JP5657344B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that sequentially forms images on both front and back sides of a sheet, and relates to an improvement in a sheet circulation mechanism that reverses a front side and a back side of an image formed on one side and forms an image on the back side.

  Conventionally, this type of image forming apparatus is widely known as a printer, a copier, a facsimile machine, and the like. The image forming apparatus includes a sheet feeding unit, an image forming unit, and a post-processing unit. And a bookbinding process such as bookbinding finishing is performed in the post-processing section.

  For example, in Patent Document 1, an image forming unit is arranged above a paper feed cassette, an image forming unit that carries out an image-formed sheet from a paper discharge port, and a post-processing unit is arranged in the paper discharge port. An apparatus for binding and stacking the formed sheets and binding them together is disclosed.

  In this document, a post-processing device is connected to the image forming apparatus, the sheets on which the image is formed are aligned and collected by the post-processing device, and the center of the sheet is bound and folded. The image forming unit is provided with a sheet feeding path for feeding a sheet from the sheet feeding unit and a reversing path for reversing the sheet with an image formed on one side thereof and retransmitting the sheet to the image forming unit. This inversion path is a path configuration in which the sheet sent from the image forming unit (printing drum) is switched back to reverse the front and back, and this document discloses a mechanism for disposing the switchback path inside the image forming apparatus. .

  Japanese Patent Application Laid-Open No. 2004-228561 has an apparatus configuration in which a switchback path is provided to reverse the sheet discharged from the image forming unit for double-sided printing, the sheet conveyance direction is reversed, and the sheet is circulated again to the image forming unit. It is disclosed.

JP 2008-184325 A JP 2003-002503 A

  As described above, when an image is formed on one side by the image forming unit and the sheet is reversed to form an image on the back side, a reversing path is conventionally arranged inside the housing of the image forming apparatus (unit) as in Patent Document 1. doing. For this reason, there is a problem that the apparatus becomes large in the space occupied by the inversion path.

  Therefore, it is also known that a reversing path for reversing the front and back of the sheet is transferred back to the apparatus after the front end of the sheet is carried out to a paper discharge stacker and then switched back. However, carrying out the leading edge of the sheet to the paper discharge stacker sometimes pulls out the sheet when the user takes out the already stacked sheet. In this case, sheet jam occurs. At the same time, when the leading edge of the sheet is temporarily carried out onto the sheet discharge tray, the stacking posture is disturbed by shifting the sheet (the uppermost sheet) on which the sheet is already stacked, and in some cases, the uppermost sheet is placed outside the tray. There is a problem of extrusion.

  In view of this, the present inventor, in an apparatus configuration in which a sheet storage discharge tray and a post-processing processing tray are arranged downstream of the image forming unit, the path for guiding the sheet to the discharge tray is a curved path. The idea is that the path for guiding the tray is constituted by a substantially straight path, and the switchback path of the reversing path for reversing the sheet is guided to the processing tray side. As a result, it has been found that the above-mentioned problems can be solved.

  The present invention can reduce the size of an apparatus in an apparatus configuration in which a sheet image-formed on one side is turned upside down to form an image on the back side, and at the same time, an image forming apparatus that does not cause sheet jam in a path for turning the sheet upside down. Is the issue.

  In order to achieve the above object, the present invention arranges a processing tray that folds a sheet on the downstream side of the image forming unit, and a single sheet stack tray that stores a sheet sent from the image forming unit without folding processing, An image forming unit is provided with a substantially straight path for transferring the sheet sent from the image forming unit in the same direction and guiding it to the processing tray, and a curved path for making a U-turn and transferring it in the opposite direction and guiding it to the single sheet stack tray. After the sheet sent from the sheet is carried into the processing tray by the substantially straight path, the conveyance direction is reversed and the sheet is returned again to the image forming unit.

  Further, the configuration will be described. An image forming unit that forms an image on a sheet, a processing tray that folds the sheet sent from the image forming unit, and a single storage unit that stores the sheet sent from the image forming unit without folding processing. A sheet stack tray, a folded sheet stack tray for storing sheets sent from the processing tray, a paper discharge path for selectively guiding the sheets sent from the image forming unit to the processing tray and the single sheet stack tray, and this discharge A path switching unit disposed in the paper path; and a reversing path for reversing the sheet sent from the image forming unit and sending the sheet to the image forming unit again.

  The paper discharge path includes a substantially linear path for transferring the sheet sent from the image forming unit in the same direction and guiding it to the processing tray, and a U-turn for transferring the sheet sent from the image forming unit in the opposite direction. Branched into a curved path guided to a single sheet stack tray, and the paper discharge path is composed of a substantially straight path and a curved path branched in two directions. This substantially straight path is a sheet sent from the image forming unit. Are transferred in the same direction and guided to the processing tray, and this curved path causes the sheet sent from the image forming unit to be U-turned and guided to the single sheet stack tray, and the reverse path is sent from the image forming unit. After the front end of the sheet is carried out to the processing tray, the conveyance direction is reversed and the sheet is returned to the image forming unit again.

  The present invention guides the sheet sent from the image forming unit to a substantially straight path in the same direction as the carry-out direction and guides the leading end of the sheet to the processing tray, and then returns the sheet to the image forming unit by reversing the conveying direction. The following effects can be obtained because of this.

  Since the front end of the sheet on which the image is formed on one side is transported to the processing tray by a substantially linear path, the transport direction is reversed and returned to the image forming unit, so that the user does not pull out the front end of the sheet transported to the processing tray.

  At the same time, a stack tray for storing sheets on the downstream side of the image forming unit and a processing tray for folding the sheets are arranged in a substantially straight path in the same direction as the sheet sent from the image forming unit. Therefore, a stress such as a curved path does not act on the sheet that is reversed upside down and retransmitted to the image forming unit, and there is little possibility of causing a sheet jam.

  Further, by arranging alignment means (regulating member described later) for positioning the sheet on the processing tray, even if a positional deviation occurs in the sheet already stored in the sheet temporarily loaded into the processing tray, this alignment means The position can be corrected.

