JP4497713B2 - Sheet processing apparatus and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet processing apparatus that performs processing such as discharge, stacking, and alignment of sheets, and is applied to, for example, an image forming apparatus.
[0002]
[Prior art]
Conventionally, a ring-shaped rotating body (hereinafter referred to as “knurling”) that applies a conveying force to a trailing end stopper disposed on the trailing end of a processing tray for sheets on the processing tray to be stacked and aligned after image formation. Sheet processing using a sheet pressing member (hereinafter referred to as a “rear end dropping member”) that drops the rear end of the discharged sheet in order to improve the penetration into the knurled belt. The device is widely disclosed.
[0003]
Although the detailed description is omitted here, as shown in FIGS. 15 and 16, the sheet processing apparatus includes a plurality of knurled belts 1182 arranged in the axial direction of the pair of discharge rollers 1007, and discharge rollers. The trailing edge of the sheet discharged from the pair 1007 is received by the stopper 1131 and stacked on the stacking tray (hereinafter referred to as “processing tray”) 1130 and the sheet conveyance path downstream of the pair of paper discharge rollers 1007 and jumps at the leading edge of the sheet. A trailing edge dropping member 1181 that biases the trailing edge of the discharged and discharged sheet and guides the trailing edge of the sheet to the stopper 1131.
[0004]
The trailing edge dropping member 1181 swings about a central axis 1181a between a lowered position (dashed line) when the sheet is not conveyed and an upper position (solid line) when the sheet is conveyed.
[0005]
The rear end dropping member 1181 at the upper position urges the upper surface of the sheet downward by its own gravity, and when the sheet passes through the discharge roller pair 1007, the behavior and time when the sheet is dropped are stabilized. Then, the rear end of the sheet is pushed down and moved to the lowered position.
[0006]
Thereafter, when the sheet is transported to the stopper 1131 by the weight of the sheet and the conveyance force of the paddle 1160, the trailing edge dropping member 1181 has an inclined guide surface so that the trailing edge of the sheet does not hit the knurled belt 1182. The rear end of the sheet is guided by 1181d.
[0007]
[Problems to be solved by the invention]
However, in the case of the prior art as described above, the following problems have occurred.
[0008]
When the weight of the trailing edge dropping member 1181 is increased and the guide surface is enlarged in order to shorten the falling time of the trailing edge of the sheet or to improve the guiding effect, the sheet is buckled and discharged by increasing the load on the leading edge of the sheet. 15 (see the sheet S1 in FIG. 15), or a predetermined discharge angle cannot be obtained and it faces downward and comes into contact with an already stacked sheet, and the already aligned sheet already aligned is shifted by the impact (see FIG. 16). (See sheet S2).
[0009]
Such a phenomenon becomes prominent because the waist of the sheet becomes weaker as the distance L between the pressing surface 1181c of the trailing edge dropping member 1181 and the paper discharge roller pair 1007 becomes longer.
[0010]
Further, when the diameter of the knurled belt 1182 is enlarged, the trailing edge dropping member 1181 is also enlarged, and the distance L is increased, so that the above problem is likely to occur.
[0011]
Further, when the sheet is conveyed and the leading end of the sheet comes into contact with the trailing edge dropping member 1181 in the lowered position within the sheet passing locus, the sheet jumps instantaneously, but the trailing edge dropping member 1181 then swings in the direction of jumping. 1150 is in contact with the swing fulcrum shaft 1151.
[0012]
Then, the trailing edge dropping member 1181 after abutting as described above due to the abutting reaction acts in the direction of pushing down the sheet downward. In this case as well, the same problem as described above occurs.
[0013]
Therefore, it has been desired to avoid discharge failure due to buckling of the front end of the sheet and alignment failure in which the discharge sheet is pushed out against the already stacked sheets on the processing tray.
[0014]
SUMMARY An advantage of some aspects of the invention is that it provides a sheet processing apparatus and an image forming apparatus that prevent sheet stacking failure.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, in the sheet processing apparatus of the present invention, a conveying unit that conveys a sheet, a stacking tray that sequentially receives and stacks the sheets conveyed by the conveying unit , and disposed above the stacking tray And a sheet pressing device that urges the sheet conveyed by the conveying unit to the stacking tray side, wherein the sheet pressing member is placed in a sheet passing locus and a sheet passing locus by the conveying unit . A rotation drive mechanism that rotates upward is provided, and the rotation drive mechanism moves the sheet pressing member above the sheet passing locus before the front end of the sheet conveyance direction enters the pressing region of the sheet pressing member. is rotated to, before the conveying direction trailing end of the sheet comes out of the pressing area of the sheet pressing member, that rotates the sheet pressing member to the sheet passing through the trajectory And butterflies.
