JP2020132334A - Sheet stacking device - Google Patents

Abstract

To provide a sheet stacking device in which a paper jamming occurrence of a sheet at a position affected by a liftable stacking tray is suppressed, and the height of the stacking tray is controlled based on a recovery operation after the paper jamming occurrence and an occurrence tendency of the paper jamming.SOLUTION: In a recovery operation after a paper jamming occurrence related to the height of a stacking tray, the stacking tray is moved to a position where a paper jamming due to the height does not recur, and the processing is resumed. The number of stacked sheets at the time of the paper jamming occurrence is recorded together with the information about the processing content, the size, etc. at the time of the paper jamming occurrence. This information is reflected on the height control of the stacking tray so that a paper jamming is not caused under the same condition, and thereby paper jamming is prevented.SELECTED DRAWING: Figure 1

Description

The present invention is mainly related to a sheet loading device that forms a sheet bundle from sheets discharged from an image forming device and loads them on a predetermined loading tray, and relates to suppressing the occurrence of paper jams in the transport path of the discharged sheets. ..

Conventionally, in a sheet post-processing device that performs a predetermined post-treatment on a sheet discharged from an image forming device or the like, a loading tray for finally loading the post-processed sheet is configured to be able to move up and down. It is known that the top surface of a sheet loaded on a loading tray is detected by a sensor or the like to control the position of the loading tray.

In Patent Document 1, the position of the uppermost surface of the Z-folded sheet 14 to be loaded on the stack tray (29) configured to be able to move up and down is detected by the paper surface detecting member (45), and the position of the paper surface is fixed. The stack tray (29) is controlled so as to keep it at (FIG. 11 of the same document). By keeping the height of the paper surface on the loading tray constant in this way, the alignment is improved and the paper jam (JAM) is suppressed.

Further, there is known a sheet post-processing device in which a part of the paper on the processing tray is supported by the loading tray and post-processing is performed with the paper straddling the processing tray and the loading tray. Therefore, maintaining an appropriate paper surface on the loading tray is important for alignment on the processing tray and for suppressing paper jams when loading paper into the processing tray.

Japanese Unexamined Patent Publication No. 2005-001779

In the post-processing device that detects the position of the paper surface on the loading tray and controls the position of the loading tray as in the above-mentioned prior art document, in recent years, paper types such as recycled paper having a large degree of curling are included. Due to the need to support a wide range of paper types and the support for folded paper, there are increasing cases where the position of the paper surface on the loading tray cannot be accurately detected by the detection means.

For example, the discrepancy between the height detection due to the degree of curling and the degree of folding processing and the actual loading height increases as the number of loaded sheets increases, and a paper jam tends to occur at a specific number of loaded sheets on the loading tray. For example, in the case of A4 size paper of a specific brand having a large curl tendency, a paper jam occurs every time about 200 sheets are passed.

In such a case, the paper jam is always repeated at a predetermined timing, which causes a decrease in productivity and a burden on the user such as clearing / recovery work when a paper jam occurs. Therefore, it is desired to automatically recognize a paper jam having a specific tendency and reduce the occurrence of the paper jam as much as possible.

In order to solve the above problems, in the present invention, a sheet transporting means for transporting sheets discharged from an image forming apparatus, a loading tray for loading sheets transported by the sheet transporting means, and the loading tray or the loading. The tray height detecting means for detecting the height of the uppermost sheet loaded on the tray, the tray raising and lowering means for raising and lowering the loading tray based on the detection result of the tray height detecting means, and the sheet transporting means. The sheet is not conveyed to the loading tray. When a paper jam detecting means for detecting the occurrence of a paper jam and the paper jam detecting means detect a paper jam, the sheet is transferred from the sheet conveying means to the loading tray after the paper jam is cleared. A configuration is adopted that includes a control means for controlling the tray elevating means so as to move the loading tray to a position lower than the position where the paper jam is detected by the paper jam detecting means before carrying.

Alternatively, the number of sheets recognizing means for recognizing the number of sheets loaded on the loading tray and the number of sheets recognized by the sheet number recognizing means when a paper jam is detected by the paper jam detecting means in a predetermined job. The control means includes a recording means for recording the number of sheets, and the control means has a job different from the predetermined job, before the number of sheets recognized by the sheet number recognition means becomes the number of sheets recorded in the recording means. In addition, a configuration is adopted in which the tray elevating means is controlled so as to move the loading tray to a position lower than the position where the paper jam is detected by the paper jam detecting means in the predetermined job.

Alternatively, the recording means further includes a size recognizing means for recognizing the size of the sheet loaded on the loading tray, and the recording means recognizes the size when a paper jam is detected by the paper jam detecting means in the predetermined job. The size of the sheet recognized by the means is further recorded, and the control means records a paper jam of the same size as the sheet conveyed by the sheet conveying means in the recording means in a job different from the predetermined job. If the number of sheets is recognized by the size recognition means in the predetermined job, the size of the sheet is recognized by the size recognition means before the number of sheets recognized by the sheet number recognition means becomes the number of sheets recorded in the recording means. A configuration is adopted in which the tray elevating means is controlled so as to move the loading tray to a position lower than the position where the paper jam is detected by the paper jam detecting means.

The cause of the paper jam detected by the paper jam detection sensor placed immediately before the loading tray or the processing tray is the height detection of the loading tray when dealing with curled paper or folded paper as described above. Due to the error of. According to the above configuration, when a paper jam is detected by the paper jam detection sensor placed immediately before the loading tray or the processing tray, it can be determined that the situation will be adjusted according to the number of loaded sheets recorded in the recording means and when restarting. In addition, by controlling the height of the loading tray to a low position, it is possible to suppress the occurrence of paper jams based on the tendency of paper jams to occur, which is an excellent effect.