1 is an explanatory diagram of an overall configuration of an image forming apparatus according to the present invention. FIG. 2 is an explanatory diagram illustrating a configuration of an image forming unit in the apparatus of FIG. 1. Explanatory drawing which shows the structure of the post-processing part in the apparatus of FIG. (A) shows the structure of a side alignment board, (b) is a structure explanatory drawing of a binding process means. FIG. 3 is a configuration explanatory diagram of a folding processing unit. FIG. The open view of a post-processing unit. The path | route opening of a post-processing unit is shown, (a) is an open state figure of a folded sheet carrying-out path | route, (b) is the open state figure of a single sheet carrying-out path | route. Explanatory drawing of the control structure concerning this invention.

  An image forming apparatus C according to the present invention includes an image forming unit A that forms an image on a sheet, and a post-processing unit B that collects and stacks sheets formed with the unit and performs bookbinding. The image forming unit A shown in FIG. 1 includes a sheet feeding unit A1 that supplies a sheet, an image forming unit A2 that forms an image on a sheet fed from the sheet feeding unit, and a post-processing unit B that follows the sheet on which the image has been formed. The paper discharge unit A3 is carried out.

  The sheet feeding unit A1 supplies the sheet to the image forming unit A2, and the image forming unit A2 forms an image on the sheet and carries it out from the sheet discharging unit A3 to the downstream post-processing unit B. The post-processing unit B includes a post-processing unit B1 that stacks and stacks sheets sent from the paper discharge unit A3 and performs bookbinding processing, and a stack unit B2. The image forming unit A and the post-processing unit B shown in FIG. 1 are configured as separate units and are integrally stored in an apparatus frame 60 described later. The configuration of each unit will be described.

[Image forming unit]
The configuration of the image forming unit A will be described with reference to FIG. In the image forming unit A, a paper feeding unit A1, an image forming unit A2, a paper discharge unit A3, and a front / back reversing unit A4 are incorporated in an outer casing 10.

  The sheet feeding unit A1 includes a single or a plurality of sheet feeding cassettes 11 (11a, 11b) and a sheet feeding roller 12 that feeds out sheets from each cassette. The sheet feeding cassette 11 is detachably attached to the outer casing 10. ing. Although not shown, each sheet cassette 11 is provided with a separation unit that separates the sheet fed by the sheet feed roller 12 into one sheet. This separation means is composed of a separation claw, a separation pad, a separation roller, etc. for preventing the double feeding of sheets.

  The image forming unit A2 is disposed on the downstream side (upper side in FIG. 1) of the sheet feeding unit A1 via the sheet feeding path 13. The sheet feeding path 13 is provided with a registration roller 14 that corrects the skew of the sheet leading edge, and aligns the leading edge of the sheet sent from the sheet feeding unit A1.

  The image forming unit A2 has a detailed structure shown in FIG. 2, but forms an image on the sheet sent from the registration roller 14. The illustrated apparatus shows a case where the image forming unit is constituted by an electrostatic transfer image forming mechanism. In addition, an image forming mechanism such as an ink jet type, an offset type, or a thermal transfer type can be adopted as the image forming unit A2.

  A transfer unit 15 is disposed on the downstream side of the registration roller 14, and a transfer roll (charger roll) 18 and an intermediate transfer belt 21 are opposed to the transfer unit 15 via a sheet conveyance path. The toner image formed on the intermediate transfer belt 21 is transferred onto the sheet by the transfer roll 18. Therefore, the surface of the transfer roll 18 is charged (charged).

  The intermediate transfer belt 21 rotates in the direction of the arrow in FIG. 2 (clockwise), and the Y, M, C, and K electrostatic drum 16 (16a, 16b, 16c, 16d) and the transfer roll 17 (17a, 17b, 17c, 17d) are arranged opposite to each other.

  Each electrostatic drum 16 is provided with a laser head 19 (19a, 19b, 19c, 19d) and a developing device 20 (20a, 20b, 20c, 20d). 22 (22 a, 22 b, 22 c, 22 d) shown in the figure is a cleaner arranged on each electrostatic drum 16, and 23 shown in the figure is a belt cleaner arranged on the intermediate transfer belt 21.

  With such a configuration, the laser head 19 is controlled based on data transferred to an image control unit (not shown), and an electrostatic latent image is formed on the electrostatic drum 16 for each color component of YMCK. Then, a toner ink is attached to the electrostatic latent image by the developing device 20 and electrostatically adsorbed to the intermediate transfer belt 21 by a transfer roll (charger) 17.

  As a result, the YMCK color component images are combined on the intermediate transfer belt 21 and transferred to the transfer unit 15 by the rotation of the belt. The image formed on the intermediate transfer belt 21 and the sheet whose timing is adjusted by the registration roller 14 are fed to the transfer unit 15, and the image on the intermediate transfer belt 21 is transferred to the sheet surface by the transfer roll 18. A fixing device 24 is provided on the downstream side of the transfer unit 15 to heat and fix the image transferred on the sheet.

  In particular, in the apparatus shown in FIG. 1, the sheet feeding direction Sk for feeding out the sheet from the sheet feeding cassette 11 of the sheet feeding unit A1 is arranged in a substantially horizontal direction, and the sheet is fed to the transfer unit 15 from now on. The sheet feeding direction Sy of the paper path 13 is arranged in a substantially vertical direction, and the running direction Vk of the intermediate transfer belt 21 is arranged in a horizontal direction with respect to the sheet feeding direction Sk. As a result, as shown in FIG. 1, the paper feed cassette 11 and the intermediate transfer belt 21 are arranged substantially in parallel, and the image forming unit A is made compact.

  A paper discharge unit A3 is disposed as a paper discharge path 25 on the downstream side of the fixing device 24. The paper discharge path 25 is connected to the fixing device 24, and the heated and fixed sheet is carried out to a storage stacker 32 (33) of the post-processing unit B described later. The sheet discharge direction Sz of the sheet discharge path 25 is set in a direction substantially opposite to the sheet feeding direction Sk for feeding out the sheet from the sheet feeding cassette 11. With such a layout configuration, the intermediate transfer belt 21 and the image forming mechanism (such as the electrostatic drum 16 and the developing device 20) are disposed above the sheet feeding cassette 11, and a processing tray 34 for post-processing the sheet is disposed above the intermediate transfer belt 21. Therefore, the apparatus is made compact.

