the paper S stored in the paper stacking unit 27 into the nip N1 of the first folding roller pair 8a.

As a result, the portion of the target folding position α of the paper S is drawn into the nip N1 of the rotating first folding roller pair 8a, and the pressing force of the folding rollers 81 and 82 constituting the first folding roller pair 8a The sheet S is folded in half at the target folding position α.
The second folding knife portion 86 sandwiches the conveyance path 99 through which the paper S that has passed through the nip N1 of the first folding roller pair 8a is conveyed, and the folding knife 201 disposed to face the nip N2 of the second folding roller pair 8b. (Pushing member), and the folding knife 201 is moved toward the nip N2 in the direction indicated by the arrow E (corresponding to the pushing direction) at the time of three folding, and the target of the sheet S after being folded at the folding position α. A pushing operation for pushing the portion of the folding position β (FIG. 2) into the nip N2 of the second folding roller pair 8b is performed.

As a result, the target folding position β of the sheet S is drawn into the nip N2 of the rotating second folding roller pair 8b, and the pressing force of the folding rollers 82 and 83 constituting the second folding roller pair 8b The sheet S is folded at the target folding position β.
Each of the rollers such as the folding roller 81 has substantially the same axial length (corresponding to the length in the paper width direction). The lengths of both the folding knife 85a and the folding knife 201 are also substantially the same in the paper width direction, and are slightly shorter than the rollers.

The heating unit 87 is supported by the folding knife 201 and heats the leading end of the folding unit of the paper S that has passed through the nip N1 of the first folding roller pair 8a on the downstream side of the first folding roller pair 8a in the paper transport direction. In doing so, the folding knife 201 is lowered from the retracted position shown in the figure to the heating position (FIG. 14).
The conveyance path switching claw 88 switches the conveyance path 99 between when folded in two and when folded in three, and assumes a posture indicated by a solid line when folded in two and a posture indicated by a broken line when folded in three.

The discharge roller 89 conveys the folded sheet S and discharges it to the discharge tray 29c.
In the present embodiment, the folding rollers 81 to 83, the transport roller 84, and the discharge roller 89 belonging to the paper folding unit 28 are rotationally driven by the folding roller motor 137 (FIG. 9).
[Operation when folding in half]
4-7 is a figure for demonstrating the operation | movement at the time of folding in half.

In FIG. 4, a sheet bundle Sb formed by stacking a plurality of sheets S is accommodated in the sheet stacking unit 27, and before the pushing operation by the folding knife 85a is started, each roller such as the first folding roller pair 8a is moved. The state which the heating part 87 has stopped in the heating position is shown rotating.
In this state, when the pushing operation by the folding knife 85a is started, as shown in FIG. 5, the portion at the target folding position α of the sheet bundle Sb by the folding knife 85a is rotated to the nip N1 of the first pair of folding rollers 8a. Is pushed into the folding position α of the sheet bundle Sb. Thereafter, the folding knife 85a returns to the original position.

By continuing the rotation of the first folding roller pair 8a, the sheet bundle Sb after being folded at the folding position α is conveyed with the folded portion at the top, and the leading end of the folded portion of the sheet bundle Sb passes through the nip N1. After passing, rotation of each roller such as the first folding roller pair 8a is temporarily stopped when a predetermined time Tx has elapsed from the start of the pushing operation by the folding knife 85a (FIG. 6).
During the temporary stop, the heating unit 87 heats the folded portion of the sheet bundle Sb with the leading end of the folding unit in contact with the heating unit 87. The heating time (= Ty) is, for example, ten or more seconds. A suitable heating time is determined in advance according to the paper type, the number of sheets in the paper bundle, and the like.

When the heating of the front end of the folded portion of the sheet bundle Sb is completed, the heating portion 87 returns to the retracted position as shown in FIG. 7, and the rotation of each roller such as the first folding roller pair 8a is resumed.
As a result, the sheet bundle Sb folded in two at the folding position α is transported to the discharge roller 89 on the transport path 99 by the first folding roller pair 8a with the leading end Sa as the head, and then the discharge roller 89 by the arrow F The paper is discharged toward the paper discharge tray 29c in the direction shown.

[Operation when folding in three]
FIG. 8 is a diagram for explaining the operation at the time of folding in three.
In FIG. 8A, the sheet bundle Sb after being folded at the target folding position α is conveyed by the first folding roller pair 8a and guided through the conveyance path switching claw 88 that is switched to the posture for folding in three. 90 shows the state of being guided to 90.

FIG. 8B shows the rollers such as the first folding roller pair 8a in a state where the target folding position β of the sheet bundle Sb is located at a predetermined position facing the nip N2 of the second folding roller pair 8b. It shows a state that the rotation of is stopped.
In FIG. 8C, the pushing operation by the folding knife 201 is started in the state shown in FIG. 8B, and the portion at the target folding position β of the sheet bundle Sb is pushed into the nip N2 of the second folding roller pair 8b. As a result, the rotation of each roller such as the second folding roller pair 8b is resumed.

By resuming the rotation of each roller such as the second folding roller pair 8b, the target folding position β portion of the sheet bundle Sb is drawn into the nip N2 of the second folding roller pair 8b, and a crease is given to the folding position β. . Thereafter, the folding knife 201 returns to the original position.
By continuing the rotation of each roller such as the second folding roller pair 8b, the three-folded sheet bundle Sb is guided to the conveyance roller 84 by the guide 91 with the folding position β at the head, and the conveyance roller 84 84 and the folding roller 83 are conveyed in the direction indicated by the arrow J through the guide 92 and accommodated in the paper discharge tray 29c.

  An open / close cover 31 (FIG. 1) is provided on the side surface of the post-processing apparatus 2 on the paper discharge side to shield the inside of the post-processing apparatus 2 from being opened. When the folded sheet bundle Sb causes a paper jam (jam) during conveyance, the user opens the opening / closing cover 31 and inserts his hand into the inside of the post-processing device 2 from the discharge tray 29c side, thereby jamming. By removing the sheet bundle Sb, the paper jam can be cleared.

In the above description, the operation when the sheet bundle Sb composed of a plurality of sheets S is folded in two and three has been described. For example, the folding operation for one sheet S is also performed in the same manner.
(5) Configuration of Control Unit 30 FIG. 9 is a block diagram showing the configuration of the control unit 30.
As shown in the figure, the control unit 30 includes a central processing unit 101, a timer 102, and a storage unit 103.

The central processing unit 101 includes a program execution unit 111 and a drive control unit 112, and comprehensively controls each unit such as the paper carry-in unit 21 to the paper folding unit 28, and performs post-processing such as stapling and paper folding on the paper S. To make it run smoothly.
The program execution unit 111 executes a predetermined program for post-processing in the post-processing device 2.

The drive control unit 112 outputs a control signal for controlling the path switching motor 131 to the heater 871 to the drivers 120 to 129 for driving the path switching motor 131 to the transport motor 139 and the heater 871.
Here, the path switching motor 131 is used to drive the switching claw 22a (FIG. 3) that switches the transport paths 51 to 53.

The stapler motor 132 is used for stapling a bundle of sheets by driving a staple clincher (not shown: a portion where a staple needle is driven) provided in the staple unit 26 and driving the staple needle into the bundle of sheets.
The first knife motor 133 is used to apply a driving force to the folding knife 85a to execute an operation of pushing the target folding position α portion of the paper S into the nip N1 of the first folding roller pair 8a.

As a drive mechanism that applies a driving force to the folding knife 85a, for example, a cam mechanism that converts the rotational driving force of the first knife motor 133 into a linear force for causing the folding knife 85a to reciprocate in a straight line is used. A direct acting motor can also be used.
The second knife motor 134 applies driving force to the folding knife 201 so as to execute an operation of pushing the portion of the target folding position β of the sheet S into the nip N2 of the second folding roller pair 8b at the time of folding in three. Used for. Further, when heating the leading edge of the paper S folded by the folding knife 85a, a driving force for moving the heating unit 87 from the retracted position to the heating position is applied to the folding knife 201.

  As a driving mechanism for applying a driving force to the folding knife 201, a cam mechanism, a linear motion motor, or the like can be used as described above, but the position of the folding knife 201 is the retracted position for retracting the heating unit 87 from the conveyance path 99. A second position for stopping the heating unit 87 at a heating position on the conveyance path 99, and a third position for pushing the paper S into the nip N2 of the second folding roller pair 8b. The position can be switched to each position. Details of this configuration will be described later.