It is a front view which shows the outline of the whole image formation system in embodiment of this invention. It is a perspective view which shows the whole structure of the post-processing unit in this invention. It is a side sectional view which shows the apparatus structure of the post-processing unit in this invention. It is a top sectional view which shows the apparatus structure of the post-processing unit in this invention. The types of binding processing in the post-processing unit are shown. (A) is multi-binding that binds two or more positions, (b) is right corner binding that binds one position on the right side, and (c) is. It is explanatory drawing which shows each of the left corner binding which binds the position of one place on the left side. It is sectional drawing which shows the stapler unit which performs the binding processing of a post-processing unit. It is sectional drawing which shows the loading tray part of a post-processing unit. It is a block diagram which shows the control structure in an image formation system. An explanatory view showing a state of sheet transfer in the post-processing unit, (a) showing a state in which the sheet is stored in the processing tray, and (b) showing a state in which the next sheet is conveyed along the upper part of the preceding sheet. is there. The state in which the curl sheet is loaded in the post-processing unit is shown, (a) shows the state in which a paper ejection failure occurs when the curl sheet is loaded, and (b) shows the state in which the loading tray is lowered when the curl sheet is loaded. It is explanatory drawing which shows each. It is explanatory drawing which showed the post-processing unit of Patent Document 1. FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. The configuration shown below is merely an example, and for example, a person skilled in the art can appropriately change the detailed configuration without departing from the spirit of the present invention. Further, the numerical values taken up in the present embodiment are reference numerical values and do not limit the present invention.

In the following, a sheet bundle binding processing mechanism for binding a sheet bundle in which an image is formed and the parts are aligned and accumulated in an image forming system or the like will be illustrated. For example, the image forming system shown in FIG. 1 is composed of an image forming unit A, an image reading unit C, and a post-processing unit B. Then, the original image is read by the image reading unit C, and the image forming unit A forms an image on the sheet based on the image data. Then, the image-formed sheets are aligned and accumulated by the post-processing unit B (sheet bundling processing device; the same applies hereinafter), subjected to the binding processing, and stored in the loading tray 25 on the downstream side.

The post-processing unit B is built as a unit in the paper ejection space (stack tray space) 15 formed in the housing of the image forming unit A, and the image forming sheets sent to the paper ejection port 16 are aligned and accumulated on the processing tray. The inner finisher structure provided with a post-processing mechanism for storing in the loading tray 25 arranged on the downstream side after the binding process is shown. The present invention is not limited to this, and it is also possible to configure the image forming unit A, the image reading unit C, and the post-processing unit B in an independent stand-alone structure, and to systematize the devices by connecting them with a network cable.

[Sheet binding processing device (post-processing unit)]
FIG. 2 shows a perspective configuration of the post-processing unit B, and FIG. 3 shows a cross-sectional configuration thereof. As shown in each of these figures, the post-processing unit B includes an apparatus housing 20, a sheet carry-in path 22 (first paper discharge path; the same applies hereinafter) arranged in this housing, and a downstream side of the path paper discharge port 23. A processing tray 24 arranged in the housing tray 24 and a loading tray 25 arranged further downstream thereof are provided. The carry-in inlet (first carry-in entrance) 21a of the sheet carry-in route 22 is connected to the paper discharge port (first paper discharge port) 16a of the image forming unit A, and guides the image-formed sheet to the processing tray 24. After being post-processed, it is configured to be stored in the loading tray 25 on the downstream side. Further, in the device housing 20, a second paper discharge path 68 is arranged above the sheet carry-in path 22, and the path carry-in port 21b is connected to the paper discharge port (second paper discharge port) 16b of the image forming unit A. ..

The sheets guided to the sheet carry-in route (first paper discharge route) 22 are accumulated in the processing tray 24 on the downstream side from the route paper discharge port 23, and are stored in the loading tray 25 after being bound on this tray. To. Further, a sheet that cannot be processed by the first paper ejection route 22 or is processed in parallel is guided to the second paper ejection route 68. The device shown is (1) a sheet that overflows from the first output path 22, (2) an interrupt-printed sheet, and (3) a sheet that is switched back for double-sided printing in the second output path 68. Etc. are stored or temporarily held.

[Device housing]
The device housing 20 is composed of a device frame 20a and an exterior casing 20b, and the device frame 20a is composed of a frame structure that supports each mechanical unit (path mechanism, tray mechanism, transport mechanism, etc.) described later. In the illustrated configuration, a binding mechanism, a transport mechanism, a tray mechanism, and a drive mechanism are arranged on a pair of left and right side frame frames (not shown) facing each other, and have a monocoque structure integrated with an exterior casing 20b. The outer casing 20b has, for example, a monocoque structure in which the left and right side frame frames 20c and 20d and the stay frame (bottom frame frame 20e described later) connecting the both side frame frames are integrated by molding resin or the like. (On the front side of the device) is exposed so that it can be operated from the outside.

That is, the outer periphery of the frame frame is covered with the outer casing 20b, and is incorporated in the paper ejection space 15 of the image forming unit A described later. In that state, the outer case on the front side of the device is exposed so that it can be operated from the outside. The front side of the exterior casing 20b is equipped with a staple cartridge mounting opening 28, a manual feed set portion (insertion portion) 29, and a manual operation button 30 (for example, a switch having a built-in indicator lamp), which will be described later.

[Structure of the first paper discharge route]
A first paper ejection path 22 and a second paper ejection path 68 are vertically arranged in the device housing 20. The first paper discharge route (sheet carry-in route; the same applies hereinafter) 22 is arranged below the second paper discharge route (sheet placement guide; the same applies hereinafter) 68 as shown in FIG. 3, and both routes are up and down in the paper discharge direction. It is arranged almost parallel to. The first paper discharge path 22 includes a carry-in inlet (first carry-in entrance) 21a connected to the first paper discharge port 16a of the image forming unit A, and is linearly arranged horizontally so as to cross the device housing 20. It consists of routes.

[Sheet transport means]
The first paper discharge path 22 is formed of an appropriate paper guide (plate) 22a, and has a built-in transport roller pair for transporting the sheet. In the one shown in FIG. 3, a carry-in roller pair 31 is arranged near the first carry-in inlet 21a as a sheet transporting means, and a paper discharge roller pair 32 is arranged near the paper discharge port 23. Further, a sheet sensor Se1 for detecting the front end and / or the rear end of the sheet is arranged in the first paper ejection path 22. The above-mentioned carry-in roller pair 31 and paper discharge roller pair 32 are connected to the same drive motor M1 (: FIG. 8, hereinafter referred to as a transfer motor), and transfer the sheet at the same peripheral speed.