[Front-side reverse part]
The structure of the front / back reversing part A4 for reversing the front side of the sheet imaged on one side by the transfer unit 15 and forming the image on the back side will be described with reference to FIGS. In the paper discharge unit A3, a circulation path 27 that reverses the front and back of the sheet sent from the paper discharge path 25 and guides it to the transfer unit 15 again is disposed. The circulation path 27 is branched and connected from the paper discharge path 25 as shown in a part of FIG. 3, and the sheet carried out along the paper discharge path 25 is switched back (reversing the conveying direction). Carry in again. For this reason, a guide flapper 25f is provided between the paper discharge path 25 and the circulation path 27, and guides the trailing edge of the sheet carried out of the paper discharge path 25 to the circulation path 27 by a driving means (such as an electromagnetic solenoid) (not shown). .

  As shown in FIG. 2, the circulation path 27 is configured to have a path shape in which the switch-backed sheet is turned upside down and guided to the registration roller 14, and an image is formed on the back side by the transfer unit 15. Then, the sheet on which the image is formed on the back surface by the transfer unit 15 is carried out from the paper discharge path 25 to the downstream side.

  As described above, the post-processing unit B, which will be described later, is arranged in the paper discharge path 25 of the image forming unit A, and the processing tray 34 of the post-processing unit B is arranged so as to be connected to the paper discharge path 25 ( (See FIG. 1). Then, the leading edge of the sheet unloaded from the sheet discharge path 25 of the image forming unit A is loaded onto the processing tray 34 and returned to the circulation path 27 from the trailing edge of the sheet.

[Post-processing unit]
The configuration of the post-processing unit B will be described with reference to FIGS. The post-processing unit B is disposed above the image forming unit A, and includes a post-processing unit B1 and a stack unit B2. The post-processing unit B1 arranges and stacks the sheets sent from the image forming unit A, “binding function” for binding the aligned sheet bundle, and “folding processing function” for folding the sheet bundle Is provided.

  The copy alignment function accumulates the sheets sent from the image forming unit A in the order of pages on the processing tray. In addition, the binding function performs saddle stitching at the center of the bundle of sheets that are collected and aligned, and the folding processing function folds the bundle at the center binding position. As a result, the sheets on which images are formed on one side or both sides are aligned in the order of pages, and the center portion of the sheets is bound and folded to be magazine finished. The stack B2 includes a single sheet stacker 32 that stores sheets sent from the image forming unit A without magazine finishing and a folded sheet stacker 33 that stores magazine-finished sheet bundles.

  As shown in FIG. 3, the post-processing unit B1 and the stacking unit B2 are disposed in the outer casing 30, the post-processing unit B1 is disposed below, the stacking unit B2 is disposed above, and the stacking unit B2 is disposed above the single sheet stacker 32. A folded sheet stacker 33 is arranged. Hereinafter, the post-processing unit B1 and the stack unit B2 will be described in this order.

[Post-processing section]
The configuration of the post-processing unit B1 will be described with reference to FIG. The post-processing unit B1 includes a processing tray 34, and a “binding processing unit 50”, a “folding processing unit 55”, and a “sheet bundle transporting unit 46” arranged on the tray.

"Processing tray"
As shown in FIG. 3, the processing tray 34 is disposed on the downstream side of the paper discharge path 25 of the image forming unit A, and the sheets conveyed from the paper discharge path 25 are aligned and collected. Therefore, a paper discharge path 25x is connected to the path exit 25a of the paper discharge path 25, and the processing tray 34 is arranged so as to be connected to the paper discharge path 25x.

  As shown in FIG. 3, the paper discharge path 25x is arranged in the same direction as the sheet paper discharge direction Sz of the paper discharge path 25 and has a substantially linear shape (hereinafter, this paper discharge path is referred to as a “straight path”). Called). The processing tray 34 is formed in a tray shape having a paper loading surface 34a, and stacks and stores sheets sent from the path exit of the linear path 25x.

  The processing tray 34 is provided with an elevating roller 36. The elevating roller 36 is not shown so as to move up and down between an operating position that engages with the uppermost sheet on the paper loading surface 34a and a retracted position that is retracted. Elevating mechanism is provided. When the sheet enters the processing tray 34, the elevating roller 36 stands by at the standby position and descends to the operating position (position in contact with the sheet) after the end of the sheet enters, and at the same time, counterclockwise in FIG. ).

  The processing tray 34 is provided with a regulating member 37 that regulates the position of the trailing edge (or the leading edge) of the sheet, and aligns the sheet sent from the linear path 25x with a preset reference position. In the apparatus shown in FIG. 3, a regulating member 37 that regulates the trailing edge of the sheet in the sheet discharge direction is configured as a butting member that protrudes upward in the stacking direction from the paper loading surface 34a. The regulating member 37 may be constituted by a protruding piece fixed to the paper mounting surface 34a. The illustrated one is constituted by the same unit as a sheet bundle transfer means 46 described later.

"Side alignment plate"
The processing tray 34 is provided with side alignment plates 38L and 38R for regulating the position of the sheet side edge. Although the structure is shown in FIG. 4A, the side alignment plates 38L and 38R are aligned with reference to the center of the sheet carried into the processing tray 34 and the left and right side edges of the sheet as a reference. Adopt either side reference structure.

  FIG. 4A shows a center reference alignment mechanism, in which a left alignment plate 38L that engages with the left edge of the sheet on the processing tray 34 and a right alignment plate 38R that engages with the right edge of the sheet are processed. It is fitted and supported in a guide groove (not shown) of the tray 34 so as to be movable in the sheet width direction. As shown in FIG. 4A, a pair of pulleys 39a and 39b are disposed along the guide groove on the bottom of the processing tray 34, and a belt 40 is stretched over the pulleys 39a and 39b. The left and right alignment plates 38L and 38R are fixed to the belt 40. One of the pulleys 39b is connected to an alignment motor MZ1, and the other is connected to an alignment motor MZ2.