The first stopper motor 135 is used for moving the stopper 71, and the second stopper motor 136 is used for moving the stopper 72.
The folding roller motor 137 is used to rotationally drive each roller such as the folding roller 81 belonging to the paper folding unit 28.
The switching claw drive actuator 138 is an actuator used to drive the transport path switching claw 88, and includes, for example, a solenoid.

The transport motor 139 is used to rotationally drive the rollers such as the transport rollers 41 and 42 in each unit other than the paper folding unit 28.
The heater 871 is provided in the heating unit 87 and is used as a heat source when heating the leading end Sa of the folded portion of the sheet S folded at the target folding position α.
The timer 102 is used for measuring the predetermined time Tx and the heating time Ty.

The storage unit 103 stores a program executed by the program execution unit 111, data necessary for executing the program, information such as a predetermined time Tx and a heating time Ty.
The central processing unit 101 is configured to be communicable with the image forming apparatus 1, and instructs the execution of post-processing (staple binding, two-fold or three-fold) from the image forming apparatus 1, the paper size and paper to be subjected to post-processing. Information such as the number of sheets is received, and post-processing is executed based on the received instructions and information. Note that a receiving unit that receives an input operation of the information from a user or the like may be provided in the post-processing device 2 and the information may be acquired from the receiving unit instead of the image forming apparatus 1.

The central processing unit 101 includes a processor such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit).
(6) Configuration of Second Folding Knife Unit 86 and Heating Unit 87 FIG. 10 shows the configuration of the second folding knife unit 86 and the heating unit 87 when viewed from the front side of the apparatus with the heating unit 87 positioned at the retracted position. FIG. 11 is an exploded perspective view of the second folding knife part 86 and the heating part 87, and FIG. 12 is an enlarged view of only the heating part 87.

As shown in FIGS. 10 and 11, the second folding knife portion 86 includes a folding knife 201, a knife fixing plate 202, a knife holding member 203, a first heater support member 204, and a second heater support member 205. , A torsion spring 206, tension springs 207, 208 and the like.
In the front view of FIG. 10, only members necessary for explaining the positional relationship among the folding knife 201, the heating unit 87, and the folding rollers 81 to 83 are shown. The same applies to the following front views. In the exploded perspective view of FIG. 11, the configuration of the second folding knife portion 86 is shown only on one end side (device front side) in the paper width direction, and the configuration on the other end side (device rear side) is omitted. However, the other end side has basically the same configuration as the one end side.

The folding knife 201 is long along the paper width direction, and has a blade 201a at its lower end.
The knife fixing plate 202 includes bent pieces 222 that are bent in the sheet conveying direction at both ends of the elongated fixing plate 221 along the sheet width direction. The folding knife 201 is fixed to the fixing plate 221 of the knife fixing plate 202 so that its main surface 201b is in a posture parallel to the paper width direction.

The knife holding member 203 is a plate-like member that is disposed so as to sandwich the knife fixing plate 202 from both ends in the paper width direction, and has a main surface 231 that is orthogonal to the paper width direction and has a device housing (not shown). Fixed to.
The main surface 231 of the knife holding member 203 is provided with a long notch 232 in the direction indicated by the arrow E, and two pins provided on the bent piece 222 of the knife fixing plate 202 are provided in the notch 232. By fitting 223 and 224, the knife fixing plate 202 is supported so as to be movable in the direction indicated by the arrow E with respect to the knife holding member 203.

At the upper end of the knife holding member 203, a bent piece 233 is provided that is bent toward the side where the knife fixing plate 202 is disposed. The bent piece 233 and the bent piece 222 of the knife fixing plate 202 are connected to the tension spring 208. It is connected through.
Due to the tensile force of the tension spring 208, the folding knife 201 fixed to the knife fixing plate 202 is urged against the knife holding member 203 in the direction opposite to the direction indicated by the arrow E.

The first heater support member 204 and the second heater support member 205 are respectively provided on one end side and the other end side of the elongate heating unit 87 along the paper width direction.
The first heater support member 204 is an L-shaped member that is located upstream of the folding knife 201 in the paper conveyance direction and includes a first holding plate 241 that is parallel to the paper conveyance direction and a second holding plate 242 that is orthogonal thereto. is there.

  The second holding plate 242 is parallel to the main surface 201b of the folding knife 201, and the second holding plate 242 is provided with a long notch 244 in the direction indicated by the arrow E. When the two pins 211 and 212 provided on the main surface 201b of the folding knife 201 are fitted, the first heater support member 204 is supported movably in the direction indicated by the arrow E with respect to the folding knife 201. It is configured.

An upper end 247 of the second holding plate 242 and a pin 213 provided on the main surface 201 b of the folding knife 201 are connected via a tension spring 207. The first heater support member 204 is urged in the direction indicated by the arrow E with respect to the folding knife 201 by the tensile force of the tension spring 207.
A long hole 243 extending in the sheet conveyance direction is provided at the center of the first holding plate 241 of the first heater support member 204, and the engagement portion of the second heater support member 205 is provided in the long hole 243. By fitting 251, the second heater support member 205 is supported so as to be movable along the paper transport direction with respect to the first heater support member 204.

An extension portion 246 that extends in the direction opposite to the sheet conveyance direction is provided at an end of the lower portion of the first holding plate 241 on the upstream side in the sheet conveyance direction, and a protrusion 245 is formed on the upper portion of the first holding plate 241. Is provided.
A torsion spring 206 is fitted into the protrusion 245, a second heater support member in which one end of the torsion spring 206 is engaged with the elongated hole 243 and the other end of the torsion spring 206 is fitted into the elongated hole 243. It is engaged with the engaging portion 251 of 205 (FIG. 10). Due to the force of the torsion spring 206 in the opening direction, the second heater support member 205 is urged against the first heater support member 204 in the direction opposite to the paper transport direction.

The second heater support member 205 includes an engaging part 251 and a fixed part 252.
The engaging portion 251 has a rectangular bar shape in cross section, one end side is engaged with the elongated hole 243 of the first heater support member 204, and the other end side is fixed to the fixing portion 252.
The fixing portion 252 is a substantially semicircular member having a diameter larger than that of the engaging portion 251, and is an end of the heating portion 87 in the sheet width direction on the surface opposite to the side on which the engaging portion 251 is fixed. Is fixedly supported.

As shown in FIGS. 12A and 12B, the heating unit 87 is long in the sheet width direction and includes a heater 871 and a substrate 872 that are extremely thin. Specifically, the heating unit 87 has a maximum paper size in the paper width direction, for example, about 350 mm longer than the A4 size paper width, a width of about 5 mm, and a thickness of 0.5 to 0.5. It is about 0.6 [mm].
The heater 871 is a so-called polyimide heater in which a heating element such as stainless steel or nickel alloy having a thickness of about several tens of μm is sandwiched between two polyimide films having a thickness of about several tens of μm, and has low power consumption. However, it is suitable for a heater that locally heats the front end of the folded portion of the paper because the temperature rises quickly and the thermal response is good due to the low heat capacity.

Conductive wires 87u connected to both ends of the heater 871 in the paper width direction are connected to the driver 129 (FIG. 9), and the electric power from the driver 129 is supplied to the conductive wire 87u, whereby the heating element of the heater 871 generates heat. Yes (heater on). Note that the heater 871 is not limited to a polyimide heater, and other heaters may be used.
The substrate 872 is made of, for example, a thin aluminum plate having a thickness of about 0.5 mm, and the heater 871 thinner than this is fixedly supported so as not to be bent. Note that the heater 871 is not limited to the relationship of being positioned downstream of the substrate 872 in the paper conveyance direction, and the heater 871 and the substrate 872 may be in the opposite positional relationship, for example.

Returning to FIG. 11, the pitch ring 830 is engaged with each of one end side and the other end side of the rotation shaft 811 of the folding roller 81 and the rotation shaft 821 of the folding roller 82.
The pitch ring 830 includes a ring portion 831 and two support pieces 832 and 833 extending downward from the lower portion of the ring portion 831.
The ring portion 831 is fitted into the rotation shaft 811 of the folding roller 81 and is provided to separate the heating portion 87 located at the retracted position from the peripheral surface of the folding roller 81. The details of the configuration for separating are described later.

The two support pieces 832 and 833 are spaced apart from each other by a distance corresponding to the diameter of the rotation shaft 821 of the folding roller 82 so that the folding roller 82 can move in the contact / separation direction with respect to the folding roller 81. It functions as a roller support means for supporting the rotary shaft 821 of 82.
A compression spring 822 as a roller urging unit is interposed between the rotation shaft 821 of the folding roller 82 and the apparatus housing 210, and the folding roller 82 supported by the support pieces 832 and 833 is connected to the compression spring 822. The folding roller 81 is pressed by an urging force in a direction indicated by an arrow G (a direction in which the folding roller 82 approaches the folding roller 81). As a result, a pressing force is generated in the nip N1, which is a portion where the folding rollers 81 and 82 are in contact with each other.