[Structure of the second paper discharge route]
The second paper ejection path 68 has a carry-in inlet (second carry-in inlet) 21b which is arranged above the first paper discharge path 22 and is connected to the second paper discharge port 16b of the image forming unit A. As described above, the second output path 68 is used for overflow, accommodating the interrupt printing sheet, and temporarily holding the sheet to be sent to the duplex path. Since a plurality of sheets can be loaded on the second paper ejection path 68, a paper ejection mechanism such as a roller belt is not provided. Further, the second paper discharge path 68 is provided with a mechanism for removing the sheet jam of the first paper discharge path 22 arranged below.

The processing tray 24 is provided with a sheet loading means 35 for loading sheets, a sheet regulating means 40 for accumulating the loading sheets in a bundle, and a matching means 45. Along with this, the processing tray 24 is provided with a staple binding means (26: first binding means) for staple binding the sheet bundle and a needleless binding means (27: second binding means) for binding the sheet bundle without a needle. ing. Each configuration will be described in detail below.

[Processing tray]
As shown in FIG. 3, a processing tray 24 is arranged on the paper ejection port 23 of the first paper ejection path 22 so as to form a step d on the downstream side thereof. Since the processing tray 24 stacks the sheets sent from the paper ejection port 23 upward and accumulates them in a bundle, the processing tray 24 includes a paper mounting surface 24a that supports at least a part of the sheets. The illustrated one adopts a structure (bridge support structure) in which the seat front end side is supported by the loading tray 25 described later and the seat rear end side is supported by the processing tray 24. As a result, the tray size can be reduced.

The processing tray 24 collects the sheets sent from the paper ejection port 23 in a bundle shape, aligns the sheets with a predetermined posture, performs a binding process, and carries out the processed sheet bundle to the loading tray 25 on the downstream side. It is configured in. Therefore, the processing tray 24 incorporates a sheet loading mechanism 35, a sheet matching mechanism 45, a binding processing mechanism (26, 27), and a sheet bundle unloading mechanism 60.

[Sheet loading mechanism (sheet loading means)]
A processing tray 24 is arranged in the above-mentioned paper ejection port 23 so as to form a step d. A sheet loading means for smoothly transporting the sheet in the correct posture on the processing tray is required. The illustrated sheet loading means (friction rotating body) is composed of a paddle rotating body 36 that moves up and down, and when the rear end of the sheet is carried out onto the tray from the paper ejection port 23, the paddle rotating body 36 ejects the sheet in the opposite direction of paper ejection ( It is transferred to the right direction in FIG. 3) and abutted against the sheet edge regulating means 40 described later for alignment (positioning).

[Paper jam detection means]
A sheet sensor Se2 for detecting the front end and / or the rear end of the sheet is arranged on the first transport path 22 in the vicinity of the upstream side of the paper ejection port 23. The sheet sensor Se2 is also used to monitor whether or not the sheet is correctly transported from the first transport path 22 to the paper ejection port 23, and when the sheet stays on the sheet sensor Se2 for a predetermined time or longer, the sheet is seated. It is detected as a jam (paper jam) that interrupts the transportation of the paper.

Further, the paper ejection port 23 is provided with an elevating arm 37 oscillatingly supported by a support shaft 37x on the device frame 20a, and the paddle rotating body 36 is rotatably supported at the tip of the elevating arm. Has been done.

As shown in FIG. 4, the paddle rotating bodies 36 are arranged symmetrically in pairs at a predetermined distance from the seat center (center reference Sx). In addition, a total of three paddle rotating bodies may be arranged on the seat center and both sides thereof, or one paddle rotating body may be arranged on the seat center.

The paddle rotating body 36 can be composed of a flexible rotating body such as a rubber plate-shaped member or a plastic blade member. As an alternative member of the paddle rotating body 36, a friction rotating member such as a roller body or a belt body can be used as the sheet carrying means 35. The paddle rotating body 36 is controlled so that, for example, the rear end of the sheet is carried out from the paper ejection port 23 and then descends from the upper standby position Wp to the lower operating position Ap. However, the following elevating mechanism may be adopted. For example, when the tip of the sheet is carried out from the paper ejection port 23, an appropriate friction rotating body is lowered from the standby position to the operating position, and at the same time, the sheet is rotated in the paper ejection direction, and the rear end of the sheet is carried out from the paper ejection port 23. At the timing, this rotating body is rotated in the opposite direction to the paper ejection. As a result, the sheet carried out from the paper ejection port 23 can be transferred to a predetermined position on the processing tray 24 at high speed and without skewing.

[Scraping rotating body (scraping transport means)]
When the sheet is conveyed to a predetermined position on the processing tray 24 by the sheet loading mechanism 35 (paddle rotating body) arranged in the paper ejection port 23, the sheet tip is moved to the downstream side due to the influence of a curled sheet, a skewed sheet, or the like. A scraping transport means 33 for guiding to the regulation stopper 40 of the above is required.

The device shown is a scraping rotating body (scraping transporting means) that applies a feeding force to the regulating member side of the top sheet of the sheet loaded on the upstream side of the sheet edge regulating stopper 40 described later below the paper ejection roller pair 32. ) 33 is arranged. In the figure shown, a ring-shaped belt member 34 (hereinafter referred to as “scraping belt”) is arranged above the tip of the processing tray 24, and the scraping belt member 34 engages with the top sheet on the paper mounting surface. It rotates in the direction of transporting the sheet to the regulating member side.

The scraping belt 34 is configured to move up and down above the top sheet on the tray by a belt shift motor M5 (FIG. 8: hereinafter sometimes referred to as a knurled elevating motor) (details of the elevating mechanism are omitted). .. Then, at the timing when the tip of the seat enters between the surface of the belt and the top seat, the scraping belt 34 descends and engages with the carry-in seat. Further, the scraping belt 34 controls the knurled elevating motor M5 so as to be separated from the uppermost sheet and stand by upward when being transferred from the processing tray 24 to the loading tray 25 on the downstream side by the sheet bundle unloading means 60 described later.

[Sheet alignment mechanism]
A sheet matching mechanism 45 for positioning the carried-in sheet at a predetermined position (processing position) is arranged on the processing tray 24. The illustrated sheet matching mechanism 45 is a sheet edge regulating means for position-regulating the end surface (either the front end surface or the rear end surface) of the sheet sent from the output port 23 in the paper ejection direction and the paper ejection orthogonal direction (sheet side direction). It is composed of "side matching means 45" for aligning the widths. Hereinafter, they will be described in this order.