  The left alignment plate 38L and the right alignment plate 38R, which are formed as a pair on the left and right sides in such a configuration, are moved to the left and right in the sheet width direction by driving the alignment motors MZ1 and MZ2. Therefore, the left and right alignment motors MZ1 and MZ2 are synchronously driven to rotate in the opposite direction by the same amount, so that the sheets carried on the processing tray can be aligned on the center basis.

"Sheet bundle transfer means"
The configuration of the sheet bundle transfer means 46 will be described with reference to FIG. In the above-described processing tray 34, an accumulation reference position Px, a binding position Py, and a folding processing position Pz are set. As shown in FIG. 3, each of these positions has an accumulation reference position Px and then a folding processing position Pz arranged upstream along the sheet carry-in direction Sq, and a binding position Py is set downstream of the folding processing position Pz. Yes.

  The stacking reference position Px is set as a reference for stacking sheets on the paper loading surface 34a of the processing tray 34, and the above-described regulating member 37 is disposed at this position. The folding processing position Py is arranged at a position for folding the sheet, and a folding processing means 55 described later is arranged at this position. Further, the binding position Py is set to a position where the sheet bundle is bound, and a binding processing means (staple means) 50 described later is disposed at this position.

  Therefore, the processing tray 34 is provided with a sheet bundle transfer means 46 for moving the stacked sheet bundle in the order of the binding position Py and the folding processing position Pz. The sheet bundle transfer means 46 will be described with reference to FIG. The sheet bundle transfer means 46 shown in the figure is composed of a rear end transfer means 46A for moving the position of the sheet rear end and a front end transfer means 46B for aligning the front ends of the sheets.

  The trailing edge transfer means 46A moves the regulating member 37, which engages with the trailing edge of the sheet stored in the paper loading surface 34a, along the sheet carry-in direction Sq. Therefore, the restricting member 37 is fixed to the moving frame 41, and the moving frame 41 is attached to an apparatus frame (not shown) so as to be movable along the paper mounting surface 34a. The moving frame 41 is provided with a rack 42r, and a first shift motor Ms1 is connected to a pinion 42p meshing with the rack.

  On the other hand, as shown in FIG. 3, the leading edge transfer means 46 </ b> B has an engagement piece 43 that engages with the leading edge of the sheet stored on the paper loading surface 34 a attached to the belt 44, and a pulley 45 that supports the belt 44. The second shift motor Ms2 is connected. Further, a support shaft 43x is provided at one end of the engagement piece 43. When a jam occurs in the apparatus, the engagement piece 43 can be opened and closed at the position of the broken line in the figure with the support shaft 43x as the center.

  Accordingly, by synchronizing the first and second shift motors Ms1 and Ms2 and rotating forward and backward by the same amount, the sheet bundle on the paper placement surface is moved along the paper placement surface 34a with the rear end held by the regulating member 37. It moves between the accumulation reference position Px, the binding position Py, and the folding processing position Pz.

  Note that the sheet bundle transfer means 46 is not limited to a mechanism constituted by the trailing edge transfer means 46A and the leading edge transfer means 46B as shown in the figure, and for example, a grip for gripping the sheet bundle on one of the rear end portion and the leading end portion of the sheet bundle. A clip conveying mechanism that provides a mechanism and moves the position of the grip mechanism along the paper mounting surface 34a may be employed. In addition, a mechanism that tilts the paper mounting surface 34a by a predetermined angle and holds the sheet in a posture of dropping by its own weight, and moves the position of the regulating member 37 that abuts and regulates the lower edge of the sheet along the paper mounting surface 34a may be adopted. Is possible.

[Binding processing means]
In the processing tray 34, a binding processing unit (stapling unit) 50 is disposed at the binding position Py. In the illustrated apparatus, the staple means 50 (50A, 50B) is disposed at two positions apart from each other as shown in FIG. 4A in order to staple two positions at the center of the sheet bundle. The configuration of the stapling means 50 will be described with reference to FIG. The stapling means (binding processing means) 50 includes a driver mechanism unit 50a and a clincher mechanism unit 50b. The driver mechanism unit 50a includes a driver member 52 that inserts staples into a sheet bundle and a cartridge 51 that stores the staples. Although not shown, the cartridge 51 has a built-in sheet-shaped or roll-shaped blank needle in which straight needles are connected in a band shape, and is configured to sequentially supply the blank needle to the driver member from its tip.

  The driver mechanism 50a is composed of a plate-shaped driver plate, a driver member 52 incorporating a former member and a die member, and a linear shape in the process of moving the driver plate and former member from top dead center to bottom dead center. The blank needle is folded into a U shape by the former member and the die member. Then, the U-shaped needle is pressed down vigorously from the upper side to the lower side with a driver plate, and is inserted into the sheet bundle. For this reason, a drive cam connected to a drive motor (not shown) is connected to the driver plate. And it is comprised so that a driver cam may be rotationally driven with a drive motor, an accumulator spring may be made to accumulate power, and a driver plate may be moved from a top dead center to a bottom dead center with the accumulated energy.

  The clincher mechanism 50b includes a bending groove (anvil member) 53 for bending the tip of the staple needle inserted into the sheet bundle. The driver mechanism portion 50a and the clincher mechanism portion 50b are integrally attached to the unit frame, and the driver member 52 is axially supported so as to be swingable in the vertical direction of FIG. The structure of the stapling means (unit) 50 is known, for example, from Japanese Patent No. 3436022 and Japanese Patent No. 3620351.

  A plurality of the stapling means 50 described above are arranged at a distance in the sheet width direction shown in FIG. 4A (two places shown in the figure), and the stapling means 50 is bound to the processing tray 34 as shown in FIG. Arranged in Py. The exterior casing 30 is provided with opening / closing doors 54a and 54b, and the opening / closing door 54b is opened to perform needle replacement (cartridge replacement) of the staple means 50. Particularly, in the illustrated example, the stapling means 50 is disposed on the downstream side of the folding processing mechanism (folding processing position Pz) of the processing tray 34, so that it is close to the outer casing 30 and needle replacement is easy.