As the thickness of the sheet S or the sheet bundle Sb that is folded in half increases, the folding roller 82 is displaced in the direction away from the folding roller 81 against the urging force of the compression spring 822. Therefore, the distance between the axes of the folding rollers 81 and 82 is increased. Lx will increase.
In the configuration as described above, when the heating unit 87 is located at the retracted position (FIG. 10), the driving force by the second knife motor 134 is not applied to the folding knife 201, so that the folding spring 201 is folded by the tensile force of the tension spring 208. The knife 201 is positioned at the highest position (first position) in the movable range of the notch 232 of the knife holding member 203.

With respect to the uppermost folding knife 201, the first heater support member 204 is positioned at the lowest position in the movable range by the notch 244 by the tensile force of the tension spring 207. When the first heater support member 204 is at the lowest position, the heating unit 87 is positioned at the retracted position above the transport path 99 as shown in FIG.
When the heating unit 87 is located at the retracted position, the heating unit 87 is configured to be separated from the folding roller 81 in the sheet conveyance direction. The separation of the heating unit 87 from the folding roller 81 is performed by the cooperation of the fixing unit 252 of the second heater support member 205 and the ring unit 831 of the pitch ring 830 fitted to the rotation shaft 811 of the folding roller 81. Is done.

FIG. 13 shows the positional relationship among the folding rollers 81 and 82, the pitch ring 830, the second heater support member 205, and the heating unit 87 when the heating unit 87 is located at the retracted position and at the heating position. It is a schematic diagram divided and shown. In the figure, members other than the folding rollers 81 to the heating unit 87 are omitted.
When the heating part 87 is located at the retracted position, the fixing part 252 of the second heater support member 205 is in contact with the peripheral surface of the ring part 831 of the pitch ring 830. As described above, the engagement portion 251 of the second heater support member 205 is engaged with the long hole 243 provided in the first heater support member 204 (FIG. 11) and moved in the longitudinal direction (paper conveyance direction). It is freely supported by the first heater support member 204 and is biased in the direction opposite to the paper transport direction by the force in the direction in which the torsion spring 206 opens.

  Therefore, the fixing portion is arranged such that the heating portion 87 is separated from the circumferential surface 815 of the folding roller 81 by a predetermined distance within the movable range in the longitudinal direction of the second heater supporting member 205 by the elongated hole 243 of the first heater supporting member 204. If the diameters of both the 252 and the ring portion 831 are determined in advance, the heating portion 87 is moved against the folding roller 81 against the urging force of the torsion spring 206 as shown in FIG. It can be retracted to a position separated by a predetermined distance downstream in the transport direction.

On the other hand, when the heating part 87 moves from the retracted position to the heating position, the fixing part 252 of the second heater support member 205 is separated from the peripheral surface of the ring part 831 of the pitch ring 830.
Since the second heater support member 205 is urged in the direction opposite to the sheet conveyance direction by the urging force of the torsion spring 206, the fixing portion 252 of the second heater support member 205 is separated from the ring portion 831 of the pitch ring 830. Then, due to the biasing force of the torsion spring 206, the heating unit 87 moves to a position closest to the nip N1 of the folding rollers 81 and 82 within the movable range of the elongated hole 243 of the first heater support member 204. In the drawing, an example in which the moving distance of the heating unit 87 from the retracted position to the heating position in the sheet conveyance direction is U is shown.

When the heating unit 87 is shifted from the retracted position shown in FIG. 10 to the heated position, a driving force by the second knife motor 134 is applied to the folding knife 201. Thereby, the folding knife 201 descends along the direction indicated by the arrow E against the tensile force of the tension spring 208 to the position shown in FIG.
When the folding knife 201 is lowered, the first heater support member 204 is also lowered (moved) together. However, the lower end of the extending portion 246 of the first heater support member 204 is in contact with the rotating shaft 821 of the folding roller 82 along the way. (Engagement) and the lowering of the first heater support member 204 is restricted.

When the lowering of the folding knife 201 is continued in a state where the lowering of the first heater support member 204 is restricted, the first heater support member 204 is pulled by the tension spring 207 shown in FIG. Force acts.
When the folding knife 201 descends to the position (second position) shown in FIG. 14 and stops, the first heater support member 204 is pulled while the lower end of the extension portion 246 is in contact with the rotating shaft 821 of the folding roller 82. The spring 207 is urged in the direction indicated by the arrow E, that is, the direction toward the rotation shaft 821 of the folding roller 82 by the tensile force of the spring 207. In this sense, the tension spring 207 is attached to the first heater support member 204 that supports the heating unit 87 via the second heater support member 205 in the same direction as the pushing direction of the folding knife 201 (the direction indicated by the arrow E). It can be said that it functions as an urging means for applying power.

  By transitioning to this state, the position of the heating unit 87 supported by the first heater support member 204 with respect to the folding roller 82 is determined, and the heating unit 87 is positioned at the heating position without contacting the folding rollers 81 and 82. It becomes like this. In this sense, the second knife motor 134 functions as a switching unit that moves the second heater support member 204, which is a support member that supports the heating unit 87, and switches the position of the heating unit 87 between the heating position and the retracted position. To do.

  The folding roller 82 is displaced in the direction away from the folding roller 81 against the urging force of the compression spring 822 as the thickness of the sheet bundle Sb increases as described above, and thus the folding roller 82 is moved away from the first heater support member 204. By using the positioning member, the position of the first heater support member 204, that is, the heating unit 87 is also displaced in the same direction as the folding roller 82 as the folding roller 82 is displaced in the sheet thickness direction.

FIG. 15 is a diagram illustrating a state in which the position of the heating unit 87 in the sheet thickness direction is displaced depending on the thickness of the sheet bundle Sb. In the case where the number of sheets is n2 (> n1) [sheets] than the case of n1 [sheets]. In this example, the thickness of the sheet bundle Sb is thick, and the difference in thickness appears as a difference dx in the interaxial distance of the folding roller 82 from the folding roller 81.
As shown in the figure, when the number of sheets is n2 [sheets] versus n1 [sheets], when the folding roller 82 is displaced in a direction (downward) away from the folding roller 81 by a distance dx, this As the folding roller 82 is displaced, the position of the heating unit 87 is also displaced in the same direction as the folding roller 82 (downward) in the sheet thickness direction.

The position of the leading end Sa of the sheet bundle Sb in the sheet thickness direction is displaced in a direction (downward) away from the folding roller 81 as the thickness of the sheet bundle Sb is increased. Therefore, the sheet bundle when the thickness of the sheet bundle Sb is increased. The displacement direction of the tip Sa of Sb and the displacement direction of the heating unit 87 are the same direction.
That is, when the thickness of the sheet bundle Sb increases and the position of the leading end Sa of the sheet bundle Sb in the sheet thickness direction is displaced, the heating unit 87 is also displaced in the same direction so as to follow the displacement of the leading end Sa.

Accordingly, the amount of deviation of the leading end Sa of the sheet bundle Sb in the sheet thickness direction with respect to the heating unit 87 can be reduced as compared with the configuration in which the heating unit is fixedly arranged. When the leading end Sa of the sheet bundle Sb hits the heating unit 87 It is possible to prevent the heating from being lost.
In this sense, the first heater support member 204 and the folding roller 82 correspond to the thickness of the sheet bundle Sb so that the heating unit 87 is in contact with the leading end Sa of the folded portion of the folded sheet bundle Sb. Thus, it can be said that the heating unit 87 functions as a supporting unit that supports the heating unit 87 so as to be displaceable in the sheet thickness direction.

  When the folding roller 82 is used as a positioning member for the first heater support member 204, the folding roller 82 is moved away from the folding roller 81 by the pressing force of the folding roller 82 on the rotation shaft 821 by the first heater support member 204. The magnitude of the tensile force of the tension spring 207 that biases the first heater support member 204 and the restoring force of the compression spring 822 that biases the folding roller 82 are determined in advance so as not to be displaced.

When the sheet bundle Sb folded at the target folding position α passes through the nip N1 of the folding rollers 81 and 82 with the folding section at the top while the heating section 87 is stationary at the heating position, the next item In this manner, heating of the leading end of the folded portion of the sheet bundle Sb by the heating unit 87 is performed.
(7) Details of Heating by Heating Unit 87 FIG. 16 is a schematic diagram showing the order of heating of the sheet bundle Sb by the heating unit 87 in time order.