[Sheet edge regulation means]
The sheet edge regulating means (40) is composed of a rear edge regulating member 41 that abuts and regulates the trailing edge in the paper ejection direction. The rear end regulating member 41 includes a regulating surface 41a that abuts and regulates the rear end edge of the sheet carried in along the paper loading surface 24a on the processing tray in the paper ejection direction, and is a sheet fed by the scraping transport means. Hit the trailing edge and stop.

In the rear end regulating member 41, the stapler unit moves along the rear end of the sheet (in the direction orthogonal to the paper discharge) when multi-binding by the binding processing mechanism (26: stapler means) described later. In order not to interfere with the movement of the unit, (1) a mechanism is adopted to move the rear end regulating member into and out of the movement path (movement locus) of the binding unit, and (2) the position is moved integrally with the binding unit. (3) As a rear end regulating member, for example, a channel-shaped bent piece is provided inside the binding space composed of the head of the binding unit and the anvil. In the case of the present embodiment, the rear end regulating member 41 is composed of a plate-shaped bending member having a U-shaped cross section (channel shape) in which the rear end regulating member 41 is arranged in the binding space of the staple binding means (26). Then, the first member 41A is arranged in the seat center with the minimum size sheet as a reference, and the second and third members 41B and 41C are arranged on the left and right at a distance from the first member 41A (FIG. 4). This makes it possible to move the staple binding unit (26) in the sheet width direction.

"Side alignment means"
The processing tray 24 is provided with a matching means 45 (hereinafter referred to as “side matching member”) for positioning the sheet abutting on the rear end regulating member 41 in the paper ejection orthogonal direction (sheet width direction) (FIG. 4). ..

The configuration of the side matching member 45 differs depending on whether sheets of different sizes are aligned on the processing tray based on the center reference or one side reference. In the apparatus shown in FIG. 4, sheets of different sizes are ejected from the paper ejection port 23 based on the center reference, and the sheets are aligned on the processing tray based on the center reference. Then, according to the binding process, the sheet bundles aligned in a bundle shape based on the center reference are bound by offsetting a predetermined amount of sheet bundles to the binding positions Ma1 and Ma2 in the matching posture when multi-binding and in the left-right direction when binding left and right corners. The stapler binding unit (26) binds the positions Cp1 and Cp2.

Therefore, the matching means 45 projects side matching members 46 (46F, 46R) having a regulation surface 46x that protrudes upward from the paper mounting surface 24a of the processing tray and engages with the side edge of the sheet so as to face each other in pairs on the left and right sides. Place in. Then, the pair of left and right side matching members 46 are arranged on the processing tray 24 so as to be reciprocating with a predetermined stroke. This stroke is set by the size difference between the maximum size sheet and the minimum size sheet and the offset amount for moving the position (offset transfer) of the sheet bundle after matching in either the left or right direction. The movement strokes of the left and right side matching members 46F and 46R are set by the movement amount for matching different size sheets and the offset amount of the sheet bundle after matching. In such a configuration, the control means 75 makes the left and right side matching members 46 stand by at a predetermined standby position (sheet width size + α position) based on the sheet size information provided by the image forming unit A or the like.

In this state, the sheet is carried onto the processing tray, and the matching operation is started at the timing when the sheet edge abuts on the sheet edge regulating member 41. In this matching operation, the left and right matching motors M6 and M7 are rotated by the same amount in opposite directions (approaching directions). Then, the sheets carried into the processing tray 24 are positioned with reference to the sheet center and stacked in a bundle. By repeating the loading operation and the matching operation of the sheets, the sheets are aligned and accumulated in a bundle on the processing tray. At this time, sheets of different sizes are positioned with reference to the center, for example.

Position sensors (not shown) such as a position sensor and an encode sensor are arranged on the left and right side matching members 46F and 46R and their matching motors M6 and M7, and the position of the side matching member 46 can be detected. The matching motors M6 and M7 are composed of stepping motors, the home position of the side matching member 46 is detected by a position sensor (not shown), and the motor is PWM controlled, so that the left and right side matching members have a relatively simple control configuration. 46F and 46R can be controlled.

[Sheet bundle unloading mechanism]
Next, the sheet bundle unloading mechanism (sheet bundle unloading means 60) will be described. The processing tray 24 is provided with a sheet bundle unloading mechanism for carrying out the sheet bundles bound by the first and second binding means (26, 27) to the loading tray 25 on the downstream side. In the processing tray 24, as shown in FIG. 4, the first seat rear end regulating member 41A is located in the seat center Sx, and the second and third seat rear end regulating members 41B and 41C are arranged on the left and right sides of the processing tray 24. Have been placed. Then, the sheet bundle locked to the regulation member 41 is bound by the binding means (26, 27) and then carried out to the loading tray 25 on the downstream side.

For this purpose, the processing tray 24 is provided with sheet bundle unloading means along the paper mounting surface 24a. The sheet bundle unloading means shown in FIG. 4 is composed of a first transport member 60A and a second transport member 60B, the first section L1 on the processing tray is the first transport member 60A, and the second section L2 is the second transport. Relay transport is performed by member 60B. By taking over and transporting the sheets with the first and second transport members 60A and 60B in this way, the mechanism of each transport member can be made to have a different structure. The member that conveys the sheet bundle from substantially the same start point as the sheet rear end regulating means 40 is composed of a member with less fluctuation (long support member), and the member that drops the sheet bundle onto the loading tray 25 at the end of the transfer is a member. , Must be small (to run on a loop trail).

Then, the first transport member 60A moves to the downstream side at a speed V1 from the seat rear end regulation position by one-way rotation of the drive motor M4, and pushes and transfers the rear end of the seat bundle at the locking surface 61a. A predetermined time delay from the first transport member 60A, the second transport member 60B projects from the standby position on the back side of the processing tray onto the paper mounting surface, follows the first transport member 60A, and travels in the same direction at a speed V2. Moving. At this time, if the speed is set so that V1 <V2, the sheet bundle on the processing tray 24 is taken over from the first transport member 60A to the second transport member 60B.

Then, when the second transport member 60B hits the sheet bundle traveling at the speed V1 at a high speed at the takeover point, the paper surface pressing member 64 presses the upper surface of the sheet bundle with the paper surface pressing surface 64a to press the carrier member (belt) 65a. While holding the rear end of the sheet bundle so as to nip with (65b), the sheet is carried out toward the loading tray 25.