[Folding processing means]
A folding processing means 55 is arranged at the folding processing position Pz of the processing tray 34. The configuration of the folding processing means 55 will be described with reference to FIG. The folding processing means 55 includes a pair of folding rolls 57 (57a, 57b) and a folding blade 58. The pair of folding rolls 57 is composed of rolls 57a and 57b that are in pressure contact with each other, and each roll is formed to have the width of the maximum size sheet. Reference numeral 57S denotes a pressure contact spring. Note that at least one of the rolls 57a and 57b may be axially supported so as to be movable in the press-contact direction, and a biasing spring may be stretched over one of the rolls.

  The pair of folding rolls 57 is disposed above the processing tray 34, and a folding blade 58 having a knife edge is provided at a position facing the tray with the paper mounting surface 34a interposed therebetween. The folding blade 58 is supported by the apparatus frame so as to be able to reciprocate between a retracted position (solid line in FIG. 5) retracted from the sheet and a nip position of the pair of folding rolls 57. Blade driving means 56 is connected to the folding blade 58.

  The blade driving means 56 includes a blade driving motor MB, a transmission pinion 58p that transmits the rotation of the blade driving motor MB, and a rack 58r. The folding blade 58 is moved from the standby position (solid line in FIG. 5) to the operating position by forward and reverse rotation of the blade driving motor MB. Move to (dashed line). Therefore, the sheet bundle accumulated on the processing tray 34 is pushed out by the folding blade 58 to the nip position of the folding roll pair 57 and is folded by the roll pair.

[Stack part]
Next, the configuration of the stack part B2 will be described with reference to FIG. The post-processing unit B is disposed above the image forming unit A, the subsequent processing unit B1 is disposed on the upper right side, and the stack unit B2 is disposed on the upper left side. Then, the processing tray 34 is positioned so that the post-processing unit B1 post-processes the sheet guided in the same direction as the sheet discharge direction Sz of the image forming unit A, and the stack unit B2 has a discharge direction of the image forming unit A. A single sheet stacker 32 is positioned to accommodate sheets guided in the opposite direction.

  The stack unit B2 includes a single sheet stacker 32 that stores sheets that are not folded and a folded sheet stacker 33 that stores sheets that have been folded. In the exterior casing 30 of the post-processing unit B, a folded sheet stacker 33 is disposed above and a single sheet stacker 32 is disposed below in parallel. The single sheet stacker 32 includes a tray for stacking and storing sheets, and a tray lifting mechanism (not shown) that lifts and lowers the tray according to the stacking amount. A single sheet carry-out path 25z is provided between the single sheet stacker 32 and the paper discharge path 25 of the image forming unit A. The folded sheet stacker 33 is composed of a tray for stacking and storing sheets, and a folded sheet carry-out path 25 y is provided between the folded sheet stacker 33 and the pair of folding rolls 57 of the processing tray 34.

[Configuration of sheet carry-out path]
The configuration of the single sheet carry-out path 25z and the folded sheet carry-out path 25y will be described with reference to FIG. The single sheet carry-out path 25z is constituted by a curved path that branches from the aforementioned paper discharge path (straight path) 25x so as to be continuous with the paper discharge path 25 of the image forming unit A and guides the sheet to the single sheet stacker 32. . The single sheet carry-out path 25z guides the sheet by making a U-turn in a direction opposite to the sheet discharge direction Sz of the discharge path 25. Reference numeral 26 denotes a path switching unit that distributes and conveys the sheet sent from the image forming unit A in the direction of the processing tray 34 and the direction of the single sheet stacker 32.

  The folded sheet carry-out path 25 y guides the folded sheet sent from the folding roll pair 57 disposed on the processing tray 34 to the folded sheet stacker 33. As is apparent from FIG. 3, the single sheet carry-out path 25z and the folded sheet carry-out path 25y are both configured as curved paths, and the curvature of the folded sheet carry-out path 25y is smaller than the curvature of the single sheet carry-out path 25z. 25y is formed in a path close to a straight line. The single sheet carry-out path 25z and the folded sheet carry-out path 25y are each provided with a conveyance roller for conveying sheets (bundles) and connected to a drive motor (not shown).

  As described above, the apparatus of FIG. 1 sets the sheet discharge direction Sz to be opposite to the sheet feeding direction Sk of the image forming unit A, and the single sheet discharge direction Sa with respect to the sheet discharge direction Sz. The folded sheet discharge direction Sb is arranged in the opposite direction (see FIG. 1). As a result, the sheet moves in a zigzag manner in the apparatus, thereby concentrating the apparatus.

[Device frame]
The image forming unit A and the post-processing unit B described above are incorporated and integrated into the apparatus frame 60 as follows. The device frame structure will be described with reference to FIG. The image forming unit A and the post-processing unit B are provided with independent outer casings (10, 30). In particular, in the image forming unit A, the outer casing 10 is provided with a stacker 59 (see FIGS. 1 and 3) connected to the paper discharge path 25.

  The apparatus frame 60 is configured in a frame structure that forms a housing portion (lower mounting space) 60A for the image forming unit A and a housing portion (upper mounting space) 60B for the post-processing unit B. In the illustrated frame structure, a plurality of installation legs 61 (61 a to 61 f), reinforcing connection arms 62 (62 a, 62 b, 62 c), and a bottom plate 63 constitute a housing. The bottom plate 63 (lower mounting space) accommodates the image forming unit A, and the upper portion (upper mounting space) accommodates the post-processing unit B. The post-processing unit B is directly attached to the installation legs 61 (61a to 61f).

  The image forming unit A is fitted to positioning pins 64 (64a, 64b, 64c) formed on the bottom plate 63, and the position thereof is set (fixed). As described above, the apparatus frame 60 and the image forming unit A are positioned by the positioning members (fitting pins, steps), and the above-described discharge path 25 and the discharge path (straight path) 25x are matched (height direction and width). Direction).

  The post-processing unit B is placed and supported on the installation legs 61 (61a to 61f) of the apparatus frame 60, and the entire unit rotates around the first hinge shaft 65 shown in FIG. FIG. 7 shows the open / closed state. The post-processing unit B is supported by the apparatus frame 60 so as to be rotatable in the direction of arrow A in the figure around the first hinge shaft 65. A frame (not shown) of the post-processing unit B is placed and supported on the apparatus frame 60. A buffer member (not shown) that assists in opening and closing the first hinge shaft 65 is provided.