In the drawing, in order to facilitate understanding of the positional relationship between the heating unit 87 and the sheet bundle Sb being conveyed, the heating position of the heating unit 87 is illustrated as being shifted to the downstream side in the sheet conveyance direction from the original position. Yes.
FIG. 16A shows a heating position on the conveyance path 99 by the first folding roller pair 8a (folding rollers 81 and 82) in a state where the sheet bundle Sb folded in two has the leading end Sa of the folded portion at the top. It shows a state of being conveyed toward the heating unit 87 located at (time t1).

FIG. 16B shows a state in which the sheet bundle Sb is stopped in a state where the leading end Sa of the folded portion of the sheet bundle Sb is in contact with the heating unit 87 (time t2). The sheet bundle Sb being transported is stopped by stopping the rotation of the first folding roller pair 8a by stopping energization of the folding roller motor 137.
The heating unit 87 is stationary at a position shifted from the position shown in FIG. This is because, after the leading end Sa of the sheet bundle Sb being conveyed first contacts the heating unit 87, the heating unit 87 is pushed by the sheet bundle Sb until the sheet bundle Sb stops. This is because, while maintaining the contact state with the front end Sa, the first heater support member 204 has moved in the movable range of the elongated hole 243 in the paper conveyance direction against the biasing force in the opening direction of the torsion spring 206.

  Until the sheet bundle Sb after being folded is stopped, the heating unit 87 is in contact with the front end Sa of the folded portion of the sheet bundle Sb against the urging force of the torsion spring 206 and the sheet bundle Sb. By determining the biasing force of the torsion spring 206 to a size that allows it to move integrally along the paper transport direction, the heating unit 87 contacts the front end Sa of the folded portion of the transported paper bundle Sb. Will be maintained.

As a result, even if there is some variation in the transport distance until the sheet bundle Sb stops, the variation is absorbed, and the leading end Sa of the folded portion of the sheet bundle Sb is in contact with the heating unit 87. The tip Sa can be heated.
In the case of adopting this configuration, the size of the movable range P of the heating unit 87 shown in FIG. 16A, that is, the first heater support member 204 can be absorbed so as to absorb the variation in the transport distance until the sheet bundle Sb stops. The length of the long hole 243 in the sheet conveyance direction and the magnitude of the urging force of the torsion spring 206 are determined in advance as appropriate values according to the amount of variation in the conveyance distance until the sheet bundle Sb stops. The size of the length P can be set to about 5 [mm], for example.

FIG. 16C shows a state in which the heating unit 87 is returned from the heating position to the retracted position after the heating by the heating unit 87 is finished (time point t3).
FIG. 16D shows a state in which, after the heating unit 87 returns to the retracted position, the conveyance of the heated sheet bundle Sb is resumed by resuming the rotation of the first folding roller pair 8a (time point t4). .
Thereby, the heating operation by the heating unit 87 with respect to the leading end Sa of the folded portion of the sheet bundle Sb is completed. In the above description, the heating target is the sheet bundle Sb, but the same heating operation is performed on one sheet S.

Note that when the paper bundle Sb or the single paper S after being folded is jammed during the conveyance, the user operates the open / close cover 31 to remove the jammed paper bundle Sb or the paper S as described above. Although it can remove | eliminate, the heating part 87 will be in the state located in the retracted position at this time.
When the heating unit 87 is in the retracted position, as shown in FIG. 10, the heating unit 87 and the folding knife 201 are positioned such that the folding knife 201 is located downstream of the heating unit 87 in the paper conveyance direction, and In the moving direction of the folding knife 201, the tip of the blade 201a is positioned closer to the nip N2 of the second folding roller pair 8b than the heating unit 87 is.

Due to this positional relationship, when the user performs an operation of inserting a hand into the post-processing apparatus 2 to clear a paper jam, the folding knife 201 on the downstream side in the paper transport direction from the heating unit 87 becomes like a wall, It is possible to prevent the user's hand from touching the heating unit 87.
FIG. 17 is a diagram illustrating a timing chart of the heating operation by the heating unit 87.
As shown in the figure, at the time point t0, the first folding roller pair 8a (folding rollers 81 and 82) is rotating, the heater 871 of the heating unit 87 is off (non-energized), and the heating unit 87 is in the heating position. In this state, the sheet folding Sb is pushed by the first folding knife 85 into the nip N1 of the first folding roller pair 8a (corresponding to the state shown in FIG. 4).

A time point t1 immediately after the start of the pushing operation corresponds to a time point t1 shown in FIG. 16A, and the leading end Sa of the folding portion of the sheet bundle Sb conveyed on the conveyance path 99 by the first folding roller pair 8a. Indicates a point in time that has not yet reached the heating section 87.
When a predetermined time Tx elapses from the start of the pushing operation (time t0) (time t2), the rotation of the first folding roller pair 8a is stopped and the heater 871 is turned on (energized). This time point t2 corresponds to the time point t2 shown in FIG.

The predetermined time Tx is from the start of the push-in operation, after the leading end Sa of the folded portion of the sheet bundle Sb conveyed by the first folding roller pair 8a abuts the heating unit 87, and maintains the abutting state. The time required for Sa to reach a reference position (FIG. 16B) corresponding to the center of the elongated hole 243 of the first heater support member 204 in the sheet conveyance direction is determined in advance.
When a predetermined time Ty has elapsed from time t2 (time t3), the heater 871 is turned off (energization is interrupted), and the operation of returning the heating unit 87 from the heating position to the retracted position is started. The time point t3 corresponds to the time point t3 shown in FIG. 16C, and the predetermined time Ty corresponds to the heating time.

When a predetermined time Tz has elapsed from time t3 (time t4), the rotation of the first folding roller pair 8a is resumed. Time t4 corresponds to time t4 shown in FIG. The predetermined time Tz corresponds to the time required for the heating unit 87 to return from the heating position to the retracted position, and is determined in advance.
(8) Operation of folding knife 201 at the time of three folding FIG. 18 is a diagram showing the behavior of folding knife 201 at the time of three folding.

As shown in the figure, when the sheet is folded in three, the folding knife 201 folds in half and the target folding position β of the sheet bundle Sb after heating is pushed into the nip N2 of the second folding roller pair 8b (third position). To position). The pushing position of the folding knife 201 shown in FIG. 18 is lower than the second position when the heating unit 87 is stopped at the heating position (FIG. 14).
While the folding knife 201 is lowered from the first position (the highest position) to the pushing position, the tip of the blade 201a of the folding knife 201 (the tip on the side in contact with the paper S) is the second folding roller pair 8b than the heating unit 87. Therefore, the blade 201a of the folding knife 201 does not contact the sheet bundle Sb and the heating unit 87 does not contact the sheet bundle Sb.

As a result, during the pushing operation of the sheet bundle Sb by the folding knife 201, the heating unit 87 hits the sheet bundle Sb prior to the folding knife 201, and the position of the sheet bundle Sb in the sheet conveyance direction is shifted. It is possible to prevent the position from deviating from the target folding position β.
Further, when the folding knife 201 is lowered to the pushing position, the lower end of the extension portion 246 of the first heater support member 204 comes into contact with the rotating shaft 821 of the folding roller 82 as in the heating position. Therefore, the heating unit 87 is not positioned below the transport path 99, and is prevented from hitting the sheet bundle Sb being folded in three.

The sheet bundle Sb that has passed through the nip N2 of the second folding roller pair 8b is conveyed to the conveying roller 84 by the guide 91 on the conveying path 98 with the target folding position β at the head, and the conveying roller 84 and the folding roller 83 are conveyed. Is further transported downstream in the transport direction.
(9) Processing Contents of Heating Operation at the Time of Folding FIGS. 19 and 20 are flowcharts showing the processing contents of the heating operation to the sheet bundle at the time of folding in half. This process is executed for each heating operation by the central processing unit 101 of the control unit 30. When the sheet is folded in three, the heating operation process shown in FIGS. 19 and 20 is performed in the first folding operation on the sheet bundle Sb, and then the second folding operation is performed on the heated sheet bundle Sb. Executed.

As shown in FIG. 19, when an instruction to perform a folding operation is received from the image forming apparatus 1 (step S1), the folding roller motor 137 starts to rotate (step S2). As a result, the folding rollers 81 to 83 are driven to rotate.
Subsequently, the heating unit 87 is moved from the retracted position to the heating position (step S3). The movement of the heating unit 87 is performed by driving the second knife motor 134.