[Binding processing method (binding position)]
As described above, the sheets sent to the carry-in inlet 21 of the first paper ejection path 22 are aligned and accumulated on the processing tray, and are positioned at the positions and postures preset by the sheet edge regulating member 40 and the side matching member 46 ( Consistency). Therefore, this sheet bundle is bound and carried out to the loading tray 25 on the downstream side. The binding processing method in this case will be described.

[Multi-binding]
As shown in FIG. 4, in the multi-binding process, the edge of the sheet bundle (hereinafter referred to as “matching sheet bundle”) positioned on the processing tray 24 by the sheet edge regulating member 41 and the side matching member 46 (the one shown in the drawing is The trailing edge) is bound. In FIG. 4, binding positions Ma1 and Ma2 for binding two locations at intervals are set. The stapler unit (26), which will be described later, moves from the home position to the binding position Ma1 and then to the binding position Ma2, and performs binding processing. The multi-binding position Ma is not limited to two locations, and may be bound to three or more locations. FIG. 5A shows a multi-bound state.

[Corner binding]
The corner binding process is performed at two locations on the left and right, the right corner binding position Cp1 for binding the right corner of the matching sheet bundle accumulated in the processing tray 24 and the left corner binding position Cp2 for binding the left corner of the matching sheet bundle. The binding position is set. In this case, the staples are tilted by a predetermined angle (about 30 degrees to about 60 degrees) for binding. (The stapler unit (26) described later is mounted on the apparatus frame so that the entire unit is tilted by a predetermined angle at this position.) FIGS. 5 (b) and 5 (c) show corner-bound states.

The device specifications shown in FIG. 4 show a case where either the left or right side of the sheet bundle is selected for binding processing, and a case where the staple needle is tilted by a predetermined angle for binding processing. Not limited to this, a configuration in which corner binding is performed on either the left or right side, or a configuration in which the staple needle is bound parallel to the edge of the sheet without tilting can be adopted.

[Stapler unit]
The stapler unit (26) is already widely known as a stapler binding device. An example thereof will be described with reference to FIG. The stapler unit (26) is configured separately from the sheet binding processing device B (post-processing device). A box-shaped unit frame 26a, a drive cam 26d oscillatingly supported by the frame, and a drive motor M8 that rotates the drive cam 26d are mounted on the frame.

The staple head 26b and the anvil member 26c are arranged to face each other at the binding position on the drive cam 26d, and the staple head moves up and down from the upper standby position to the lower staple position (anvil member) by an urging spring (not shown) on the drive cam. Move. A needle cartridge 39 is detachably attached to the unit frame.

A straight blank needle is housed in the needle cartridge 39, and the needle is supplied to the head 26b by a needle feed mechanism. The head portion 26b contains a former member that bends a straight needle into a U shape and a screwdriver that press-fits the bent needle into a bundle of seats. With such a configuration, the drive motor M8 rotates the drive cam 26d and stores it in the urging spring. Then, when the rotation angle reaches a predetermined angle, the head portion 26b vigorously descends toward the anvil member 26c. In this operation, the staple needle is bent into a U shape and then inserted into the sheet bundle with a screwdriver. The tip is bent by the anvil member 26c and stapled.

[Loading tray]
Here, the configuration of the loading tray will be described with reference to FIG. 7. The loading tray 25 is arranged on the downstream side of the processing tray 24, and loads and stores a bundle of sheets accumulated in the processing tray. It is provided with a tray elevating means for controlling the loading tray 25 so that the tray 25 is sequentially lowered according to the load capacity. The loading surface (top sheet height) of this tray is controlled to a height position that is substantially flush with the paper loading surface of the processing tray. Further, the loaded sheet is inclined at an angle at which the rear end edge in the paper ejection direction abuts on the tray matching surface (standing surface) 20f due to its own weight.

[Tray lifting means]
As shown in FIG. 7, in this tray elevating means, for example, an elevating rail 54 is fixed to the device frame 20a up and down in the loading direction, and the tray base 25x can be moved up and down on the elevating rail by a slide roller 55 or the like. Is fitted to. At the same time, a rack 25r is integrally formed on the tray base 25x in the elevating direction, and a drive pinion 56 axially supported by the apparatus frame 20a is meshed with the rack 25r. A lift motor M10 is connected to the drive pinion 56 via a worm gear 57 and a worm wheel 58.

Therefore, by reversing the elevating motor M10 in the forward and reverse directions, the rack 25r connected to the drive pinion 56 moves up and down above and below the device frame. With this configuration, the tray base 25x can be moved up and down in a cantilevered state. As the tray elevating means, a pulley suspension belt mechanism or the like may be used in addition to the rack and pinion mechanism.

A loading tray 25 is integrally attached to the tray base 25x, and the sheets are loaded and stored on the loading surface 25a. Further, the device frame 20a is formed with tray matching surfaces 20f that support the trailing edge of the sheet in the vertical direction in the loading direction of the sheet, and the one shown in FIG. 7 forms the tray matching surface with the outer casing. Further, the loading tray 25 integrally attached to the tray base 25x is formed so as to be inclined in the angular direction as shown in the drawing, and the angle is set (for example, 20) so that the rear end abuts on the tray matching surface 20f due to the weight of the sheet. Degrees to 60 degrees).

[Sheet holding mechanism]
The loading tray 25 is provided with a paper pressing mechanism 53 that presses the stacked top sheets. The paper pressing mechanism 53 of FIG. 7 includes an elastic pressing member 53a that presses the uppermost sheet, a shaft support member 53b that rotatably supports the elastic pressing member on the device frame 20a, and the shaft support member in a predetermined angular direction. It is composed of a drive motor that rotates and its transmission mechanism.

The shaft support member 53b and the drive motor that rotates the shaft support member in a predetermined angle direction are driven and connected by using the drive motor of the sheet bundle unloading mechanism as a drive source, and when the seat bundle is carried in (carried out) to the loading tray 25. The elastic pressing member 53a retracts to the outside of the tray, and after the rear end of the sheet bundle is stored on the top sheet of the loading tray, it rotates counterclockwise from the standby position and engages on the top sheet. Press it together.

Further, the elastic pressing member 53a retracts from the paper surface of the uppermost sheet on the loading tray 25 to a retracted position by the initial rotation operation of the drive motor that carries out the sheet bundle on the processing tray toward the loading tray 25.

