JP6473981B2 - Sheet folding apparatus, image forming apparatus, and image forming system - Google Patents

Description

  The present invention relates to a sheet folding apparatus that performs a folding process on a sheet, an image forming apparatus including the sheet folding apparatus, and an image forming system.

  2. Description of the Related Art Conventionally, as a sheet folding apparatus, a folding portion (bending) formed on a sheet of paper or the like is sandwiched between folds of a pair of folding rollers, which are a pair of roller members, and conveyed to perform a folding process for forming a folded portion. It has been known.

  In the sheet folding apparatus described in Patent Document 1, an upstream-side conveyance roller pair and a downstream-side conveyance roller pair that are arranged along the sheet conveyance direction and hold a part of the sheet and apply conveyance force to the sheet are provided. It has been. Further, a folding roller pair that forms a folded portion on the sheet is provided by sandwiching a folded portion formed by bending the sheet between the upstream side conveying roller pair and the downstream side conveying roller pair. The upstream roller pair and the downstream roller pair hold a part of the sheet, and the downstream roller pair applies a conveying force to the upstream side in the sheet conveying direction, so that the upstream roller pair and the downstream roller pair are downstream. A folded portion is formed in the sheet portion between the pair of side rollers. The folded portion formed in this manner is guided and sandwiched between a pair of folding rollers, whereby a folded portion is formed on the sheet, and the sheet is subjected to folding processing.

  In the sheet folding apparatus, it is desired that various folding processes such as bi-folding, Z-folding, outer tri-folding, and inner tri-folding can be realized. Such various folding processes can be realized by changing the formation position of the folded portion of the sheet in the sheet conveying direction according to the type of folding process performed on the sheet. The formation position of the folded portion of the sheet in the sheet conveying direction can be changed by changing the protruding amount by which the leading end of the sheet protrudes from the downstream conveying roller pair and stopping the sheet according to the type of folding.

  Here, based on the detection timing of the sheet leading edge by the sheet leading edge detection sensor, the upstream conveying roller pair and the downstream are set such that the sheet leading edge protrudes from the downstream conveying roller pair by a predetermined projection amount and the sheet stops. It is conceivable to control the side conveying roller pair. For example, a sheet leading edge detection sensor is provided upstream of the upstream conveying roller pair in the sheet conveying direction, and after a predetermined time has elapsed from the detection timing of the sheet leading edge by the sheet leading edge detection sensor, the upstream conveying roller pair and the downstream conveying roller pair Stop the conveyance of the sheet.

  However, since the sheet passing between the upstream-side conveyance roller pair and the downstream-side conveyance roller pair is held only by the upstream-side conveyance roller pair, the sheet between the pair of rollers is affected by the rigidity and curl of the sheet. Variations in sheet behavior occur. When the sheet behavior varies in this way between the roller pairs, the sheet conveyance path until the sheet leading edge reaches the downstream conveying roller pair changes, and the timing when the sheet leading edge reaches the downstream conveying roller pair. Will shift. Therefore, if the conveyance of the sheet is stopped after a predetermined time has elapsed from the detection timing of the sheet leading edge by the sheet leading edge detection sensor, the amount of protrusion varies. As a result, the sheet cannot be stopped at an accurate position, and the formation position of the folded portion of the sheet in the sheet conveying direction varies, resulting in a problem that a satisfactory folding process cannot be performed.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a sheet folding device capable of suppressing variations in the formation position of the sheet folding portion in the sheet conveying direction, and an image forming apparatus including the sheet folding device. And an image forming system.

In order to achieve the above object, the invention of claim 1 is provided with a first conveying roller pair for nipping a sheet and conveying the sheet, and disposed downstream of the first conveying roller pair in the sheet conveying direction, a second pair of conveying rollers for conveying the sheet by sandwiching the sheet by sandwiching the sheet between the previous SL first conveying roller pair and the second pair of conveying rollers and a pair of folding rollers fold the sheet A sheet detection unit that detects a sheet downstream of the second conveying roller pair in the sheet conveying direction , and a sheet folded by the folding roller pair on the downstream side of the folding roller pair in the sheet conveying direction. And a second sheet detecting means for detecting a sheet on the downstream side in the sheet conveying direction of the third conveying roller pair, and one roller of the second conveying roller pair includes: , Positive It is rotatable and also serves as one of the pair of folding rollers, and the one roller forwardly rotates the one roller to convey the sheet downstream in the sheet conveying direction, and the sheet is after sending transportable first place quantitatively the sheet conveyance direction downstream side of the sheet detecting means, and reversing one of the rollers the back of the sheet to the sheet conveyance direction upstream side, folding is formed on the seat portion To the folding roller pair , and after the folded portion of the sheet has passed through the nip of the third conveying roller pair, the sheet is moved to the downstream side in the sheet conveying direction from the second sheet detecting means. A predetermined amount is conveyed and the sheet conveyance is stopped .

In the present invention, is provided with the sheet detection known means in the sheet conveying direction downstream side of the second conveying roller pair, after the sheet is interposed between the first conveying roller pair and the second conveying roller pair, sheet There is detected by the sheet detection intellectual means. Then, a predetermined amount of the sheet is conveyed from the position where the sheet detection unit detects the sheet, and the conveyance of the sheet is stopped. Thus, variations in the behavior of the sheet between the first conveying roller pair and the second conveying roller pair does not affect the stop position of the sheet. Therefore, the variation in the protrusion amount due to the variation in sheet behavior between the first conveyance roller pair and the second conveyance roller pair is suppressed, and the accuracy of the formation position of the folded portion of the sheet in the sheet conveyance direction is improved. Can be made.

  As described above, according to the present invention, there is an excellent effect that the formation position of the folded portion of the sheet in the sheet conveying direction can be suppressed.

FIG. 3 is a schematic diagram showing a main part of a folding processing apparatus according to Configuration Example 1; 1 is an explanatory diagram illustrating an example of an image forming system including a folding processing device according to an embodiment. 1 is a schematic configuration diagram of an image forming apparatus provided in an image forming system according to an embodiment. 1 is a schematic configuration diagram of a folding processing device provided in an image forming system according to an embodiment. (A)-(c) is explanatory drawing which respectively shows an example of the folding part formed by the folding process by a folding processing apparatus. (A)-(h) is explanatory drawing for demonstrating the general operation | movement at the time of performing Z folding process by a folding processing apparatus. (A)-(h) is explanatory drawing for demonstrating the general operation | movement at the time of performing an inner trifold process with a folding processing apparatus. (A)-(h) is explanatory drawing for demonstrating the general operation | movement at the time of an outer trifold process by a folding processing apparatus. 1 is a schematic configuration diagram of a sheet post-processing apparatus provided in the image forming system of the present embodiment. FIG. 6 is an explanatory diagram illustrating another example of an image forming system including a folding processing device according to an embodiment. The schematic diagram which shows an example of the principal part of the folding processing apparatus which concerns on a comparative example. Explanatory drawing in case the behavior of the sheet | seat after detecting a sheet | seat front-end | tip with an entrance sensor until it reaches a pressing roller is a straight state. Explanatory drawing when the behavior of the sheet | seat after detecting the front-end | tip of a sheet | seat by an entrance sensor until it reaches a pressing roller is curved. FIG. 6 is a schematic diagram showing a main part of a folding processing apparatus according to Configuration Example 2; FIG. 10 is a schematic diagram showing a main part of a folding processing apparatus according to Configuration Example 3;

  Hereinafter, an embodiment in which a folding processing apparatus which is a sheet conveying apparatus according to the present invention is applied to an image forming system will be described.