  That is, although not shown, the post-processing unit B is mounted and supported on the apparatus frame 60, and at the same time, is supported so as to be rotatable within a predetermined angle range around the first hinge shaft 65, and assists its opening / closing operation. A buffer member is provided. For example, the buffer member is composed of a swing arm having one end supported on the apparatus frame side and the other end supported on the unit side, and a buffer mechanism such as an urging spring (or air spring) that reduces the load on the post-processing unit B. ing.

  Therefore, first locking means 66 is provided between the apparatus frame 60 and the post-processing unit B, and the post-processing unit B rotates to the state shown in FIG. 7 by releasing the lock of the first locking means 66. . Since this first locking means 66 is already widely known and will not be described in detail, an opening / closing lever 66a having a locking claw is provided on one side between the apparatus frame 60 and the post-processing unit B, and this locking is provided on the other side. An engaging claw 66b that engages with the claw is provided. When the user operates the opening / closing lever 66a, the engagement is released and the post-processing unit B can be rotated.

  Accordingly, when the post-processing unit B is rotated to the state shown in FIG. 7, the upper part of the image forming unit A accommodated in the apparatus frame 60 is opened as shown in FIG. Therefore, for example, when a sheet jam occurs in the sheet discharge path 25 of the image forming unit A, the jammed sheet J1 in the sheet discharge path 25 can be removed by opening a part of the outer casing 10. Therefore, the exterior casing 10 of the image forming unit A can be opened and closed so that a part thereof opens the paper discharge path 25.

  In the post-processing unit B, the processing tray 34, the single sheet carry-out path 25z, the folded sheet carry-out path 25y, the single sheet stacker 32, and the folded sheet stacker 33 are provided as described above. Therefore, when a problem such as a sheet jam occurs in the processing tray 34, the entire unit is rotated to the state shown in FIG.

  In this state, the moving frame 41 having the paper placement surface 34 a of the processing tray 34 is configured to be rotatable by the second hinge shaft 47. Therefore, as shown in FIG. 7, the jammed sheet J2 jammed on the processing tray 34 can be taken out by swinging the moving frame 41 (paper table) about the second hinge shaft 47. The opening / closing operation of the moving frame 41 is also performed by operating a lock means (not shown). This locking means may adopt the same structure as the first locking means 66 described above.

  Further, the post-processing unit B has the following configuration in order to remove the sheet jam generated in the single sheet carry-out path 25z and the folded sheet carry-out path 25y. FIG. 8A shows a state where the jammed sheet J3 generated in the folded sheet carry-out path 25y is removed. The post-processing unit B is configured so that a part of the path guide (upper conveyance guide) can be rotated by the third hinge shaft 67 in order to open the folded sheet carry-out path 25y, and sheet jam occurs in the folded sheet carry-out path 25y. When this is done, a part of the outer casing 30 is rotated about the third hinge shaft 67 to the state shown in FIG. In this state, the jammed sheet J3 in the folded sheet carry-out path 25y can be taken out.

  FIG. 8B shows a state in which the jammed sheet J4 generated on the single sheet carry-out path 25z is removed. Similarly to the above, the post-processing unit B is configured to be able to turn a part of the path guide (upper conveyance guide) of the single sheet carry-out path 25z around the third hinge shaft 67. Then, by rotating a part of the post-processing unit B around the third hinge shaft 67 in the state shown in the figure, the jam sheet J4 of the single sheet carry-out path 25z can be taken out.

  In addition, the opening / closing part of the upper conveyance guide of the folded sheet carrying path 25y shown in FIG. 8A is provided with the second locking means 68 similarly to the first locking means 66 described above, and similarly, the single sheet carrying path 25z. The third locking means 69 is provided at the opening / closing part of the upper conveyance guide. As shown in FIG. 6, when the first locking means 66 is operated (unlocked), the entire unit rotates around the first hinge shaft 65 (state shown in FIG. 7). Further, when the second locking means 68 is unlocked, a part of the unit is rotated so as to open the folded sheet carry-out path 25y (state shown in FIG. 8A). Similarly, when the third locking means 69 is unlocked, a part of the unit is rotated so as to open the single sheet carry-out path 25z (state shown in FIG. 8B).

  In the illustrated apparatus, the single sheet carry-out path 25z of the post-processing unit B is arranged above the paper discharge path 25 of the image forming unit A, and the folded sheet carry-out path 25y is further arranged in parallel above and below the post-process. The unit B is configured to be rotated by the first hinge shaft 65 and the third hinge shaft 67 to open the path. Thus, for example, the folded sheet carry-out path 25y located at the top is opened, then the single sheet carry-out path 25z is opened, and finally the paper discharge path 25 of the image forming unit A is opened. And can be easily removed.

  Note that the sheet jam in the image forming unit A displays the jam position in the same manner as the jam detection by the sheet sensor arranged in the path. Similarly, the sheet jam in the post-processing unit B displays the jam position in the same way as the jam detection by the sheet sensor in the path (processing tray, single sheet carry-out path, folded sheet carry-out path, etc.).

[Control configuration]
The control configuration of the apparatus shown in FIG. 1 will be described with reference to FIG. The image forming unit A is provided with a control CPU 70, and a ROM 71 storing an operation program and a RAM 72 storing control data are connected to the control CPU 70. The control CPU 70 is provided with a paper feed control unit 73, an image formation control unit 74, and a paper discharge control unit 75. Along with this, an input means 76 and a controller panel 78 having a display means 77 are connected to the control CPU 70. Therefore, the image forming conditions are set by the mode setting means 79 provided in the control CPU 70.

  The mode setting unit 79 is configured to set a “single-sided printing mode” and a “double-sided printing mode” at the same time as setting various image forming conditions (for example, color, monochrome, and reduction). In the “single-sided printing mode”, an image is formed on one side of the sheet sent from the paper feeding unit A 1 and is carried out from the paper discharge path 25. In the “double-sided printing mode”, an image is formed on one side of the sheet sent from the paper feeding unit A 1, and then the sheet is turned upside down to form an image on the back side and carried out from the paper discharge path 25.