[Tray height detection means]
A level sensor LS is arranged on the loading tray 25 as a tray height detecting means for detecting the paper surface height of the top sheet, and the above-mentioned hoisting motor is rotated by the detection signal of the level sensor LS to rotate the tray paper mounting surface 25a. Move up. Various configurations are known as this type of level sensor, but the one shown in FIG. 7 irradiates the detection light above the tray from the tray matching surface 20f of the apparatus frame 20a, detects the reflected light, and has a height thereof. Detects whether or not the sheet exists at the position.

[Loaded sheet amount sensor]
Similar to the level sensor LS, the loading tray 25 is provided with a loading sheet amount sensor that detects that the sheet has been removed from the tray. Although the detailed structure of these is not described in detail, for example, a sensor lever that rotates integrally with the above-mentioned paper holding elastic pressing member 53a is provided, and the sheet exists on the loading surface by detecting the sensor lever with the sensor element. Whether or not it can be detected.

When the height position of the sensor lever is different (changed) before and after the sheet bundle is carried out, the control means 75, which will be described later, for example stops the paper ejection operation or raises the tray to a predetermined position. It should be noted that such an operation is an abnormal operation and is a problem that occurs when the user carelessly takes out the sheet from the loading tray while the device is in operation. Further, the lower limit position is set so that the loading tray 25 does not descend abnormally. For example, a limit sensor or the like can be provided to detect the lower limit position of the loading tray 25.

[Means for recognizing the number of loaded sheets]
The post-processing unit B of the present embodiment includes an optional sheet number recognizing means for recognizing the number of sheets loaded on the loading tray 25. Specifically, the number of sheets loaded on the loading tray 25 can be recognized by counting the sheets that have passed through the paper ejection port 23 by the control CPU 75 described later. The number of loaded sheets is configured to be reset when the above-mentioned load sheet amount sensor detects that a sheet has been removed from the loading tray 25.

[Loading sheet size recognition means]
Further, the post-processing unit B includes a sheet size recognizing means for recognizing the size of the sheet loaded on the loading tray 25. For example, which of the sizes of each of the plurality of cassettes of the paper feeding unit configured in the image forming unit A described later is discharged is transmitted from the image forming unit A to the post-processing unit B as a signal. As a result, the size of the sheet discharged onto the loading tray 25 and loaded can be recognized.

[Recording means]
Further, the post-processing unit B includes a recording means capable of recording the number of sheets loaded and the sheet size recognized by the loaded sheet size recognizing means in association with predetermined information. For example, by recording predetermined information in the recording means when a paper jam is detected by the sheet sensor Se2 arranged on the first transfer path 22, when the subsequent sheet transfer (job) is executed. It can be utilized. For this recording means, for example, a predetermined storage area of the RAM 77 can be used.

[Image formation system]
As shown in FIG. 1, the image forming unit A is composed of a paper feeding unit 1, an image forming unit 2, a paper ejection unit 3, and a signal processing unit (not shown), and is built in the device housing 4. In the present embodiment, the paper feed unit 1 is composed of a cassette 5 for storing sheets, and is composed of a plurality of cassettes 5a, 5b, and 5c so that sheets of different sizes can be stored. Each of the cassettes 5a to 5c has a built-in paper feed roller 6 for feeding out the sheets and a separation means (separation claw, separation roller, etc .; not shown) for separating the sheets one by one.

Further, the paper feeding unit 1 is provided with a paper feeding path 7, and the sheets are fed from each cassette 5 to the image forming unit 2. A resist roller pair 8 is provided at the path end of the paper feed path 7, and the sheets sent from each cassette 5 are aligned at the tip and wait until the sheet is fed according to the image formation timing of the image forming unit 2.

As described above, the paper feed unit 1 is composed of a plurality of cassettes according to the device specifications, and is configured to feed the sheet of the size selected by the control unit to the image forming unit 2 on the downstream side. Each of the cassettes 5 is detachably attached to the device housing 4 so that the seat can be replenished.

As the image forming unit 2, various image forming mechanisms for forming an image on the sheet can be adopted. The one shown in the figure shows an electrostatic image forming mechanism. As shown in FIG. 1, a plurality of drums 9a to 9d composed of photoconductors (photoconductors) are arranged in the device housing 4 according to the color components. A light emitter (laser head or the like) 10 and a developer 11 are arranged on the drums 9a, 9b, 9c, and 9d. Then, a latent image (electrostatic image) is formed on each of the drums 9a to 9d by the light emitter 10, and the toner ink is adhered by the developer 11. The ink image adhering to each drum is transferred to the transfer belt 12 for each color component and image-synthesized.

The transferred image formed on the belt is transferred to the sheet sent from the paper feeding unit 1 by the charger 13, fixed by the fixing device (heating roller) 14, and then sent to the paper ejection unit 3. The paper ejection unit 3 is composed of a paper ejection port 16 for carrying out the sheet to the paper ejection space 15 formed in the device housing 4, and a paper ejection path 17 for guiding the sheet from the image forming unit 2 to the paper ejection port. There is. A duplex path 18, which will be described later, is continuously provided in the paper ejection unit 3, and the sheet on which the image is formed on the surface is inverted and fed to the image forming unit 2 again.

The duplex path 18 flips the sheet image-formed on the surface side by the image-forming unit 2 and retransmits it to the image-forming unit 2. Then, after the image forming unit 2 forms an image on the back surface side, the image is carried out from the paper ejection port 16. Therefore, the duplex path 18 is composed of a switchback path that reverses the transport direction and returns the sheet sent from the image forming unit 2 to the apparatus, and a U-turn path 18a that reverses the sheet returned to the apparatus. ing. In the illustrated device, this switchback path is formed in the first paper ejection path 22 of the post-processing unit B, which will be described later.

[Image reading unit]
The image reading unit C is composed of a platen 19a and a reading carriage 19b that reciprocates along the platen. The platen 19a is made of transparent glass and is composed of a still image reading surface for scanning a still image by moving the reading carriage 19b and a traveling image reading surface for reading a document image traveling at a predetermined speed.