  FIG. 2 is an explanatory diagram illustrating an example of an image forming system including the folding processing device according to the present embodiment.

  The folding processing apparatus 1 according to this example is one of sheet post-processing apparatuses that performs post-processing on a sheet such as paper discharged from the image forming apparatus 2. In the image forming system of this example, a sheet post-processing that performs post-processing on a sheet on which a folding portion has been formed by the folding processing device 1 or on a sheet on which a folding portion has not been formed by the folding processing device 1 A device 3 is provided. Examples of the sheet post-processing device 3 include a punch punching device that punches holes in a sheet, a sheet binding device that binds a sheet bundle by a stapler, and a sorting discharge device that sorts and discharges image-formed sheets to a plurality of discharge trays. Etc.

  FIG. 3 is a schematic configuration diagram of the image forming apparatus 2 provided in the image forming system according to the embodiment. The image forming apparatus 2 includes a printer unit 100 that is a main body of the apparatus, a feeding unit 200 that is a feeding table, a scanner unit 300 that is mounted on the printer unit 100, and an automatic document feeder (ADF) that is mounted on the scanner unit 300. ). The image forming apparatus 2 also includes a control unit (not shown) that controls the operation of each device.

  The printer unit 100 includes an intermediate transfer belt 10 as an intermediate transfer member at the center thereof. The intermediate transfer belt 10 is wound around the first support roller 71, the second support roller 72, and the third support roller 73, and can move on the surface in the clockwise direction in the drawing. Then, a latent image carrier that carries one color toner image of yellow (Y), magenta (M), cyan (C), and black (K) on the surface so as to face the intermediate transfer belt 10. The four photosensitive drums 7Y, 7M, 7C, and 7K are provided.

  Around the photosensitive drums 7Y, 7M, 7C, and 7K, charging devices 4Y, 4M, 4C, and 4K that are charging means for uniformly charging the surfaces of the photosensitive drums 7Y, 7M, 7C, and 7K, and toner images Developing devices 5Y, 5M, 5C, and 5K, which are developing means for forming the. Further, the cleaning devices 6Y, 6M, 6C, and 6K for removing the toner remaining on the surface of the photosensitive drums 7Y, 7M, 7C, and 7K after the primary transfer, and the lubricant for applying a lubricant to the surface of the photosensitive drum. Coating devices 8Y, M, C, and K are also provided.

  The toner image forming unit includes the photosensitive drums 7Y, 7M, 7C, 7K, developing devices 5Y, M, C, and K, charging devices 4Y, M, C, and K, and cleaning devices 6Y, M, C, and K. The image forming devices 19Y, 19M, 19C, and 19K are configured. Further, the tandem image forming unit 60 is configured by arranging the four image forming devices 19Y, 19M, 19C, and 19K side by side.

  A belt cleaning device 17 that removes residual toner remaining on the intermediate transfer belt 10 after the toner image is transferred onto the sheet P as a recording medium so as to face the third support roller 73 with the intermediate transfer belt 10 interposed therebetween. It has. The printer unit 100 includes an exposure device 61 above the tandem image forming unit 60.

  Primary transfer rollers 9Y, 9M, 9C, and 9K are provided at positions on the inner side of the intermediate transfer belt 10 that face the photosensitive drums 7Y, 7M, 7C, and 7K with the intermediate transfer belt 10 therebetween. The primary transfer rollers 9Y, 9M, 9C, and 9K are provided so as to be pressed against the photosensitive drums 7Y, 7M, 7C, and 7K with the intermediate transfer belt 10 interposed therebetween to form a primary transfer portion.

  On the other hand, a secondary transfer device 69 is provided on the opposite side of the intermediate transfer belt 10 from the tandem image forming unit 60. The secondary transfer device 69 is configured such that a secondary transfer belt 64 is stretched between a secondary transfer roller 62 and a secondary transfer belt stretching roller 63. In the secondary transfer device 69, the secondary transfer belt 64 is pressed against the third support roller 73 via the intermediate transfer belt 10 at a position supported by the secondary transfer roller 62. A secondary transfer nip portion as a secondary transfer portion is formed between the secondary transfer belt 64 and the intermediate transfer belt 10.

  A fixing device 65 for fixing the transfer image on the sheet P is provided on the left side of the secondary transfer device 69 in the drawing. The fixing device 65 is configured by pressing a pressure roller 67 against a fixing belt 66 that is an endless belt. Further, the above-described secondary transfer device is also provided with a sheet conveyance function for conveying the sheet P that has received the transfer of the toner image at the secondary transfer nip portion to the fixing device 65. Note that a transfer roller or a non-contact charging charger may be disposed as the secondary transfer device. In such a case, it is difficult to provide this sheet conveying function together.

  Under the secondary transfer device and the fixing device 65, a sheet reversing device 68 for reversing the sheet P in order to record images on both sides of the sheet P is provided in parallel with the tandem image forming unit 60 described above. As a result, after the image is fixed on one side of the sheet P, the path of the sheet P is switched to the sheet reversing device side by the switching claw, and the sheet P is reversed and conveyed to the secondary transfer nip portion again to transfer the toner image. Thereafter, it can be discharged to the folding processing apparatus 1.

  The scanner unit 300 reads the image information of the document placed on the contact glass 32 by the reading sensor 36 and sends the read image information to the control unit.

  Based on the image information received from the scanner unit 300, a control unit (not shown) controls a laser (not shown) or an LED (not shown) disposed in the exposure device 61 of the printer unit 100 and lasers it toward the photosensitive drum 7. The writing light L is irradiated. By this irradiation, an electrostatic latent image is formed on the surface of the photosensitive drum 7, and this latent image is developed into a toner image through a predetermined development process.

  The feeding unit 200 includes a multi-stage feeding cassette 44 provided in the paper bank 43, a feeding roller 42 that feeds the sheet P from the feeding cassette, a separation roller 45 that separates the fed sheet P and sends it to the feeding path 46, and a feeding roller 46. A conveyance roller 47 that conveys the sheet P is provided in the feeding path 48.

  In the image forming apparatus 2 of the present embodiment, manual feeding is possible in addition to the feeding unit 200, and the manual feed tray 51 for manual feeding and the sheet P on the manual tray 51 are directed toward the manual feeding path 53. A separation roller 52 for separating the sheets one by one is also provided on the side of the apparatus.

  The registration roller 49 discharges only one sheet P placed on the feeding cassette 44 or the manual feed tray 51, and is positioned between the intermediate transfer belt 10 as an intermediate transfer member and the secondary transfer device. Send to the next transfer nip.

  In the image forming apparatus 2 of the present embodiment, when copying a color image, a document is set on the document table 30 of the document transport unit 400. Alternatively, the original conveying unit 400 is opened, an original is set on the contact glass 32 of the scanner unit 300, and the original conveying unit 400 is closed to hold the original.

  When a start switch (not shown) is pressed, when the document is set on the document transport unit 400, the document is transported onto the contact glass 32, and then the scanner unit 300 is driven to drive the first travel body 33 and the second travel. Travel through the body 34. On the other hand, when the document is set on the contact glass 32, the scanner unit 300 is immediately driven to travel the first traveling body 33 and the second traveling body 34. Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34 and reflects by the mirror of the second traveling body 34 and passes through the imaging lens 35. The image information of the original is read by putting in the reading sensor 36.