When all the n (an integer greater than or equal to 1) sheets S to be folded are stacked on the sheet stacking unit 27, the target folding position α of the sheet bundle Sb is set by the first folding roller pair by the folding knife 85a. The pushing operation for pushing into the nip N1 of 8a is started (step S4) (time t0 in FIG. 17). Thereby, the folding of the sheet bundle Sb is started.
Here, the number n of sheets S is acquired from the image forming apparatus 1. Further, the fact that n sheets S are stacked on the sheet stacking unit 27 is performed by counting the number of detections of the sheet S conveyed to the sheet stacking unit 27 by a sheet detection sensor (not shown). .

The timer 102 is activated (step S5), and it is determined whether or not the count value of the timer 102 has become equal to the predetermined time Tx (step S6).
When it is determined that the count value of the timer 102 has become equal to the predetermined time Tx (“YES” in step S6) (time t2 in FIG. 17), the rotation of the folding roller motor 137 is stopped (step S7), and the heating unit 87 is reached. The heater 871 is energized (step S8).

  Accordingly, the conveyance of the sheet bundle Sb after being folded in half by the folding roller pair 8a is stopped, and the leading end Sa is heated by the heating unit 87 in a state where the leading end Sa of the folded portion is in contact with the heating unit 87. (FIG. 16B). In this sense, the control unit 30 functions as a stopping unit that stops the rotation of the folding roller pair 8a in order to stop the conveyance of the folded sheet bundle Sb when executing the process of step S7.

Subsequently, it is determined whether or not the count value of the timer 102 has become equal to a predetermined time (Tx + Ty) (step S9).
When it is determined that the count value of the timer 102 is equal to the predetermined time (Tx + Ty) (“YES” in step S9) (time t3 in FIG. 17), the energization of the heater 871 of the heating unit 87 is cut off (step S10). ). Thereby, heating to the front end Sa of the folded portion of the sheet bundle Sb is completed.

Then, as shown in FIG. 20, an operation of returning the heating unit 87 from the heating position to the retracted position is started (step S11) (FIG. 16C). Thereby, the heating part 87 returns to a retracted position.
Subsequently, it is determined whether or not the count value of the timer 102 is equal to a predetermined time (Tx + Ty + Tz) (step S12).
When it is determined that the count value of the timer 102 is equal to the predetermined time (Tx + Ty + Tz) (“YES” in step S12) (time t4 in FIG. 17), the timer 102 is reset to zero (step S13), and the folding roller The rotation of the motor 137 is resumed (step S14). Thereby, the conveyance of the sheet bundle Sb is resumed (FIG. 16D).

  If it is determined that the heated sheet bundle Sb has passed through the first folding roller pair 8a (“YES” in step S15), the folding roller motor 137 is stopped (step S16), and the process is terminated. The determination that the sheet bundle Sb has passed the first folding roller pair 8a is based on the fact that the trailing end of the sheet bundle Sb in the conveyance direction is detected by a sheet discharge sensor (not shown) provided along the conveyance path 99. Is done.

In the above, the configuration example (steps S7 and S8) in which energization (on) to the heater 871 of the heating unit 87 is started after the folding roller motor 137 is stopped has been described, but the on timing of the heater 871 is the folding roller motor. It is not limited to after 137 stop.
In some cases, the heater 871 is turned on in advance by the time required for the temperature of the heater 871 to rise to a predetermined temperature required for heating the leading end of the folded portion of the sheet bundle Sb. In this case, the heater 871 is turned on earlier than the folding roller motor 137 is stopped.

The on-timing of the heater 871 can be determined based on the temperature rise characteristic of the heater 871, and is the same as, for example, when the first sheet S is stored in the sheet stacking unit 27 or when the pushing operation by the folding knife 85a is started. It can be timing.
As described above, in the present embodiment, when the thickness of the sheet bundle Sb increases and the position in the sheet thickness direction at the front end Sa of the folded portion is displaced, the heating unit 87 is also moved in the same direction so as to follow the displacement. Therefore, as compared with the configuration in which the heating unit is fixedly disposed, the amount of deviation of the heating unit 87 in the sheet thickness direction with respect to the leading end Sa of the folding unit of the sheet bundle Sb is reduced, and the folding unit of the sheet bundle Sb is reduced. It becomes possible to locally heat the tip Sa.

Since the folded portion of the sheet bundle Sb is linear along the sheet width direction, the elongated heater 871 and the substrate 872 constituting the heating unit 87 are matched to the linear shape of the folded portion of the sheet bundle Sb. Can be configured to have a smaller width (length in the sheet thickness direction).
Thereby, the power consumption can be reduced by using the small heater 871, and the heating of the heater 871 is faster due to the lower heat capacity of the heating unit 87 itself, so that the heating of the sheet bundle Sb is started more quickly. The time required from the start to the end of heating can be shortened.

Further, since the position of both the heating unit 87 and the folding knife 201 is switched by the driving force of one driving source (second knife motor 134), the apparatus configuration is simpler than when the driving sources are provided separately. And cost reduction can be achieved.
Further, since the heating unit 87 is configured to move in parallel with respect to the folding knife 201 that moves in the direction intersecting the paper conveyance direction, the heating unit 87 can be disposed at a position closer to the folding knife 201 in the paper conveyance direction. In addition, the moving mechanism of the second folding knife 201 and the heating unit 87 can be made compact in the paper transport direction.

Accordingly, for example, the moving mechanism of the second folding knife 201 and the heating unit 87 can be accommodated without providing a large space around the folding knife 201, and the post-processing device 2 itself is enlarged to secure the accommodation space. Can be prevented.
<Embodiment 2>
In the first embodiment, the configuration example in which the position of the heating unit 87 in the sheet thickness direction is determined by the rotation shaft 821 of the folding roller 82 has been described, but in the second embodiment, the rotation shaft 811 of the folding roller 81 and the folding roller. The position of the heating unit 87 in the sheet thickness direction is determined by using a link mechanism that connects the rotating shaft 821 of 82, which is different from the first embodiment in this respect. Hereinafter, in order to avoid duplication of description, the description of the same contents as those of Embodiment 1 is omitted, and the same components are denoted by the same reference numerals.

  FIG. 21 is an exploded perspective view showing the configuration of the link mechanism 300 according to the second embodiment. In FIG. 21, the configuration of only the front side of the apparatus is shown, and the configuration of the rear side of the apparatus is omitted. However, the same link mechanism 300 as that on the front side of the apparatus is provided on the rear side of the apparatus. Moreover, in this Embodiment 2, it replaces with the 1st heater support member 204 of Embodiment 1, and the 1st heater support member 204a is provided. The only difference from the first heater support member 204 is that the extending portion 246 is not provided.

As shown in FIG. 21, the link mechanism 300 includes arms 301, 302, 303, and 304.
The arms 301 and 302 connect the rotation shaft 811 of the folding roller 81 and the support plate 305, and the arms 303 and 304 connect the rotation shaft 821 of the folding roller 82 and the support plate 305.
The support plate 305 includes a first support piece 351 perpendicular to the paper width direction (corresponding to a direction parallel to the rotation shaft 811), and a sheet width direction from the lower end of the first support piece 351 to the side where the arms 301 to 304 are positioned. It consists of the 2nd support piece 352 extended along.

On the surface of the first support piece 351 on the side where the arms 301 to 304 are located, two pins 353 and 354 are erected at intervals in the paper transport direction.
A cylindrical first connecting portion 331 having a through hole in the sheet width direction is provided on one end side of the arm 303, and a first support portion 331 is rotatably supported on the pin 353 of the support plate 305 on the other end side. Two connecting portions 332 are provided.

A cylindrical first connecting portion 341 having a through hole in the paper width direction is provided on one end side of the arm 304, and a first support portion 341 that is rotatably supported by a pin 354 of the support plate 305 is provided on the other end side. Two connecting portions 342 are provided.
The first connecting portion 341 of the arm 304 includes a large-diameter portion 343 and a small-diameter portion 344 adjacent to the large-diameter portion 343, and is rotatably fitted on the rotation shaft 821 of the folding roller 82. Further, the first connecting portion 331 of the arm 303 is externally fitted to the small diameter portion 344 of the first connecting portion 341 of the arm 304.

As a result, the arm 303 and the arm 304 are rotatably supported by the rotation shaft 821 of the folding roller 82 and the pins 353 and 354 of the support plate 305.
Similarly, a cylindrical first connecting portion 311 having a through hole in the paper width direction is provided on one end side of the arm 301, and is rotatably supported on a pin 353 of the support plate 305 on the other end side. A second connecting portion 312 is provided.