The reading carriage 19b includes a light source lamp, a reflecting mirror that changes the reflected light from the document, and a photoelectric conversion element (not shown). The photoelectric conversion element is composed of line sensors arranged in the document width direction (main scanning direction) on the platen, and the scanning carriage 19b reciprocates in the sub-scanning direction orthogonal to the line sensor to read the document image in line order. It has become. Further, an automatic document feeding unit D for traveling the document at a predetermined speed is mounted above the traveling image reading surface of the platen 19a. The document automatic feeding unit D includes, for example, a feeder mechanism that feeds the document sheets set on the paper feed tray one by one to the platen 19a, reads the image, and then stores the document sheet in the output tray.

[Explanation of control configuration]
The control configuration of the image forming system described above is shown as a block diagram in FIG. The image forming system shown in FIG. 8 includes a control unit 70 (hereinafter referred to as a main body control unit) of the image forming unit A and a control unit 75 (hereinafter referred to as “binding processing control unit”) of a post-processing unit B (sheet binding processing device; the same applies hereinafter). ") Is provided. The main body control unit 70 includes a print control unit 71, a paper feed control unit 72, and an input unit 73 (control panel).

Further, the "image formation mode" and the "post-processing mode" can be set by using the input unit 73 (control panel). In the image formation mode setting, mode settings such as color / monochrome printing and double-sided / single-sided printing and image formation conditions such as sheet size, sheet quality, number of printouts, and enlargement / reduction printing can be set. Further, in the post-processing mode setting, for example, "printout mode", "staple binding processing mode", "eco-binding processing mode", "jog sorting mode", and the like can be set and selected. In addition to automatic binding, a manual binding mode can be provided. In this manual binding mode, for example, the sheet bundle binding processing operation is executed offline independently of the main body control unit 70 of the image forming unit A.

Further, the main body control unit 70 transfers data such as a post-processing mode, the number of sheets, the number of copies information, and the paper thickness information of the sheet for forming an image to the binding processing control unit 75. At the same time, the main body control unit 70 transfers the job end signal to the binding processing control unit 75 each time the image formation is completed.

Explaining the post-processing mode described above, the “printout mode” accommodates the sheets discharged from the paper ejection port 23 in the loading tray 25 via the processing tray 24 without binding processing. In this case, the sheets are stacked on the processing tray 24 and accumulated, and the accumulated sheet bundle is carried out to the loading tray 25 by the jog end signal from the main body control unit 70.

In the above-mentioned "staple binding processing mode (second paper ejection mode)", the sheets from the paper ejection port 23 are collected on the processing tray and aligned, and the sheet bundle is bound and then stored in the loading tray 25. Is. In this case, the sheet to be image-formed is, in principle, designated by the operator as a sheet having the same paper thickness and the same size. As the staple binding processing mode, one of the above-mentioned "multi-binding", "right corner binding", and "left corner binding" can be selected.

In the "jog sorting mode", control is performed to classify the sheets image-formed by the image forming unit A into a group that is offset and accumulated on the processing tray and a group that is accumulated without offsetting. Alternately offset sheet bundles and non-offset sheet bundles are stacked on the loading tray 25.

In the device of the present embodiment, an offset area is provided on the front side of the device, and as shown in FIG. 4, for example, as shown in FIG. 4, the same as the group in which the sheets carried out from the paper ejection port 23 at the center reference Sx are collected in that posture on the processing tray. The sheets carried out according to the center reference Sx are offset to the front side Fr of the device by a predetermined amount and divided into groups to be accumulated.

The reason why the offset area is arranged on the Fr on the front side of the device in this way is to secure a work area for manual binding processing, replacement processing of the needle cartridge, and the like on the front side of the device. The size of this offset area may be set to a size (about several centimeters) that makes it easy to divide the sheet bundle.

[Binding processing control unit]
The binding processing control unit 75 (control CPU 75) operates the post-processing unit B according to the post-processing mode set by the image formation control unit 70. The illustrated binding processing control unit 75 is composed of a control CPU (hereinafter, simply referred to as a control means). The ROM 76 and the RAM 77 are connected to the control CPU 75, and the paper ejection operation is controlled by using the control program stored in the ROM 76 and the control data stored in the RAM 77. Therefore, the control CPU 75 is connected to the drive circuits of all the drive motors including the elevating motors for operating the elevating means for elevating and lowering the loading tray 25, and controls each motor to start, stop, and forward / reverse.

"Paper jam detection function"
When the post-processing unit B determines that the sheet guided to the first paper ejection path 22 cannot be conveyed to the paper ejection port 23, the post-processing unit B detects an abnormality as a paper jam event. As an example of detecting a paper jam, the sheet sensor Se2 arranged on the first transport path 22 near the upstream side of the paper ejection port 23 is turned OFF → ON → in a normal state as the sheet passes during sheet transport. It changes to OFF. On the other hand, when the seat cannot pass in front of the sensor, the seat sensor Se2 or the seat sensor Se2 remains ON and does not change. The control CPU 75 detects a paper jam event when it recognizes that the sheet sensor Se2 remains ON for a predetermined time.

The cause of this paper jam will be described along with the sheet transport order in the post-processing unit B. The sheet discharged from the image forming unit A is temporarily stored in the processing tray 24 as shown in FIG. 9A because the post-processing unit B performs a predetermined post-processing. At this time, as shown in FIG. 9A, the sheets are stored in the loading tray 25 or in a state of straddling between the top sheet already discharged to the loading tray 25 and the processing tray 24. Further, the sheet stored in the processing tray 24 following the previously ejected sheet is conveyed while the tip of the sheet is in contact with the previously ejected sheet as shown in FIG. 9B. Therefore, the position of the top sheet loaded at the top position on the loading tray 25 is controlled by the level sensor so as to have a constant height, and the position where the tip of the sheet to be conveyed contacts is kept constant for processing. The storage performance of the sheet in the tray 24 is ensured.

It is known that the sheet discharged from the image forming unit A to the post-processing unit B causes warpage (curl) of the sheet in the image forming process. The degree of curl depends on various factors such as the material, thickness, and water content of the sheet, and it often depends on the brand of the sheet. In recent years, it has become necessary for this type of device to handle a wide variety of sheets. It's getting better.