  The surfaces of the photosensitive drums 7Y, 7M, 7C, and 7K are uniformly charged by the charging devices 4Y, 4M, 4C, and 4K, and the image information read by the scanner unit 300 is color-separated. In addition, laser writing is performed on the photosensitive drums 7Y, 7M, 7C, and 7K. Thereby, an electrostatic latent image is formed on the surface of the photosensitive drums 7Y, 7M, 7C, and 7K.

  As an example, description will be made by performing image formation of Y (yellow). The electrostatic latent image formed on the surface of the photoconductor drum 7C is developed by the developing device 5Y in accordance with the Y toner to form a single color toner image. Similarly, a monochrome toner image is formed on the photosensitive drum 7 in the same manner in each of the image forming devices 19M, C, and K in the order of M (magenta), C (cyan), and K (black). In this manner, a toner image is formed on each photosensitive drum 7 and one of the four feeding rollers is operated to feed the sheet P having a size corresponding to the image information.

  At the same time, one of the first support roller 71, the second support roller 72, or the third support roller 73 is rotationally driven by a drive motor (not shown), and the other two support rollers are driven to rotate. The intermediate transfer belt 10 is rotated and conveyed. Then, along with the conveyance of the intermediate transfer belt 10, monochromatic toner images on the photosensitive drums 7 Y, M, C, and K are sequentially transferred to form a composite color image on the intermediate transfer belt 10.

  On the other hand, in the feeding unit 200, one of the feeding rollers 42 is selectively rotated, the sheet P is fed out from one of the feeding cassettes 44, separated one by one by the separation roller 45, and put into the feeding path 46, and the conveying roller The sheet P is brought into contact with the registration roller 49 and stopped.

  Alternatively, the feeding roller 50 is rotated to feed out the sheet P on the manual feed tray 51, separated one by one by the separation roller 52, put into the manual feed path 53, and abutted against the registration roller 49 and stopped.

  When using the sheet P on the manual feed tray 51, the feeding roller 50 is rotated to feed out the sheet P on the manual feed tray 51, separated one by one by the separation roller 52, and put into the manual feed path 53. Similarly, it abuts against the registration roller 49 and stops.

  Then, the registration roller 49 is rotated in time with the composite color image on the intermediate transfer belt 10, and the sheet P is fed into the secondary transfer nip portion where the intermediate transfer belt 10 and the secondary transfer roller 62 are in contact with each other. . Then, the composite color image is secondarily transferred from the intermediate transfer belt 10 onto the sheet P due to the influence of the transfer electric field and contact pressure formed at the secondary transfer nip, and the color image is transferred onto the sheet P. Record.

  The sheet P after receiving the color image transfer at the secondary transfer nip is sent to the fixing device 65 by the secondary transfer belt 64 of the secondary transfer device 69, and the pressure roller 67 and the fixing belt are fixed by the fixing device 65. The color image is fixed by applying pressure and heat. Thereafter, the paper is discharged to the folding processing device 1 by the discharge roller 56.

  Further, after fixing the color image, the sheet P on which images are formed on both sides is switched by the switching claw 55 and conveyed to the sheet reversing device 68 where it is reversed and guided again to the secondary transfer nip portion. After the image is also recorded, the image is discharged to the folding processing apparatus 1 by the discharge roller 56.

  On the other hand, the residual toner remaining on the surface of the intermediate transfer belt 10 after the color image is transferred to the sheet P at the secondary transfer nip portion is removed by the belt cleaning device 17, so that the tandem image forming unit 60 can form an image again. Prepare.

  FIG. 4 is a schematic configuration diagram of the folding processing apparatus 1 provided in the image forming system according to the embodiment.

  The folding processing apparatus 1 of the present embodiment includes a through conveyance path W1 for conveying the sheet P to the subsequent sheet post-processing apparatus 3 without folding the sheet P discharged from the image forming apparatus 2. Further, a branch conveyance path W2 is provided which is branched from the through conveyance path W1 and folds the sheet P discharged from the image forming apparatus 2 and conveys the sheet P to the subsequent sheet post-processing apparatus 3. .

  On the inlet side (the right side in the drawing) of the through conveyance path W1 that receives the sheet P discharged from the image forming apparatus 2, an inlet roller pair 11 as a first sheet conveyance unit is disposed. The inlet roller pair 11 includes a pressing roller 11a that is a rotating member and a driving roller 11b that is a counter member. The driving roller 11b is rotationally driven by a driving force of an inlet motor 11m that is a driving source.

  Further, on the exit side (the left side in the figure) of the through conveyance path W 1, a first folding roller 12, a first forward / reverse roller 13 disposed in contact with the first folding roller 12, and a first forward / reverse roller 13 A pressing roller 14 disposed in contact therewith is provided. By passing through the nip between the first folding roller 12 and the first forward / reverse roller 13, the sheet P can move from the through conveyance path W1 to the branch conveyance path W2. Further, by passing through the nip between the first forward / reverse rotation roller 13 and the pressing roller 14, the sheet P can be conveyed to the subsequent sheet post-processing apparatus 3 via the through conveyance path W1.

  Further, in the present embodiment, a second folding roller 15 disposed in contact with the first forward / reverse rotation roller 13 is provided on the exit side of the branch conveyance path W2. Further, in this branch conveyance path W2, across the nip between the first folding roller 12 and the first forward / reverse rotation roller 13 into which the sheet P from the through conveyance path W1 enters, on the opposite side of the second folding roller 15, A second forward / reverse roller pair 16 is provided. The second forward / reverse roller pair 16 includes a pressing roller 16a as a rotating member and a driving roller 16b as an opposing member. The driving roller 16b is driven by a driving force of a second forward / reverse motor 16m as a driving source. Rotating drive.

  The first forward / reverse roller 13 can be driven to rotate in a forward / reverse manner by the driving force of the first forward / reverse motor 13m capable of forward / reverse rotation. The first folding roller 12, the pressing roller 14, and the second folding roller 15 that are disposed in contact with the first forward / reverse roller 13 are all driven rollers that are driven to rotate as the first forward / reverse roller 13 rotates. It is.

  Further, the driving roller 16b constituting the second forward / reverse roller pair 16 can be rotationally driven so as to be able to rotate forward and backward by the driving force of the second forward / reverse rotation motor 16m capable of forward / reverse rotation. The pressing roller 16a constituting the second forward / reverse roller pair 16 is a driven roller that is driven to rotate as the driving roller 16b rotates.

  In the present embodiment, the roller shafts of all the driven rollers are urged by pressure springs 11s, 12s, 14s, 15s, and 16s as urging means. Is to be formed.

  Further, in the present embodiment, an inlet sensor 21 as a sheet edge detection unit that detects the edge of the sheet P is provided on the upstream side in the sheet conveyance direction of the inlet roller pair 11 (through conveyance path W1 inlet side). ing. When the leading edge of the sheet P conveyed from the image forming apparatus 2 reaches the detection area, the inlet sensor 21 outputs a leading edge detection signal indicating that fact to a control unit (not shown). As such an inlet sensor 21, a known sensor can be widely used.