A cylindrical first connecting portion 321 having a through hole in the paper width direction is provided on one end side of the arm 302, and a first support portion 321 rotatably supported by a pin 354 of the support plate 305 is provided on the other end side. Two connecting portions 322 are provided.
The first connecting portion 321 of the arm 302 is rotatably fitted to the rotation shaft 811 of the folding roller 81, and the first connecting portion 311 of the arm 301 is externally fitted to the small diameter portion 323 of the first connecting portion 321 of the arm 302. Has been.

Thereby, the arm 301 and the arm 302 are rotatably supported with respect to the rotating shaft 811 of the folding roller 81 and the pins 353 and 354 of the support plate 305.
When the rotation shaft 811 of the folding roller 81 and the rotation shaft 821 of the folding roller 82 are connected by the link mechanism 300 in this way, when the folding roller 82 is displaced in a direction away from the folding roller 81 (paper thickness direction), The support plate 305 is also displaced in the same direction.

In the present embodiment, both the folding rollers 81 and 82 have the same diameter, both the rotating shafts 811 and 821 have the same diameter, both the arms 301 and 303 have the same size, Both 302 and 304 have the same size.
Accordingly, even if the distance between the folding roller 81 and the folding roller 82 changes due to the thickness of the sheet bundle Sb interposed between the folding rollers 81 and 82 being different for each sheet bundle Sb, the pins of the support plate 305 are pinned. The positions in the sheet thickness direction of 353 and 354 are always maintained at the same position as the midpoint between the folding roller 81 and the folding roller 82.

FIG. 22 shows how the pins 353 and 354 of the support plate 305 are displaced when the sheet bundle Sb1 with n1 [sheets] and the sheet bundle Sb2 with n2 (> n1) [sheets] are folded. FIG. 22 is a front view of the link mechanism 300 as viewed from the direction indicated by the arrow K in FIG. 21. In FIG. 22, members unnecessary for the description of the link mechanism 300 are omitted.
As shown in the figure, since the thickness of the sheet bundle Sb2 is thicker than that of the sheet bundle Sb1, the distance in the sheet thickness direction (inter-roller distance) dp between the folding rollers 81 and 82 when folding the sheet bundle Sb1. In addition, the distance dq between the rollers when folding the sheet bundle Sb2 is larger, and the leading end Sa of the folded portion of the sheet bundle Sb2 corresponds to the difference in thickness than the leading end Sa of the folded portion of the sheet bundle Sb1. It is displaced to a position away from the folding roller 81 by the distance Lz.

The support plate 305 is displaced in the same direction by the same amount of displacement (= Lz) of the front end Sa of the folded portion of the sheet bundle Sb2 with respect to the front end Sa of the folded portion of the sheet bundle Sb1, so , 354 in the sheet thickness direction is equal to the intermediate position (midpoint) of the inter-roller distance regardless of the size of the inter-roller distance.
The position in the sheet thickness direction at the leading end Sa of the folded portion of the folded sheet bundle Sb is equal to the intermediate position in the sheet thickness direction of the sheet bundle Sb even if the thickness differs for each sheet bundle. The intermediate position in the sheet thickness direction is equal to the distance between the folding roller 81 and the folding roller 82 that sandwich the sheet bundle Sb, that is, the intermediate position of the distance between the rollers.

Therefore, when the link mechanism 300 is used, even if the thickness of each of the folded paper bundles Sb is different, the paper thickness between the leading end Sa of the folded portion of the paper bundle Sb and the pins 353 and 354 of the support plate 305. The position in the direction can be the same.
The positions in the sheet thickness direction of the folding end tip Sa of the sheet bundle Sb and the pins 353 and 354 of the support plate 305 are the same, indicating that the position of the heating unit 87 and the pins 353 and 354 of the support plate 305 in the sheet thickness direction. Are the same, even if the thickness of the sheet bundle Sb is different, the position Sa of the folding portion of the sheet bundle Sb and the heating unit 87 in the sheet thickness direction are the same, that is, the folding portion of the sheet bundle Sb. Thus, it is possible to maintain the state in which the heating portion 87 is in contact with the tip Sa of the plate.

Therefore, in the present embodiment, even if the thickness of each sheet bundle Sb is different, the support plate 305 that does not change the positional relationship in the sheet thickness direction with the front end Sa of the folded portion of the sheet bundle Sb is used as the positioning member of the heating unit 87. The heating unit 87 is prevented from shifting in the sheet thickness direction from the front end Sa of the folded part of the sheet bundle Sb. This will be specifically described with reference to FIG.
FIG. 23 is a cross-sectional view taken along line HH in FIG. 22 when the link mechanism 300 is cut. The heating unit 87 and the first heater support member 204a and the second heater support member 205 that support the heating unit 87 are shown in FIG. Shown together. The arms 302 and 304 are not shown.

  As shown in FIG. 23, when the heating unit 87 moves from the retracted position to the heating position, the lower end 204b of the first heater support member 204a comes into contact (engagement) with the second support piece 352 of the support plate 305, and By restricting the downward movement of the one heater support member 204a, the first heater support member 204a stops. By stopping the first heater support member 204a, the position of the heating unit 87 in the sheet thickness direction (heating position) with respect to the support plate 305 is determined.

  Since the position in the sheet thickness direction of the heating unit 87 is determined only by the relationship with the support plate 305, the position in the sheet thickness direction of the heating unit 87 positioned at the heating position and the pins 353 and 354 of the support plate 305 are the same position. If the length from the long hole 243 to the lower end 204b of the first heater support member 204a is set to an appropriate value in advance (so as to be positioned on one line 399), the sheet bundle Sb Even if the thicknesses are different, the heating unit 87 is not displaced in the sheet thickness direction from the leading end Sa of the folded portion of the sheet bundle Sb, and the leading end Sa can be locally heated.

As described above, in the second embodiment, by using the link mechanism 300, even if the thickness of each sheet bundle Sb is different, the intermediate position of the distance between the rollers in the folding rollers 81 and 82, that is, the sheet bundle folded in two. The heating unit 87 can be positioned at a position of the leading end Sa of the folded portion of Sb in the sheet thickness direction.
Therefore, the heating unit 87 can be reliably applied to the front end Sa of the folded portion of the sheet bundle Sb, and the power consumption associated with the low heat capacity can be further reduced by using the heating unit 87 having a smaller line width. Can be planned.

In the above description, the folding rollers 81 and 82 have the same diameter, the arms 301 and 303 have the same size, and the arms 302 and 304 have the same size. I can't.
Even if the thickness of each sheet bundle Sb changes, the diameters of the folding rollers 81 and 82 so that the position in the sheet thickness direction of the heating unit 87 is equal to the intermediate position of the distance between the rollers of the folding rollers 81 and 82. The lengths of the arms 301 to 304 may be determined.

  The present invention is not limited to the post-processing apparatus, and may be a method for heating a folded portion of a sheet. The method may be a program executed by a computer. Furthermore, the program according to the present invention can be read by a computer such as a magnetic disk such as a magnetic tape or a flexible disk, an optical recording medium such as a DVD-ROM, DVD-RAM, CD-ROM, CD-R, MO, or PD. It can be recorded on various recording media, and may be produced, transferred, etc. in the form of the recording medium, or in the form of a program, including wired and wireless networks including the Internet, broadcasting, telecommunications lines, In some cases, the data is transmitted and supplied via satellite communication or the like.

(Modification)
As described above, the present invention has been described based on the embodiment. However, the present invention is not limited to the above-described embodiment, and the following modifications may be considered.
(1) In the above embodiment, the configuration example in which the contact state between the heating unit 87 and the front end Sa of the folded portion of the sheet bundle Sb is maintained by the biasing force of the torsion spring 206 is not limited to this. A configuration using the magnetic force of the magnet can also be adopted.

FIG. 24 is a diagram illustrating a configuration example in which the contact state between the heating unit 87 and the leading end Sa of the folded portion of the sheet bundle Sb is maintained using the magnetic force of the magnet in addition to the biasing force of the torsion spring 206. . In the drawing, the second heater support member 205 and the torsion spring 206 that respectively support both ends of the heating section 87 in the sheet width direction are omitted, but they are arranged in the same manner as in the embodiment.
As shown in the figure, the heating unit 87 includes a heater 871, a substrate 872, and two magnets 873.