  The control CPU 70 is configured to select a “print-out mode” and a “post-processing mode”. In the “print-out mode”, the image-formed sheet is stored in the single sheet stacker 32 without finishing. Further, in the “post-processing mode”, the sheets on which the images have been formed are aligned and collected, and after being bound, are folded and stored in the folded sheet stacker 33.

  A post-processing control CPU 80 is provided in the post-processing unit B, and a ROM 81 that stores a control program and a RAM 82 that stores control data are connected to the post-processing unit B. The control CPU 80 receives sheet size information, a paper discharge instruction signal, and a mode setting command for the post-processing mode and the printout mode from the control unit of the image forming unit A.

  The control CPU 80 includes a paper discharge control unit 83 that controls the rotation of the conveyance roller of the single sheet carry-out path 25z, an accumulation control unit 84 that aligns and stacks sheets on the processing tray 34, a binding processing control unit 85, and a folding processing control unit. 86 and a paper discharge control unit 87 that controls the rotation of the conveyance roller in the folded sheet carry-out path 25y.

[Description of operation]
The control CPU 70 of the image forming unit A described above executes the following image forming operation in accordance with the image forming program stored in the ROM 71. Similarly, the control CPU 80 of the above-described post-processing unit B executes the following post-processing operation according to the post-processing program stored in the ROM 81.

"Image formation operation"
When the “single-sided printing mode” is selected by the mode setting unit 79, the control CPU 70 operates the sheet of the set size from the sheet feeding cassette 11 and feeds it to the registration roller 14. Before and after this, the control CPU 70 forms an image on the intermediate transfer belt 21 according to predetermined image data. The image data is stored in a data storage unit (not shown) or transferred from an external device connected to the image forming unit A.

  Therefore, the control CPU 70 transfers the toner image formed on the intermediate transfer belt 21 to the sheet sent from the registration roller 14 by the transfer unit 15 and fixes it by the fixing device 24 on the downstream side thereof. Thereafter, the control CPU 70 sends the image-formed sheet to the paper discharge path 25 and transfers it to a post-processing unit B described later.

  When the “double-sided printing mode” is selected by the mode setting unit 79, the control CPU 70 executes the above-described operation to form an image on one side of the sheet and send it to the paper discharge path 25. At this time, the control CPU 70 causes the post-processing unit B to execute the following operation. The control CPU 80 of the post-processing unit B shifts the guide flapper 25f to the solid line position in FIG. 3 and the path switching means 26 to the broken line position based on the detection signal of the sensor Se1 (see FIG. 3) when the leading edge of the sheet reaches the paper discharge path 25. To do. As a result, the sheet sent to the paper discharge path 25 is sent from the paper discharge path 25 to a paper discharge path (straight path) 25x.

  Simultaneously with this path switching control, when the leading edge of the sheet is carried into the processing tray 34 from the straight path 25x, the control CPU 80 moves the lifting roller 36 from the standby position to the operating position and simultaneously rotates this roller. Then, the sheet carried into the processing tray 34 is sent to the downstream side along the processing tray 34 by the rotation of the lifting roller 36.

  Next, when the control CPU 80 detects the trailing edge of the sheet by the sensor Se1, at the timing when the trailing edge of the sheet passes through the guide flapper 25f, the control CPU 80 moves the flapper 25f to the position of the broken line in FIG. Rotate. Then, the sheet reverses the conveyance direction and moves backward (switchback movement) to the paper discharge path 25. With this switchback movement, the sheet is sent to the circulation path 27.

  Therefore, the control CPU 70 of the image forming unit A sends the sheet sent to the circulation path 27 to the registration roller 14 by inverting the front and back through this path. Before and after this, the control CPU 70 forms a back image on the intermediate transfer belt 21, forms an image on the back surface of the sheet by the transfer unit 15, and carries it out to the paper discharge path 25.

"Post-processing operation; printout mode"
The control CPU 80 of the post-processing unit B receives the sheet leading edge detection signal from the sensor Se1 of the image forming unit A when the mode setting unit 79 is set to “print-out mode”, and turns the path switching unit 26 into a solid line in FIG. Shift to state. At the same time, the control CPU 80 rotates the conveyance roller disposed in the single sheet carry-out path 25z. With this operation, the sheet on which the image is formed by the image forming unit A is stored in the single sheet stacker 32 through the paper discharge path 25 and the single sheet carry-out path 25z.

“Post-processing operation; Post-processing mode”
The control CPU 80 guides the sheet sent to the paper discharge path 25 of the image forming unit A to the processing tray 34 when the mode setting unit 79 sets the “post-processing mode”. In this operation, the guide flapper 25f is shifted to the solid line position in FIG. 3 and the path switching means 26 is shifted to the broken line position in accordance with the tip detection signal of the sensor Se1. By this operation, the sheet is sent from the paper discharge path 25 to the straight path 25x and is sent onto the processing tray 34.

  Therefore, the control CPU 80 moves the roller from the standby position to the operating position within a predetermined time after the leading edge detection signal of the sensor Se1 has elapsed and the sheet leading edge is expected to reach the lift roller 36. At the same time, the elevating roller 36 is rotated in the sheet conveying direction (counterclockwise in FIG. 3) to position the rear end of the sheet on the regulating member 37, and then the elevating roller 26 is raised to the standby position.

  Then, the control CPU 80 controls the side regulating plates 38R and 38L after the sheet trailing edge is carried onto the processing tray 34, and aligns the width of the sheet that has entered the processing tray. By repeating this operation, sheets are stacked on the processing tray 34 (sheet stacking operation).

  Next, when receiving a job end signal from the image forming unit A, the control CPU 80 executes “sheet bundle position moving operation” and “binding processing operation”. In response to the job end signal, the control CPU 80 moves the sheet bundle accumulated at the accumulation reference position Px on the processing tray 34 from the reference position Px to the binding position Py. In this sheet bundle movement, the trailing edge transfer means 46A and the leading edge transfer means 46B are simultaneously moved by the same amount. In this case, when the stacking reference position Px and the binding position Py are the same position (for example, when the rear end of the sheet is aligned with the reference position, the center of the sheet is positioned at the binding position Py), the sheet bundle is moved. Instead, the process proceeds to the next binding processing operation.