  Further, in the present embodiment, the leading edge of the sheet P is disposed on the downstream side in the sheet conveyance direction (the exit side of the through conveyance path W1) of the second sheet conveyance unit including the first forward / reverse rotation roller 13 and the pressing roller 14. A sheet detection sensor 22 is provided as a sheet leading edge detection means for detecting the above. When the leading edge of the sheet P conveyed through the through conveyance path W1 reaches the detection area, the sheet detection sensor 22 outputs a leading edge detection signal indicating that fact to a control unit (not shown). As such a sheet detection sensor 22, a well-known sensor can be widely used as in the case of the inlet sensor 21 described above.

  In the present embodiment, a sheet detection sensor 26 that detects the leading edge of the sheet P is provided on the downstream side in the sheet conveyance direction of the second forward / reverse rotation roller pair 16 (on the opposite side to the exit side of the branch conveyance path W2). ing. When the leading edge of the sheet P sent from the through conveyance path W1 to the branch conveyance path W2 reaches the detection area, the sheet detection sensor 26 outputs a leading edge detection signal indicating that fact to a control unit (not shown). As such a sheet detection sensor 26, a well-known sensor can be widely used like the entrance sensor 21 and the sheet detection sensor 22 described above.

  In the present embodiment, the first forward / reverse roller 13 and the pressing roller 14 constitute a second sheet conveying means, and the first folding roller 12 and the first forward / reverse roller 13 constitute a folding part forming means. Yes. In the present embodiment, the first forward / reverse rotation roller 13 and the second folding roller 15 also constitute a folding portion forming means.

  As the second sheet conveying unit, a configuration of an adhesive roller or a suction belt may be adopted instead of the configuration of such a roller pair. In the present embodiment, the first forward / reverse roller 13 constituting the second sheet conveying unit and the first forward / reverse roller 13 and the second folding roller 15 constituting the folding part forming unit are common rollers. However, the present invention is not limited to this, and the second sheet conveying unit and the folded portion forming unit may be configured separately and independently using separate rollers.

  Next, the flow and operation of folding processing for forming a folding portion on the sheet P by the folding processing apparatus 1 will be described.

  FIGS. 5A to 5C are explanatory views respectively showing examples of folding portions formed by folding processing by the folding processing apparatus 1 of the present embodiment.

  The folding processing apparatus 1 according to the present embodiment can perform a Z-folding process in which two outward folding portions are formed on the sheet P to form a Z-fold as shown in FIG. Further, the folding processing apparatus 1 according to the present embodiment forms an inner trifold by forming two inwardly folded portions of the sheet P into approximately three equal parts and folding the sheet P into an inner trifold as shown in FIG. Processing can be performed. Further, the folding processing apparatus 1 according to the present embodiment forms an outer tri-fold by forming two outer folding portions with respect to the sheet P approximately in three equal parts and forming an outer tri-fold as shown in FIG. Processing can be performed.

  FIGS. 6A to 6H are explanatory diagrams for explaining a general operation when the folding processing device 1 performs the Z-folding process.

  First, the entrance sensor 21 detects the leading edge of the sheet P that is conveyed with a conveying force applied from a discharge roller (not shown) on the image forming apparatus 2 side. As a result, the control unit (not shown) that has received the tip detection signal output from the inlet sensor 21 controls the inlet motor 11m to start rotation of the inlet roller pair 11 (FIGS. 6A and 6B). )). After that, when the leading edge of the sheet P enters the nip of the entrance roller pair 11, the transport force is applied from the entrance roller pair 11 and the sheet P is transported through the through-conveying path W1 toward the exit side.

  The leading edge of the sheet P conveyed through the through conveyance path W1 enters the nip between the first forward / reverse rotation roller 13 and the pressing roller 14, and is detected by the sheet detection sensor 22 after passing through the nip. The control unit that has received the leading edge detection signal from the sheet detection sensor 22 that has detected this performs the following control. That is, when the leading edge of the sheet P protrudes by a predetermined protrusion amount from the nip position between the first forward / reverse rotation roller 13 and the pressing roller 14 (FIG. 6C), the first forward / reverse rotation motor 13m is controlled. Then, the rotation of the first forward / reverse roller 13 is stopped. At the same time, the inlet motor 11m is controlled to stop the rotation of the driving roller 11b of the inlet roller pair 11.

  The amount of protrusion at this time is appropriately determined depending on the length of the sheet P in the sheet conveyance direction and the content of the folding process (folding method, etc.). The protrusion amount of the leading edge of the sheet P can be grasped from, for example, the reception timing of the leading edge detection signal output from the sheet detection sensor 22 and the rotation amount of the pressing roller 14.

  Thereafter, the first forward / reverse rotation motor 13m is controlled to start the reverse rotation of the first forward / reverse rotation roller 13 in the direction to return the sheet P to the entrance side of the through conveyance path W1, and to start the rotation of the entrance roller pair 11. . As a result, the sheet portion between the entrance roller pair 11 and the first forward / reverse roller 13 is bent (FIG. 6D). Then, the bent portion (folded portion) enters the nip between the first folding roller 12 and the first forward / reverse roller 13, whereby a first folded portion is formed at the folded portion. The first folding portion that has passed through the nip between the first folding roller 12 and the first forward / reverse roller 13 enters the branch conveyance path W2 (FIG. 6E), and passes through the branch conveyance path W2 in the second forward / reverse direction. It is conveyed toward the roller pair 16.

  The first folding portion of the sheet P enters the nip of the second forward / reverse roller pair 16, and is detected by the sheet detection sensor 26 after passing through the nip. The control unit that has received the leading edge detection signal from the sheet detection sensor 26 that has detected this performs the following control. That is, when the first folding portion of the sheet P protrudes from the nip position of the second forward / reverse roller pair 16 by a predetermined protrusion amount (FIG. 6 (f)), the first forward / reverse motor 13m is controlled. The rotation of the first forward / reverse roller 13 is stopped. At the same time, the rotation of the second forward / reverse roller pair 16 and the inlet roller pair 11 is stopped. The amount of protrusion at this time is also appropriately determined depending on the length of the sheet P in the sheet conveyance direction and the content (folding method, etc.) of folding processing. The amount of protrusion of the first folding portion of the sheet P can be grasped from, for example, the reception timing of the leading edge detection signal output from the sheet detection sensor 26 and the rotation amount of the second forward / reverse rotation roller pair 16.

  Thereafter, the second forward / reverse rotation motor 16m is controlled to control the second forward / reverse rotation motor 16m, and the reverse rotation of the second forward / reverse rotation roller pair 16 is started in the direction in which the sheet P is directed toward the exit side of the branch conveyance path W2. At the same time, the reverse rotation of the first forward / reverse rotation roller 13 and the rotation of the inlet roller pair 11 are resumed. As a result, a bend is formed in the sheet portion between the first forward / reverse rotation roller 13 and the second forward / reverse rotation roller pair 16 (FIG. 6G). The bent portion (folded portion) enters the nip between the first forward / reverse rotation roller 13 and the second folding roller 15, whereby a second folded portion is formed at the folded portion.

  The second folding portion that has passed through the nip between the first forward / reverse rotation roller 13 and the second folding roller 15 is conveyed toward the exit side of the branch conveyance path W2 (FIG. 6 (h)). Then, the sheet P on which the two folded portions are formed in this way is conveyed to the subsequent sheet post-processing apparatus 3 under the conveyance force from the first forward / reverse rotation roller 13.

  FIGS. 7A to 7H are explanatory diagrams for explaining a general operation when the folding processing device 1 performs the inner tri-folding process.

  FIGS. 8A to 8H are explanatory diagrams for explaining a general operation when the folding processing device 1 performs the outer trifold process.