The heater 871 includes three heaters 87a, 87b, 87c that are long along the paper width direction, and are attached to the upstream surface of the substrate 872 in the paper conveyance direction at intervals in the paper width direction.
The heaters 87a, 87b, 87c are connected in series via lead wires 87d, 87e coated with insulation, and a driver 129 via a lead wire 875 connected to the heater 87a and a lead wire 876 connected to the heater 87c. (FIG. 9).

The substrate 872 is long along the paper width direction, and a recess 870 is provided in each of the portion between the heaters 87a and 87b and the portion between the heaters 87b and 87c on the upstream surface in the paper conveyance direction. Become.
The two magnets 873 each have an elongated plate shape along the paper width direction, and are attached so as to fit into two concave portions 870 provided on the substrate 872.

  The arrangement position of the magnet 873 (the position of the recess 870 in the sheet width direction) is a staple unit when the sheet bundle Sb before being folded is bound by the staple unit Sz by the staple unit 26 and then folded in two at the binding position. 26 is determined in advance so as to be a position corresponding to the binding position of the sheet bundle Sb in the sheet width direction. The staple needle Sz is made of a material that is attracted to the magnet 873 by the magnetic force of the magnet 873, here, iron.

  With the heaters 87a to 87c and the two magnets 873 attached to the substrate 872, the upstream surface (first surface) 901 of the heaters 87a to 87c and the upstream surface of the magnet 873 in the paper conveyance direction ( A step 877 is provided between the second surface 902 and the second surface 902 such that the second surface 902 is positioned downstream of the first surface 901 by a predetermined amount ds, here 0.5 mm. ing. The predetermined amount ds has a size corresponding to the diameter of the staple needle Sz, and the thicknesses of the heaters 87a to 87c and the magnet 873 are determined in advance so that a step 877 of the predetermined amount ds can be formed.

  In such a configuration, the sheet bundle Sb which is folded in two after being bound by the two staples Sz at a predetermined interval in the sheet width direction is conveyed toward the heating unit 87 with the folded portion at the top. When it comes, the staple Sa of each of the staples Sz protruding from the leading end Sa of the folded portion is in contact with the heaters 87a to 87c, and the step 877 between the opposing magnet 873 and the heater adjacent thereto. The magnet 873 is attracted to the magnet while being fitted in the space portion that is lowered by one step due to the above.

When the conveyed sheet bundle Sb is stopped, the heaters 87a to 87c are brought into contact with the front end Sa of the folded portion of the sheet bundle Sb by the urging force of the torsion spring 206 (not shown) as in the embodiment. The force of pulling the staple needle Sz by the magnetic force of the magnet 873 helps maintain this contact state.
Therefore, in parallel with the heating operation for the sheet bundle Sb, for example, when the sheet S to be subjected to post-processing such as stapling is conveyed to the post-processing apparatus 2, vibration generated in the apparatus due to the conveyance is performed. Is propagated to the sheet bundle Sb that is being heated, a magnetic force action is applied to bring the sheet bundle Sb closer to the heating section 87 by the magnet 873, so that the front end Sa of the sheet bundle Sb is moved from the heaters 87a to 87c. It is hard to occur that it will shift, and heating can be performed more stably.

In the above description, the configuration example in which the two magnets 873 are provided has been described. However, the number of the magnets 873 is not limited to two. It may be provided.
The predetermined amount ds is 0.5 [mm], but is not limited thereto. If the diameter of the staple needle Sz is dt, for example, it can be in the range of 0 <ds ≦ dt. Further, the surfaces of the heaters 87a to 87c and the magnet 873 can be flush without providing the step 877 (ds = 0).

Furthermore, when only the sheet bundle after stapling is to be heated, if the contact state between the heater and the leading end Sa of the folded portion of the sheet bundle Sb can be maintained only by the magnetic force of the magnet 873, the torsion spring 206 is set. The structure which does not provide can also be taken.
(2) In the above embodiment, a configuration example in which one long heater 871 is used along the paper width direction has been described. However, the present invention is not limited to this. For example, as shown in FIG. Two heaters 87a and 87b may be arranged at intervals in the paper width direction.

When this configuration is adopted, only the both end portions in the sheet width direction of the leading end Sa of the folded portion of the sheet bundle Sb are heated and the center portion in the sheet width direction is not heated, but the sheet bundle Sb on the free end side is not heated. By suppressing the bulging of both ends, the force to swell the central portion can be suppressed from both sides, and a certain effect can be obtained for preventing the bulging.
The number of heaters is not limited to two and may be two or more.

In addition, as shown in FIG. 26, the heating unit 87 can be moved along the paper width direction.
As shown in the figure, the heating unit 87 is provided with a short heater 879 on a substrate 878.
While the heater 879 of the heating unit 87 is in contact with the leading end Sa of the folded portion of the sheet bundle Sb, the heater 879 is energized while the heating unit 87 is moved from one end side to the other end side in the sheet width direction. The control which moves along is performed. As a result, the front end Sa of the folded portion of the sheet bundle Sb is heated over the entire width of the sheet.

If the heating unit 87 is moved along the paper width direction in this way, a short heater 879 can be used in the paper width direction, and the heater 879 can be downsized to further reduce the heat capacity of the heating unit 87. Low power consumption can be achieved.
In the figure, the moving mechanism of the heating unit 87 is omitted, but as the moving mechanism, for example, a support unit that supports the heating unit 87 slidably in the paper width direction, and the heating unit 87 is driven in the paper width direction. A drive unit such as a linear motion motor that applies force can be provided. The drive unit is controlled so that the heating unit 87 moves at a predetermined speed suitable for heating the sheet bundle Sb.

As the drive unit, for example, a drive mechanism in which a belt stretched around two or more pulleys is rotationally driven by a motor and the driving force of the belt is transmitted to the heating unit 87 may be employed.
(3) In the first embodiment, the configuration example in which the folding roller 82 is used as the positioning member for positioning the heating unit 87 at the heating position and the support plate 305 is used in the second embodiment has been described. It is not limited to.

If the sheet bundle Sb is a member that is displaced in the same direction as the displacement direction of the front end Sa of the folding portion that is displaced in the sheet thickness direction as the thickness of the sheet bundle Sb is increased, the member is used as a positioning member. Can do.
(4) In the above embodiment, the heating unit 87 is supported by the folding knife 201 so as to be movable in the sheet thickness direction, and the position of each of the folding knife 201 and the heating unit 87 is switched by one drive source. Although it demonstrated, it is not restricted to this, You may take the structure which provides a separate moving mechanism and a separate drive source with respect to each of the folding knife 201 and the heating part 87, respectively.

For example, a configuration in which the heating unit 87 is moved from the retracted position to the heating position by a driving force such as a motor can be considered. When this configuration is adopted, the amount of movement of the heating unit 87 in the sheet thickness direction is adjusted according to the amount of displacement in the sheet thickness direction of the leading end Sa of the folded portion of the sheet bundle Sb due to the difference in thickness of each sheet bundle Sb. Is done.
Specifically, first, the thickness of the sheet bundle Sb is determined in advance how far the front end Sa of the folded portion of the sheet bundle Sb is positioned in the sheet thickness direction with respect to the folding roller 81. Find it by experiment. During actual heating, (a) the thickness of the conveyed sheet bundle Sb is detected, and (b) the sheet corresponding to the detected thickness, that is, the sheet Sa to the folding roller 81 at the leading end Sa of the folding portion of the sheet bundle Sb. The position in the thickness direction is specified, and (c) the heating unit 87 can be moved to the specified position.

  The thickness of the sheet bundle Sb can be obtained from, for example, the thickness of the sheet S constituting the sheet bundle Sb and the number of sheets. If the thickness and the thickness of the paper S are associated with each type of the paper S (plain paper, cardboard, etc.) in advance, the thickness of the paper S of the type specified by the user can be acquired. Further, if the user inputs the thickness of the sheet bundle Sb from the operation unit or the like, the thickness of the sheet bundle Sb can be acquired from the input information.

Thus, when the structure which moves the heating part 87 independently is taken, a heating part interlock | cooperates with positioning members, such as the folding roller 82 which the position of a paper thickness direction changes according to the thickness for every paper bundle Sb as mentioned above. It is not necessary to employ a mechanism for displacing 87 in the same direction as the positioning member.
Accordingly, in the configuration of the folding roller pair 8a, one folding roller does not move in the contact / separation direction with respect to the other folding roller, that is, the configuration in which the movement of the rotating shafts 811 and 821 in the sheet thickness direction is restricted. Applicable.