  The control CPU 80 moves the sheet bundle from the stacking reference position Px to the binding position Py so that the sheet center (1/2 position in the transport direction) is positioned at the binding position Py. Then, the control CPU 80 issues a staple operation start instruction signal to the binding processing means (staple means) 50. With this signal, the stapling means 50 starts a drive motor built in the unit and rotates the stapling operation cam. By this cam action, the staple needle is bent into a U shape and inserted into the sheet bundle. The tip of the needle is then bent by an anvil and bound. The stapling means 50 are arranged at two places in the sheet width direction, and operate simultaneously or sequentially.

  Next, when receiving an operation end signal from the stapling means 50, the control CPU 80 moves the sheet bundle from the binding position Py to the folding processing position Pz. Since the folding processing position Pz is arranged at a distance downstream from the binding position Py, the sheet bundle on the processing tray advances from the stacking reference position Px to the binding position Py, and after the binding processing, the folding processing position Pz. Will retreat to.

  In this case, the sheet bundle is moved backward by the same amount of the trailing edge transfer means 46A and the leading edge transfer means 46B as described above. Therefore, the control CPU 80 performs folding processing on the sheet bundle positioned at the folding processing position Pz. In this folding processing operation, the folding roll pair 57 is rotated in the direction of the arrow in FIG. 5, and at the same time, the folding blade 58 is moved from the standby position to the operating position.

  The sheet bundle stapled at the center by the operation of the folding blade 58 and the folding roll pair 57 is folded at the folding position as shown in FIG. Therefore, the control CPU 80 rotates the conveyance roller of the folded sheet carry-out path 25y in the paper discharge direction before and after the folding processing operation. Then, the sheet bundle sent out by the pair of folding rolls 57 is guided to the folded sheet stacker 33 along the folded sheet carry-out path 25y and is accommodated therein.

A Image forming unit B Post-processing unit C Image forming apparatus 10 Exterior casing 14 Registration roller 15 Transfer section 21 Intermediate transfer belt 25 Paper discharge path 25x Paper discharge path (straight path)
25f Guide flapper 25z Single sheet carry-out path 25y Folded sheet carry-out path 26 Path switching means 30 Exterior casing 32 Single sheet stacker 33 Folded sheet stacker 34 Processing tray 36 Lifting roller 37 Restricting member 41 Moving frame 46 Sheet bundle conveying means 46A Rear end conveying means 46B Tip transfer means 47 Second hinge shaft 50 Binding processing means (staple means)
55 Folding processing means 60 Device frame 60A Image forming unit housing (lower mounting space)
60B Aftertreatment unit housing (upper mounting space)
61 Installation legs (61a-61f)
62 Reinforced connecting arms (62a, 62b, 62c)
63 Bottom plate 64 Positioning pin (64a, 64b, 64c)
65 First hinge shaft 66 First locking means 67 Third hinge shaft 68 Second locking means 69 Third locking means Sk Sheet feeding direction Sy Sheet feeding direction Sz Sheet discharging direction Sa Single sheet discharging direction Sb Folded sheet discharge Paper direction

Claims (7)

An image forming unit for forming an image on a sheet;
A processing tray for collecting sheets sent from the image forming unit to form a sheet bundle ;
Folding processing means for performing a folding process on the sheet bundle on the processing tray;
A single sheet stack tray for storing the sheets sent from the image forming unit without folding,
And folding the sheet stack tray for containing the sheet bundle processed folding that transmitted from the processing tray,
A discharge path for selectively guiding the sheet fed from the image forming unit to the single sheet stack tray and the processing tray,
Path switching means arranged in the paper discharge path;
A reversing path again sent to the image forming unit by reversing the sheets fed from the image forming unit,
With
The paper discharge path is
A substantially linear path for guiding the processing tray the sheets fed from the image forming unit to transfer in the same direction, the sheet fed from the image forming unit to transfer in the opposite direction by the U-turn the single sheets It is configured to branch in two directions with a curved path guided to the stack tray,
Before Symbol reverse path, after loading the tip of the sheet fed from the image forming section to the processing tray, that is configured to Drying in the image forming unit again by reversing the conveying direction An image forming apparatus. The image forming apparatus according to claim 1, further comprising a binding processing unit that performs a binding process on a central portion of the sheet bundle of the processing tray. The processing tray and the single sheet stack tray are arranged in parallel above the image forming unit,
The image forming apparatus according to claim 1, wherein the folded sheet stack tray is disposed above the single sheet stack tray. The image forming unit is provided with a sheet feeding unit that sequentially supplies sheets,
A sheet feeding direction in which the sheet is fed from the sheet feeding unit to the image forming unit, a sheet discharging direction in which the sheet is carried out from the image forming unit to the processing tray, and a sheet from the image forming unit to the single sheet stack tray. and a single sheet discharge direction for unloading a, a folded sheet paper discharge direction for unloading the folded sheets from the processing tray to the folded sheet stack tray,
The relative sheet feeding direction, the said are sheet discharging direction is set in the opposite direction, with respect to the sheet discharging direction, the said single sheet discharging direction in the opposite direction with the folded sheet discharging direction, The image forming apparatus according to claim 1, wherein each is set. Wherein the processing tray is vertically movable disposed between the conveying rollers to transport the sheet in the sheet discharge direction and a retracted position retracted and an operating position of the seat engage on the processing tray,
The image forming apparatus according to claim 1, wherein the transport roller is positioned at a standby position when a leading end of a sheet sent from the image forming unit is carried into the processing tray. The processing tray includes a paper loading surface inclined at a predetermined angle with respect to a horizontal direction,
2. The image forming apparatus according to claim 1, wherein a sheet end regulating means for regulating a trailing end of the sheet sliding down by its own weight is disposed on the paper mounting surface. In the processing tray,
Saddle-stitching stapling means for binding the central portion of the sheet bundle that has been gathered together;
The folding processing means for folding the saddle stitched folded sheet;
Is placed,
The saddle stitching stapling means and the folding processing means are:
2. The image according to claim 1, wherein the folding process is positioned upstream and the binding process position is positioned downstream with respect to a sheet discharge direction in which the sheet is carried out to the processing tray. Forming equipment.

Images