  The flow of operation of both the inner trifold process and the outer trifold process is the same as that of the Z-fold process described above, but the protrusion amount and the protrusion amount are different. Therefore, the timing for starting the reverse rotation of the first forward / reverse rotation roller 13 and the second forward / reverse rotation roller pair 16 differs between the Z-folding process, the inner trifolding process, and the outer trifolding process.

  FIG. 9 is a schematic configuration diagram of the sheet post-processing apparatus 3 provided in the image forming system of the present embodiment.

  The sheet post-processing apparatus 3 includes an inlet sensor 302, an inlet roller pair 303, a branch claw 304, a discharge roller pair 305, a binding tool 310, a conveyance path 340, a branch path 341, and the like.

  The entrance sensor 302 detects the front end, the rear end, and the presence / absence of the sheet P carried from the folding processing apparatus 1 to the sheet post-processing apparatus 3.

  The entrance roller pair 303 is located at the entrance of the sheet post-processing apparatus 3 and has a function of carrying the sheet P into the sheet post-processing apparatus 3. By using the roller nip of the entrance roller pair 303, it is possible to correct the abutting skew of the sheet P. The inlet roller pair 303 is driven by a controllable drive source (not shown). This drive source is controlled by a control unit (not shown), and thereby the rotational driving and stopping of the inlet roller pair 303 by the drive source and the conveyance amount of the sheet P by the inlet roller pair 303 are controlled. The control unit may be provided in the image forming apparatus 2.

  The conveyance path 340 is a normal path for conveying and discharging the received sheet P. The branch path 341 is a conveyance path that is provided to overlap and align the sheets P and is carried in from the rear end side by the switchback of the sheets P.

  The branch claw 304 is a claw member that is rotatably provided to switch the conveyance path in order to guide the rear end of the sheet P from the conveyance path 340 to the branch path 341. Further, the branching claw 304 is configured to be able to press the sheet P against the conveyance surface of the branching path 341, and the sheet P can be fixed by this pressing.

  The binding tool 310 is a tool for binding the sheet bundle aligned in the branch path 341 without using a metal needle. In the present embodiment, the binding tool 310 that deforms the sheet P and entangles the fibers by sandwiching the sheet bundle with a pair of tooth molds having irregularities on the surface is used. In addition, the sheet bundle is subjected to U-shaped cutting and bending, and at the same time, a slit is opened in the vicinity of the bending source so that the cut and bent leading end portion cannot be unwound through the slit without using a metal needle. A binding tool that binds the bundle may be used. Note that the binding means for binding the sheet bundle is not limited to the binding tool of the present embodiment, and may have a function of binding like a widely known binding tool.

  The discharge roller pair 305 is located at the exit of the sheet post-processing device 3 and has a function of discharging the sheet bundle bound by the binding tool 310 to a discharge tray (not shown). Further, the discharge roller pair 305 is driven by a controllable drive source (not shown). The driving source is controlled by the control unit, and thereby the rotational driving and stopping of the discharge roller pair 305 by the drive source and the conveyance amount of the sheet P by the discharge roller pair 305 are controlled.

  FIG. 10 is an explanatory diagram illustrating another example of the image forming system including the folding processing device according to the present embodiment.

  The folding processing apparatus 1 according to this example forms a folded portion on the sheet P inside the image forming apparatus 2. Even in the image forming system of this example, a sheet that performs post-processing on the sheet P on which the folding portion is formed by the folding processing device 1 or on the sheet P on which the folding portion is not formed by the folding processing device 1. A post-processing device 3 is provided.

  FIG. 10 is a schematic configuration diagram of the image forming apparatus 2 in which the folding processing device 1 is disposed in the cylinder. In FIG. 1, the image forming apparatus 2 includes an image forming apparatus main body 101, a folding processing apparatus 1, and an image reading apparatus 500.

  The image forming apparatus main body 101 is an indirect transfer type tandem color image forming apparatus. In the figure, an image forming unit 110 in which four color image forming stations 111Y, 111C, 111M, and 111K are arranged at a substantially central portion. An optical writing device 18 is provided adjacent to the lower side of the image forming unit 110. A feeding unit 120 is provided below the optical writing device 18. Further, a feeding conveyance path (vertical conveyance path) 130 for conveying the sheet P fed from the feeding unit 120 to the secondary transfer unit 140 and the fixing device 150 is provided. Further, the discharge conveyance path 160 for conveying the sheet P on which the image is fixed by the fixing device 150 to the folding processing device 1 side, or both sides for reversing the sheet P on which the image is formed on one side and forming an image on the other side. A conveyance path 170 is provided.

  The image forming unit 110 includes photosensitive drums 20Y, C, M, and K for the respective colors of the image forming stations 111Y, 111C, 111M, and 111K. Along the outer periphery of the photosensitive drum 20Y, C, M, K, charging devices 80Y, C, M, K, developing devices 70Y, C, M, K, cleaning units 40Y, C, M, K, and There is no static elimination unit. In addition, the intermediate transfer belt 112 for intermediate transfer of images formed on the photosensitive drums 20Y, C, M, and K by primary transfer rollers 74Y, 74C, 74M, and K, and the respective colors on the photosensitive drums 20Y, 20C, 20M, and 20K. And an optical writing device 18 for writing an image every time.

  The optical writing device 18 is disposed below the image forming station 111, and the intermediate transfer belt 112 is disposed above the image forming station 111. Above the image forming unit 110, toner storage containers 116Y, 116C, 116M, and 116K that store toner for replenishing the developing devices 70Y, 70C, 70M, and 70K are disposed so as to be replaceable.

  The intermediate transfer belt 112 is rotatably supported by a plurality of support rollers. The support roller 114, which is one of the plurality of support rollers, faces the secondary transfer roller 115 through the intermediate transfer belt 112 in the secondary transfer unit 140, and the image on the intermediate transfer belt 112 is secondary to the sheet P. Can be transcribed.

  The image forming process of the indirect transfer tandem color image forming apparatus is well known and is not directly related to the gist of the present invention, and thus detailed description thereof is omitted.

  The feeding unit 120 includes a feeding tray 121, a pickup roller 122, and a feeding / conveying roller 123, and sends the sheet P picked up from the feeding tray 121 upward along the feeding / conveying path 130.

  The fed sheet P has the image transferred by the secondary transfer unit 140 and is sent to the fixing device 150. The fixing device 150 includes a fixing roller 150a and a pressure roller 150b. In the process where the sheet P passes through the nip between the both, heating and pressing are performed, and the toner is fixed to the sheet P.

  A discharge conveyance path 160 and a double-side conveyance path 170 are provided downstream of the fixing device 150, both of which are branched in two directions by a branching claw 161 and conveyed to the folding processing apparatus 1 side. The transport path is selected depending on the case of transport.

  A branch conveyance roller 162 is provided in the immediate vicinity of the branch claw 161 on the upstream side in the sheet conveyance direction, and applies a conveyance force to the sheet P.

  The folding processing apparatus 1 is arranged inside the image forming apparatus main body 101, performs a folding process on the image-formed sheet P conveyed from the image forming apparatus main body 101, and discharges it to the sheet post-processing apparatus 3 shown in FIG. Is.

  The image reading device 500 is a known device that optically scans a document set on a contact glass 501 and reads an image on a document surface. Since the configuration and function of the image reading apparatus 500 itself are known and are not directly related to the gist of the present invention, detailed description thereof is omitted.