[Paper jam in curl sheet]
FIG. 10 shows a state when the curl sheet is loaded on the loading tray 25. The height detected by the height detecting means (level sensor LS) that detects the position of the paper surface on the loading tray 25 and the actual height of the paper surface may differ greatly depending on the curl sheet being loaded. For example, as shown in FIG. 10A, when a predetermined number or more of curl sheets are loaded on the loading tray 25, the tip of the sheet newly stored in the processing tray 24 that is subsequently conveyed is normal. Contact the previously ejected sheet at different high positions. Such a transporting state causes a factor that the sheet cannot be transported normally any more. When the sheet is transported normally as shown in FIG. 10A, the sheet sensor Se2 on the sheet transport path 22 detects the occurrence of a paper jam.

Paper jams due to the loading of curl sheets as described above tend to occur when a predetermined number or more of sheets having curl characteristics are loaded on the loading tray 25. Although it depends on the degree of warpage of the curl sheet, in the transport state as shown in FIG. 10A, the detection result by the paper surface height detecting means of the loading tray 25 and the actual loading height of the curl sheet do not match. .. The discrepancy between this detection result and the actual height increases as the number of loaded sheets increases, and tends to cause a paper jam at a predetermined number of loaded sheets on the loading tray. For example, a phenomenon such as "in a job of copying 100 copies on A4 copy paper of a certain brand, a paper jam occurs when about 80 sheets are ejected with high probability" occurs.

Therefore, in the present embodiment, when a paper jam (paper jam due to detection of the stagnant sheet on the sheet sensor Se2) occurs due to a defective discharge in the transport path, the paper jam occurs during sheet transport after clearing the paper jam. By moving the loading tray 25 to a lower position than when it occurred, the recurrence of the paper jam is prevented. As a result, even when a large number of curl sheets are loaded on the loading tray 25, the height of the loading tray 25 can be moved to a position lowered by a predetermined amount by the elevating means as shown in FIG. 10B. For example, the tip of the sheet that is subsequently discharged comes into contact with the sheet on the loading tray 25 at a relatively low position, and the occurrence of a paper jam in the subsequent processing can be suppressed.

Further, it is conceivable to record the number of loaded sheets recognized by the loading sheet number recognizing means of the loading tray 25 when a paper jam occurs in the recording means as the above-mentioned limit number of curl sheet loading. In that case, the number of loaded sheets of the loaded sheet number recognizing means is monitored, and the limit number of sheets recorded in the recording means is sequentially compared. As a result, the height of the loading tray 25 is increased before the number of loaded trays 25 reaches the limit after the subsequent sheet transfer (JOB), for example, one, several, or several tens of sheets. It is possible to control the lowering to a position lower than the position where the paper jam has occurred. As described above, the occurrence of poor recognition of the height of the loading tray 25 due to the curl sheet tends to occur in a predetermined number of sheets. Therefore, that is, the number of loaded sheets (limit number of sheets) of the loading tray 25 when a paper jam occurs is recorded in the recording means, and the loading tray 25 is proactively set before the limit number of sheets in the previous predetermined job. It is controlled to lower to a position lower than the generated position. By such control, it is possible to realize a paper jam recurrence prevention control that prevents the tendency of paper jams to occur.

Further, the size of the sheet recognized by the loading sheet size recognizing means when a paper jam occurs may be recorded in the recording means together with the number of loaded sheets of the loading tray 25 at the time of occurrence. As a result, when a paper jam is recorded on a sheet of a certain size a predetermined number of times due to a defective discharge in a predetermined transport path, the number of loaded sheets different for each sheet size is set as the limit number of sheets to prevent the recurrence of the above-mentioned paper jam. Control can be performed.

Further, not only the detection of the paper jam by the sheet sensor Se2 described above, but also the condition of continuous occurrence is recorded for the abnormality that tends to occur recognized by various recognition means, and the recorded condition is used. Based on this, the lowering control of the loading tray 25 may be performed so as to prevent the occurrence of an abnormality in advance. As a result, information other than the size, for example, information depending on the curl such as the above-mentioned sheet brand is recorded in the recording means, and the number of loaded sheets different for each sheet brand is set as the limit number to prevent the above-mentioned abnormality from occurring in advance. The lowering control of the loading tray 25 can be performed so as to do so.

In the above, the curl sheet has been illustrated as an example to explain the lowering control of the loading tray 25 when a paper jam occurs in the sheet or in order to prevent it. However, the same control can be performed even when dealing with a sheet that has been folded. Further, when a paper jam occurs on the sheet, or whether or not to control the lowering of the loading tray 25 to prevent it is determined according to the processing mode and the switching of the paper feeding device in the image forming unit A. can do.

A ... image forming unit, B ... post-processing unit, C ... image reading unit.

Claims (3)

Sheet transporting means for transporting sheets discharged from the image forming apparatus, and
A loading tray for loading sheets transported by the sheet transport means, and
A tray height detecting means for detecting the height of the loading tray or the uppermost sheet loaded on the loading tray, and
A tray raising / lowering means for raising / lowering the loading tray based on the detection result of the tray height detecting means,
A paper jam detecting means for detecting the occurrence of a paper jam in which a sheet is not conveyed from the sheet transporting means to the loading tray, and
When a paper jam is detected by the paper jam detecting means, it is lower than the position where the paper jam is detected by the paper jam detecting means after the paper jam is cleared and before the sheet is conveyed from the sheet transporting means to the loading tray. A sheet loading device including a control means for controlling the tray elevating means so as to move the loading tray to a position. A sheet number recognition means for recognizing the number of sheets loaded on the loading tray, and
A recording means for recording the number of sheets recognized by the sheet number recognizing means when a paper jam is detected by the paper jam detecting means in a predetermined job is provided.
In a job different from the predetermined job, the control means causes the paper jam in the predetermined job before the number of sheets recognized by the sheet number recognizing means becomes the number of sheets recorded in the recording means. The sheet loading device according to claim 1, wherein the tray elevating means is controlled so as to move the loading tray to a position lower than a position where a paper jam is detected by the detecting means. It is provided with a size recognition means for recognizing the size of the sheet loaded on the loading tray.
The recording means further records the size of the sheet recognized by the size recognizing means when the paper jam detecting means detects a paper jam in the predetermined job.
The control means recognizes when a paper jam of the same size as the sheet transported by the sheet transporting means is recorded in the recording means in a job different from the predetermined job. From the position where the paper jam is detected by the paper jam detecting means for the sheet of the size recognized by the size recognizing means in the predetermined job before the number of sheets becomes the number of sheets recorded in the recording means. The sheet loading device according to claim 2, wherein the tray elevating means is controlled so as to move the loading tray to a lower position.

Images