In this configuration, for example, if one folding roller is made of metal and an elastic layer is provided around the axis of the other folding roller, a pressing force can be generated between the rollers by the elasticity.
Even when this configuration is adopted, if the thickness of each sheet bundle Sb is different, the amount of compression of the elastic layer of the other folding roller is different, so that one roller (made of metal) serving as a reference for the position in the sheet thickness direction is different. Thus, the position of the front end Sa of the folded portion of the sheet bundle Sb in the sheet thickness direction is displaced, but with the displacement, the heating unit 87 is moved independently so as to contact the front end Sa of the folded portion of the sheet bundle Sb. As a result, the tip Sa can be heated.

If it is determined in advance how much the leading end Sa of the folding portion is displaced in the sheet thickness direction with respect to the metal roller depending on the thickness of the sheet bundle Sb, the sheet thickness direction corresponding to the thickness of each sheet bundle Sb is determined. The heating unit 87 can be displaced to the position.
Further, when the folding knife 201 and the heating unit 87 are moved separately, for example, the positional relationship between the folding knife 201 and the heating unit 87 in the paper transport direction is opposite to that in the above embodiment, that is, the heating unit 87 is folded. It is also possible to adopt a configuration that is located downstream of the knife 201 in the paper conveyance direction. In addition, from the viewpoint of preventing an increase in the size of the apparatus, it is desirable that the moving direction of the folding knife 201 and the moving direction of the heating unit 87 be parallel as described above, but this is not necessarily limited thereto.

(5) In the above-described embodiment, the example in which the torsion spring 206 is used as an urging unit that applies an urging force in the direction opposite to the paper conveyance direction to the heating unit 87 has been described, but the present invention is not limited thereto. As long as it is a member that can apply an urging force in the direction opposite to the paper conveyance direction to the heating unit 87, it may be a spring of another shape or an elastic body other than the spring.
In addition, although the configuration example in which the heating unit 87 is supported by the first heater support member 204 so as to be movable along the sheet conveyance direction has been described, the present invention is not limited thereto. For example, if there is almost no variation in the transport distance until the stop of the sheet bundle Sb, a configuration in which the heating unit 87 is not moved in the sheet transport direction can be employed.

  (6) In the above-described embodiment, the configuration example in which the folding can be performed by selectively switching between the two-folding and the three-folding and the front end Sa of the folded portion of the sheet bundle Sb after the two-folding is heated has been described. Not limited. For example, it is possible to adopt a configuration in which the tip of the folded portion (the portion folded at the folding position β) of the sheet bundle after being folded in three is also heated. A heating unit different from the heating unit 87 is disposed downstream of the nip N2 of the second folding roller pair 8b in the sheet conveyance direction, and the other heating unit is arranged along the sheet thickness direction in the same manner as the heating unit 87. This can be realized by making it movable.

(7) In the above embodiment, the configuration example using the mechanism in which the folding roller 82 presses the folding roller 81 has been described. However, the configuration is not limited thereto.
For example, when the folding roller 81 presses the folding roller 82, that is, when the thickness of the sheet bundle Sb increases, the folding roller 81 can be displaced upward with respect to the folding roller 82.

In this configuration, the first heater support member 204 is provided with an engaging portion (corresponding to the extending portion 246) that engages with the rotation shaft 811 of the folding roller 81, and the folding roller 81 has a thickness of the sheet bundle Sb. Accordingly, the first heater support member 204 is configured to be displaced in the same direction.
Further, the example in the case where the image forming apparatus 1 and the post-processing apparatus 2 are separately configured has been described. However, the present invention is not limited to this. For example, the image forming apparatus 1 may include the post-processing apparatus 2 as a post-processing unit. it can.

Furthermore, the heating unit 87 as a heating member is not limited to the above-described configuration, and may be any member that is disposed on the downstream side in the paper transport direction with respect to the first folding roller pair 8a and can heat the leading end Sa of the paper folding unit. Further, the dimensions of the heating unit 87 and the predetermined amount P are not limited to the above values, and appropriate values are determined according to the apparatus configuration.
The contents of the above embodiment and the above modification may be combined.

  The present invention can be widely applied to post-processing apparatuses having a function of folding a sheet.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Post-processing apparatus 8a 1st folding roller pair 8b 2nd folding roller pair 28 Paper folding part 30 Control part 81,82,83 Folding roller 85 1st folding knife part 86 2nd folding knife part 87 Heating part 87a , 87b, 87c, 871, 879 Heater 98, 99 Conveying path 134 Second knife motor 137 Folding roller motor 201 Folding knife 201a Blade 204, 204a First heater support member 205 Second heater support member 206 Torsion spring 300 Link mechanism 301 , 302, 303, 304 Arm 305 Support plate 352 Second support piece 811, 821 Rotating shaft 830 Pitch ring 873, 874 Magnet 877 Step 901 Heater sheet conveyance direction upstream surface (first surface)
902 The upstream surface of the magnet in the paper transport direction (second surface)
N1, N2 Nipple of a pair of folding rollers P Movable range length of heating unit S Paper Sa Paper sheet tip Sb Paper bundle Sz Staple needle α, β Target folding position

Claims (10)

A post-processing device for folding a sheet by a pair of folding rollers,
A heating member disposed downstream of the pair of folding rollers in the sheet conveying direction;
A supporting means for supporting the heating member so as to be displaceable in the sheet thickness direction according to the thickness of the sheet so that the heating member is in contact with the tip of the folded portion of the folded sheet;
Of the first roller and the second roller constituting the pair of folding rollers, roller support means for supporting the second roller movably in the contact / separation direction with the first roller;
Roller urging means for urging the second roller in a direction approaching the first roller;
Equipped with a,
The support means is
A support member that supports the heating member and is movable along the sheet thickness direction;
A positioning member that engages with the support member and determines the position of the heating member in the sheet thickness direction;
The positioning member is
According to the thickness of the sheet, the second roller is displaced in the same direction as the second roller is displaced in a direction away from the biasing force against the biasing force. Post-processing device to do. The positioning member is
The post-processing apparatus according to claim 1 , wherein the post-processing apparatus is a rotation shaft of the second roller. The support means is
The support member is moved, the heating member is engaged with the positioning member and the heating member is positioned on the sheet conveyance path, and the heating member is not engaged with the positioning member. post-processing apparatus according to claim 1 or 2, characterized in that it comprises a switching means for switching to a retracted position retracted from the sheet conveying path. A third roller in contact with the second roller;
By pressing a portion of the sheet after being folded by the pair of folding rollers into a portion where the second roller and the third roller are in contact with each other, the second folding is performed on the sheet. A pushing member that performs the operation;
With
The post-processing apparatus according to claim 3 , wherein a moving direction of the support member from the heating position to the retracted position is parallel to a moving direction of the pushing member. The support member is
The push member is supported movably along the push direction,
The support means is
Urging means for applying an urging force in the same direction as the pushing direction to the support member;
The supporting member that moves together with the pushing member during the pushing operation of the pushing member engages with the positioning member, and the supporting member stops against the biasing force, so that the sheet of the heating member is stopped. The post-processing apparatus according to claim 4 , wherein a position in the thickness direction is determined. The pushing member is
Post-processing apparatus according to claim 4 or 5, characterized in that positioned in the sheet conveyance direction downstream side of the heating member. The pushing member and the heating member are:
Claim towards the side of the tip in contact with the sheet of the pushing member is characterized by having a relation that is located at a position closer to the third roller are in contact portion and the second roller than the heating member 4 to The post-processing apparatus according to any one of 6 . A stapler that binds a plurality of sheets stacked on each other before the sheet bundle is folded by the pair of folding rollers with a staple needle.
The heating member includes a heater and a magnet,
The staple needle is
Made of material that is attracted by the magnetic force of the magnet,
The heater is
Heating the tip of the folded portion of the sheet bundle,
The magnet
Wherein the heating member, the post-processing apparatus according to any one of claims 1 to 7, characterized in that it is disposed at a position corresponding to the stapling position in the sheet width direction to the sheet bundle by the stapler. Between the first surface on the upstream side in the sheet conveying direction of the heater and the second surface on the upstream side in the sheet conveying direction of the magnet, the second surface is located downstream in the sheet conveying direction with respect to the first surface. Steps are provided,
When the first surface of the heater is in contact with the leading end of the folded portion of the sheet bundle, the staples protruding from the leading end of the folded portion of the sheet are fitted into the space portion generated by the step. The post-processing apparatus according to claim 8 . An image forming unit for forming an image on a sheet;
A post-processing unit that performs post-processing on the sheet on which the image is formed;
An image forming apparatus comprising:
As the post-processing unit, an image forming apparatus comprising: a post-processing apparatus according to any one of claims 1-9.

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