  The image forming apparatus main body 101 configured as described above generates image data used for writing based on document data read from the image reading apparatus 500 or print data transferred from an external PC or the like. Then, based on the image data, optical writing is performed from the optical writing device 18 to each of the photosensitive drums 20Y, 20C, 20M, and 20K. The images formed for the respective colors at the respective image forming stations 111Y, 111C, 111M, and 111K are sequentially transferred to the intermediate transfer belt 112, and a color image in which four color images are superimposed on the intermediate transfer belt 112 is formed. The

  On the other hand, the sheet P is fed from the feeding tray 121 according to the image formation. The sheet P is temporarily stopped at a registration roller position (not shown) immediately before the secondary transfer unit 140, sent in time with the leading edge of the image on the intermediate transfer belt 112, secondarily transferred by the secondary transfer unit 140, and fixed. It is sent to the device 150.

  The sheet P on which the image is fixed by the fixing device 150 is conveyed to the discharge conveyance path 160 side by the switching operation of the branching claw 161 in the case of single-sided printing or after double-sided printing of double-sided printing. Is conveyed to the double-sided conveyance path 170 side.

  The sheet P conveyed to the double-sided conveyance path 170 is reversed and then sent again to the secondary transfer unit 140 to form an image on the other side, and then returned to the discharge conveyance path 160 side.

  The sheet P transported to the discharge transport path 160 side is transported to the folding processing device 1 and is subjected to folding processing by the folding processing device 1 or discharged to the sheet post-processing device 3 without processing.

  Note that the sheet post-processing apparatus 3 shown in FIG. 9 is used as the sheet post-processing apparatus 3 included in the image forming system, and the description thereof is omitted.

[Configuration example 1]
FIG. 1 is a schematic diagram showing a main part of a folding processing apparatus 1 according to Configuration Example 1. As shown in FIG.
In FIG. 1, the sheet P sent from the image forming apparatus passes through the inlet roller pair 11 and reaches the pressing roller 14. The pressing roller 14 is stopped at a position where it passes through the pressing roller 14 and the leading end of the sheet protrudes from the pressing roller 14 by a protruding amount which is a predetermined amount calculated from the folding position, and then reversely rotated. If the direction toward the downstream side is the forward direction, the inlet roller pair 11 rotates in the forward direction and the pressing roller 14 rotates in the reverse direction, so that the sheet P is bent between the inlet roller pair 11 and the pressing roller 14. Can be made. Folding can be performed by sandwiching the bending between the first forward / reverse rotation roller 13 and the first folding roller 12.

  Here, the amount of protrusion calculated from the folding position is determined in consideration of the position where the sheet P is to be folded, a value obtained from the geometrical relationship of the roller configuration, and an adjustment value obtained experimentally. Value. The adjustment value is obtained by experimentally quantifying the offset amount of the folding position due to the difference in the thickness of the sheet P, the type of the sheet P, and the like.

  In this way, the folding position is determined by the amount of protrusion from the pressing roller 14, so that if the amount of protrusion varies, the folding position also varies.

  FIG. 11 is a schematic diagram illustrating an example of a main part of a folding processing apparatus according to a comparative example. In the folding processing apparatus according to this comparative example, the sheet detection sensor 22 provided downstream of the pressing roller 14 in the sheet conveying direction in the folding processing apparatus according to the configuration example 1 illustrated in FIG.

  In the folding processing apparatus according to the comparative example shown in FIG. 11, a trigger that serves as a reference for stopping the sheet P or reversing the pressing roller 14 is the sheet leading edge detection by the inlet sensor 21. For example, after the entrance sensor 21 detects the sheet leading edge, the sheet P is stopped after X1 [ms], or after the entrance sensor 21 detects the sheet leading edge, the sheet P is stopped after X2 [mm] conveyance. become. However, in this case, the stop position of the sheet P varies depending on the conveyance behavior of the sheet P after the leading edge of the sheet is detected by the inlet sensor 21 until reaching the pressing roller 14 for the reason described later.

  That is, when the sheet P is in a straight state as shown in FIG. 12A due to the effect of stiffness or curl of the sheet P, the behavior of the sheet P between the inlet roller pair 11 and the pressing roller 14 is as shown in FIG. Alternatively, as shown in FIG. 13A, the sheet P may be in a curved state. Then, due to the difference in the behavior of the sheet P, when the sheet P is stopped after X1 [ms] or X2 [mm] after the entrance sensor 21 detects the leading edge of the sheet, FIG. As shown in FIG. 13B, the stop position of the sheet P varies.

  In addition, it is impossible to strictly manage the diameters of the inlet roller pair 11 and the pressing roller 14, and a mechanical dimensional error always occurs. For this reason, there is an error from the ideal diameter of the inlet roller pair 11 and the pressing roller 14, so that the conveyance amount of the sheet P in one rotation of the roller is larger or shorter than ideal. The longer the distance that the sheet P is conveyed by the inlet roller pair 11 and the pressing roller 14, the more the error occurs in the conveyance amount of the sheet P, and as a result, the amount of protrusion of the sheet P increases. The folding position of the sheet P changes due to an error. This is the same even if there is a sheet detection sensor between the inlet roller pair 11 and the pressing roller 14 in the through conveyance path W1.

  Therefore, in this configuration example, as shown in FIG. 1, the sheet detection sensor 22 provided on the downstream side in the sheet conveyance direction of the pressing roller 14 in the through conveyance path W1 detects the sheet leading edge of the sheet P, and the detection timing thereof. Is used as a trigger to stop the seat. Thereby, the variation in the behavior of the sheet P between the inlet roller pair 11 and the pressing roller 14 can be eliminated, and the stop position accuracy of the sheet P can be improved.

  That is, after the sheet P is sandwiched between the pressing roller 14 and the first forward / reverse roller 13, the sheet leading edge is detected by the sheet detection sensor 22, and the distance from the detected position to the stop of the sheet P is designated. ing. For this reason, even if the behavior of the sheet P between the inlet roller pair 11 and the pressing roller 14 varies as shown in FIG. 12A and FIG. The behavior of the sheet P with the roller 14 does not affect the stop position of the sheet leading end.

  Further, the detection position of the sheet front end by the sheet detection sensor 22 is a position close to the target sheet front end stop position. As a result, the influence of the behavior of the sheet P after the detection of the sheet front end by the sheet detection sensor 22 until the sheet P is stopped is detected by the sheet detection sensor provided on the upstream side of the inlet roller pair 11 in the sheet conveyance direction. It can be made smaller than the case where it detects. Therefore, the variation in the sheet front end stop position due to the behavior of the sheet P from the detection timing of the sheet front end by the sheet detection sensor 22 to the stop of the sheet P is suppressed, and the variation in the protrusion amount can be suppressed. Therefore, since the variation in the protrusion amount is suppressed, the accuracy of the folding position of the sheet P in the sheet conveying direction can be improved.

[Configuration example 2]
FIG. 14 is a schematic diagram illustrating a main part of the folding processing device 1 according to Configuration Example 2.
In the folding processing device 1 of this configuration example, as shown in FIG. 14, a sensor moving device 90 that moves the sheet detection sensor 22 along the sheet conveyance direction in the through conveyance path W1 is provided. The sensor moving device 90 includes a holding belt 91, a driving roller 92, a driven roller 93, a timing belt 94, and a driving motor 90m. The holding belt 91 is rotatably stretched by a driving roller 92 and a driven roller 93, and holds the sheet detection sensor 22 on the outer peripheral surface. Then, by transmitting the rotational driving force from the driving motor 90m to the driving roller 92 via the timing belt 94, the driving roller 92 rotates and the holding belt 91 also rotates accordingly. As the holding belt 91 rotates in this manner, the sheet detection sensor 22 can be moved along the sheet conveyance direction in the through conveyance path W1.

  The direction of movement of the sheet detection sensor 22 is switched between forward rotation and reverse rotation of the drive motor 90m, whereby the rotation direction of the drive roller 92 is switched between the clockwise direction in the figure and the counterclockwise direction in the figure. Along with this, the rotation direction of the timing belt 94 can be changed by turning it clockwise in the figure and counterclockwise in the figure.

  In the present configuration example, the sheet detection sensor 22 is moved along the sheet conveyance direction in the through conveyance path W1 by the sensor moving device 90 according to the set value of the sheet size and the folding position of the sheet P. Then, the sheet detection sensor 22 is positioned at a position where the sheet leading edge can be detected immediately before the sheet leading edge stop position.

  As a result, even when an ideal error occurs in the diameters of the inlet roller pair 11 and the pressing roller 14, the influence of the conveyance amount of the sheet P due to the error can be suppressed to a minimum. The stop position accuracy can be improved.

  Here, the position of the sheet detection sensor 22 in the through conveyance path W1 needs to be a position away from the sheet leading edge stop position by a distance more than a distance necessary for through-up of the pressing roller 14 to the upstream side in the sheet conveyance direction. . The values are the through-up time t [s] of the first forward / reverse rotation motor 13m that rotates the pressing roller 14 via the first forward / reverse rotation roller 13, and the sheet conveyance speed V [mm / s] of the pressing roller 14. Then, it becomes V × t [mm] or more. Therefore, the position of the sheet detection sensor 22 in the through conveyance path W1 needs to be set to V × t [mm] or more and upstream of the sheet front end stop position with respect to the sheet conveyance direction. Further, if there is an adjustment value obtained experimentally, it is necessary to take that into consideration.

  For simplicity, when the adjustment value is not considered, the position of the sheet detection sensor 22 in the through conveyance path W1 may be determined as follows. For example, the through-up time of the first forward / reverse rotation motor 13m that rotates the pressing roller 14 via the first forward / reverse rotation roller 13 is 20 [ms], and the conveyance speed of the pressing roller 14 is 500 [mm / s]. . In this case, the sheet P is conveyed by 10 [mm] after the stop signal is sent to the first forward / reverse rotation motor 13m until the first forward / reverse rotation motor 13m actually stops. Therefore, it is only necessary to move the sheet detection sensor 22 to a position upstream of the sheet leading end stop position by 10 [mm] upstream in the sheet conveyance direction.

[Configuration example 3]
FIG. 15 is a schematic diagram illustrating a main part of the folding processing device 1 according to the configuration example 3. As illustrated in FIG.
In the folding processing apparatus 1 of this configuration example, as shown in FIG. 15, four sheet detection sensors 22, 23, 24, and 25 are sequentially arranged along the sheet conveyance direction in the through conveyance path W <b> 1. Thereby, the sheet detection sensor used for the sheet leading edge detection is selectively changed according to the folding length and the sheet size.

  In the folding processing device 1 of this configuration example, the sheet detection sensor cannot be moved to a free position by the sensor moving device 90 unlike the folding processing device 1 of the configuration example 2. On the other hand, since the sensor moving device 90 is not provided, there are advantages in terms of cost and simplification of the layout.

What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.
(Aspect A)
A first sheet conveying means such as an inlet roller pair 11 that holds a part of the sheet such as the sheet P and applies a conveying force to the sheet, and is disposed downstream of the first sheet conveying means in the sheet conveying direction. A second sheet conveying means such as a first forward / reverse rotation roller 13 and a pressing roller 14 that holds a part and applies a conveying force to the sheet, and a part of the sheet are held by the first sheet conveying means, and the second The sheet is conveyed by sandwiching a folded portion formed in the sheet portion between the first sheet conveying means and the second sheet conveying means by applying a conveying force to the sheet that is returned to the upstream side in the sheet conveying direction by the sheet conveying means. In a sheet folding apparatus such as a folding processing apparatus 1 including a first forward / reverse rotation roller 13 and a folding part forming means such as a first folding roller 12 for forming a folding part in A sheet leading edge detecting means such as a sheet detecting sensor 22 for detecting the leading edge of the sheet is provided downstream of the sheet conveying means in the sheet conveying direction or substantially at the same position, and based on the detection timing of the sheet leading edge detecting means The sheet is conveyed so that the leading edge of the sheet protrudes from the second sheet conveying unit immediately before applying the conveying force for returning to the sheet. According to this, as described in the above embodiment, it is possible to suppress variation in the formation position of the folded portion of the sheet in the sheet conveying direction.
(Aspect B)
In (Aspect A), the position of the sheet leading edge detection means in the sheet conveyance direction is changed according to the sheet size. According to this, as described in the above embodiment, it is possible to minimize the influence of the conveyance amount due to an error from the ideal roller diameter, and it is possible to improve the sheet stop position accuracy.
(Aspect C)
In (Aspect A), the position of the sheet leading edge detection means in the sheet conveyance direction is changed according to the set value of the sheet folding position. According to this, as described in the above embodiment, it is possible to minimize the influence of the conveyance amount due to an error from the ideal roller diameter, and it is possible to improve the sheet stop position accuracy.
(Aspect D)
In (Aspect A), the sheet conveyance amount from when the sheet leading edge detection unit detects the sheet leading edge until the sheet stops is adjusted according to the sheet information. According to this, as described in the above embodiment, the protruding amount of the sheet can be set appropriately.

(Aspect E)
In (Aspect D), the sheet information is at least one of a sheet thickness and a sheet type. According to this, as described in the above embodiment, it is possible to appropriately set the sheet protrusion amount suitable for the sheet thickness and the sheet type.
(Aspect F)
An image forming apparatus including an image forming unit such as an image forming unit 110 that forms an image on a sheet and a sheet folding unit that is provided in the apparatus body and performs a folding process on the sheet. The sheet folding apparatus according to (Aspect A), (Aspect B), (Aspect C), (Aspect D) or (Aspect E) was used. According to this, as described in the above embodiment, it is possible to reduce the variation in the folding position of the sheet on which the image is formed.
(Aspect G)
An image forming system comprising: an image forming apparatus that forms an image on a sheet; and a sheet folding apparatus that is provided separately from the image forming apparatus and performs a folding process on a sheet on which an image is formed by the image forming apparatus. As the sheet folding apparatus, the sheet folding apparatus of (Aspect A), (Aspect B), (Aspect C), (Aspect D) or (Aspect E) was used. According to this, as described in the above embodiment, it is possible to reduce the variation in the folding position of the sheet on which the image is formed.

DESCRIPTION OF SYMBOLS 1 Folding processing apparatus 2 Image forming apparatus 3 Sheet post-processing apparatus 4 Charging apparatus 5 Developing apparatus 6 Cleaning apparatus 7 Photosensitive drum 8 Lubricant coating apparatus 9 Primary transfer roller 10 Intermediate transfer belt 11 Inlet roller pair 11a Press roller 11b Drive roller 11m Inlet motor 11s Pressure spring 12 First folding roller 12s Pressure spring 13 First forward / reverse roller 13m First forward / reverse motor 14 Pressing roller 14s Pressure spring 15 Second folding roller 15s Pressure spring 16 Second forward / reverse roller Pair 16a Press roller 16b Drive roller 16m Second forward / reverse motor 16s Pressure spring 17 Belt cleaning device 18 Optical writing device 19 Image forming device 20 Photosensitive drum 21 Entrance sensor 22 Sheet detection sensor 23 Sheet detection sensor 24 C Detection sensor 25 Sheet detection sensor 26 Sheet detection sensor 30 Document table 32 Contact glass 33 First traveling body 34 Second traveling body 35 Imaging lens 36 Reading sensor 40 Cleaning unit 42 Feed roller 43 Paper bank 44 Feed cassette 45 Separating roller 46 Feeding path 47 Conveying roller 48 Feeding path 49 Registration roller 50 Feeding roller 51 Manual feed tray 52 Separating roller 53 Feeding path 55 Switching claw 56 Discharge roller 60 Tandem image forming unit 61 Exposure device 62 Secondary transfer roller 63 Secondary Transfer belt stretching roller 64 Secondary transfer belt 65 Fixing device 66 Fixing belt 67 Pressure roller 68 Sheet reversing device 69 Secondary transfer device 70 Developing device 71 First support roller 72 Second support roller 73 Third support roller 74 Primary transfer roller DESCRIPTION OF SYMBOLS 0 Charging device 90 Sensor moving device 90m Drive motor 91 Holding belt 92 Drive roller 93 Driven roller 94 Timing belt 100 Printer unit 101 Image forming apparatus main body 110 Image forming unit 111 Image forming station 112 Intermediate transfer belt 114 Support roller 115 Secondary transfer roller 116 toner container 120 feeding unit 121 feeding tray 122 pickup roller 123 feeding conveyance roller 130 feeding conveyance path 140 secondary transfer unit 150 fixing device 150a fixing roller 150b pressure roller 160 discharge conveyance path 161 branch claw 162 branch conveyance Roller 170 Double-sided conveyance path 200 Feed unit 300 Scanner unit 302 Entrance sensor 303 Entrance roller pair 304 Branch claw 305 Discharge roller pair 310 Binding tool 340 Transport path 341 Branch path 400 Document transport 500 image reader 501 contact glass

JP 2007-277006 A

Claims (13)

A first conveyance roller pair for nipping and conveying the sheet;
A second conveying roller pair disposed downstream of the first conveying roller pair in the sheet conveying direction, and sandwiching the sheet and conveying the sheet;
The sheet folding device and a fold roller pair folding the sheet by sandwiching the sheet between the previous SL first conveying roller pair and the second pair of conveying rollers,
Sheet detecting means for detecting a sheet on the downstream side in the sheet conveying direction of the second conveying roller pair ;
A third conveying roller pair for conveying a sheet folded by the folding roller pair on the downstream side in the sheet conveying direction of the pair of folding rollers;
Second sheet detecting means for detecting a sheet on the downstream side in the sheet conveying direction of the third conveying roller pair;
One roller of the second conveying roller pair is capable of rotating in the forward and reverse directions and doubles as one of the folding roller pair,
Said one roller is rotated forward one of the rollers the conveys the sheet to the sheet conveying direction downstream side, Shi feed transportable first place quantitatively the sheet conveyance direction downstream side of the sheet detecting means said seat After that, the one roller is reversely rotated to return the sheet to the upstream side in the sheet conveying direction, and a folding portion formed on the sheet is sent to the pair of folding rollers ,
After the folded portion of the sheet has passed through the nip of the third conveying roller pair, the sheet is conveyed by a second predetermined amount downstream in the sheet conveying direction from the second sheet detecting means, and the sheet conveyance is stopped. A sheet folding apparatus.   In the sheet folding apparatus according to claim 1,
  The rotation of the third conveying roller pair is started in the sheet returning direction, and the reverse rotation of the one of the folding roller pairs is started, whereby the one roller and the third conveying roller pair are A sheet folding apparatus characterized by forming a bend in a sheet portion therebetween.   In the sheet folding apparatus according to claim 1 or 2,
  A second folding roller pair that folds the sheet folded by the folding roller pair on the downstream side in the sheet conveying direction of the folding roller pair;
  The sheet folding apparatus according to claim 1, wherein the one roller of the second conveying roller pair also serves as one of the second folding roller pair.   A first conveyance roller pair for nipping and conveying the sheet;
  A second conveying roller pair disposed downstream of the first conveying roller pair in the sheet conveying direction, and sandwiching the sheet and conveying the sheet;
  In a sheet folding apparatus comprising a pair of folding rollers for folding the sheet by sandwiching the sheet between the first conveying roller pair and the second conveying roller pair,
  Sheet detecting means for detecting a sheet on the downstream side in the sheet conveying direction of the second conveying roller pair;
  A second folding roller pair for folding a sheet folded by the folding roller pair on the downstream side in the sheet conveying direction of the folding roller pair;
  One roller of the second conveying roller pair is capable of rotating in the forward and reverse directions and doubles as one of the folding roller pair,
  The one roller rotates the one roller forward to convey the sheet downstream in the sheet conveying direction, conveys a predetermined amount of the sheet to the downstream side in the sheet conveying direction from the sheet detecting means, The roller is reversed to return the sheet to the upstream side in the sheet conveying direction, and the folding portion formed on the sheet is sent to the pair of folding rollers,
  The sheet folding apparatus according to claim 1, wherein the one roller of the second conveying roller pair also serves as one of the second folding roller pair. In the sheet folding apparatus according to any one of claims 1 to 4 ,
The sheet is sandwiched between the first conveying roller pair and the second conveying roller pair, and the one roller is reversed so that the sheet is transferred between the first conveying roller pair and the second conveying roller pair. A sheet folding apparatus that forms a bend. In the sheet folding apparatus according to any one of claims 1 to 5 ,
A sheet folding apparatus, wherein the position of the sheet detecting means in the sheet conveying direction is changed according to a sheet size. The sheet folding device according to any one of claims 1乃Itaru 6,
A sheet folding apparatus, wherein the position of the sheet detecting means in the sheet conveying direction is changed according to a set value of a sheet folding position. The sheet folding device according to any one of claims 1乃Itaru 7,
A sheet folding apparatus, wherein a sheet conveyance amount from when a sheet is detected by the sheet detection unit to when the sheet stops is adjusted according to sheet information. The sheet folding apparatus according to claim 8 .
The sheet folding apparatus, wherein the sheet information is at least one of a sheet thickness and a sheet type. The sheet folding apparatus according to any one of claims 1 to 9,
The sheet folding apparatus according to claim 1, wherein the one of the second conveying roller pairs is a driving roller. In the sheet folding apparatus according to claim 10,
2. The sheet folding apparatus according to claim 1, wherein the other roller that forms a pair with the one of the second conveying roller pairs is a driven roller. Image forming means for forming an image on a sheet;
In an image forming apparatus provided with a sheet folding unit that is provided in the apparatus main body and performs a folding process on a sheet,
An image forming apparatus using the sheet folding apparatus according to claim 1 as the sheet folding means. An image forming apparatus for forming an image on a sheet;
In an image forming system provided with a sheet folding device that is provided separately from the image forming device and performs a folding process on a sheet on which an image is formed by the image forming device,
An image forming system using the sheet folding device according to claim 1 as the sheet folding device.

Images