[0016]
It is preferable that the rotation of the sheet pressing member from above the sheet passing locus into the sheet passing locus is due to the weight of the sheet pressing member.
[0017]
The rotation driving mechanism abuts against a part of the sheet pressing member located in the sheet passing locus, and rotates the sheet pressing member above the sheet passing locus by displacing the contact surface. Is preferred.
[0019]
Running and sheet detecting means, the switching operation of the rotation driving mechanism by the detection signal by said sheet detection means for detecting the conveying direction leading edge and the trailing edge of the sheets arranged in the conveying direction upstream of the press area of the sheet pressing member And a control unit configured to switch the operation of the rotation drive mechanism after a predetermined time has elapsed since the sheet detection unit detected the leading edge in the sheet conveyance direction. Is retracted above the sheet passing locus , and after a predetermined time has elapsed since the sheet detecting means has detected the trailing end of the sheet conveyance direction , the operation of the rotation drive mechanism is switched and the sheet pressing member is moved to the sheet. It is preferable to perform control for positioning in the passage locus.
[0020]
In the image forming apparatus of the present invention,
The above sheet processing apparatus;
Image forming means for forming an image on a sheet disposed upstream of the sheet processing apparatus;
It is provided with.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Exemplary embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to those unless otherwise specified. Absent.
[0022]
A sheet processing apparatus according to an embodiment and an image forming apparatus to which the sheet processing apparatus is applied will be described with reference to FIGS.
[0023]
(Overview of overall sheet processing apparatus)
In FIG. 1, a sheet processing apparatus (hereinafter referred to as “finisher”) 1 is installed in an image forming apparatus main body 300, and a discharge sheet on which an image is formed by the image forming apparatus main body 300 is conveyed.
[0024]
In FIG. 1, the sheet on which the image is formed by the image forming apparatus main body 300 is discharged from the discharge roller pair 905. The sheet is conveyed from the entrance roller pair 2 of the finisher 1 into the finisher 1. A conveying roller pair 3 is provided downstream of the inlet roller pair 2, and a sheet detection sensor 31 is provided between the inlet roller pair 2 and the conveying roller pair 3.
[0025]
A punch unit 50 is provided downstream of the conveying roller pair 3, and a large conveying roller 5 and pressing rollers 12, 13, and 14 that press and convey the surrounding sheets are disposed downstream of the punch unit 50.
[0026]
The switching flapper 11 switches between the non-sort path 21 and the sort path 22. A switching flapper 10 at the entrance of the sort path 22 switches between the sort path 22 and a buffer path 23 for temporarily storing sheets.
[0027]
A transport roller 6 is provided in the sort path 22. On an intermediate tray (hereinafter referred to as “processing tray”) 130 as a stacking tray disposed downstream of the sort path 22, temporary stacking, alignment, stapling, and the like of sheets can be performed.
[0028]
The discharge roller 7 at the exit of the sort path 22 discharges the sheet onto the processing tray 130. The upper bundle discharge roller 180b is supported by the swing guide 150, and when the swing guide 150 moves to the closed position, the upper bundle discharge roller 180b cooperates with the lower bundle discharge roller 180a disposed on the processing tray 130 to remove the sheet on the processing tray 130. The bundle is conveyed and discharged onto the stack tray 200.
[0029]
That is, the swing guide 150 is tilted, and a pair of rollers is formed by the lower bundle discharge roller 180a and the upper bundle discharge roller 180b, and the sheets on the processing tray 130 are conveyed in a bundle.
[0030]
(Detailed explanation of the transport section and rear end dropping member)
Next, based on FIGS. 2, 3, and 4, the periphery of the conveyance unit and the sheet pressing member (hereinafter referred to as “rear end dropping member”) will be described in detail.
[0031]
The sort path 22 near the discharge roller pair 7 of the transport unit is provided with a sensor 183 that detects a sheet moving on the sort path 22. This sensor 183 is connected to the control circuit 301 of the finisher 1.
[0032]
The control circuit 301 is connected to a control device 930 in the copying machine main body (see FIG. 1), and controls not only the operation of the sheet processing apparatus but also the linkage operation with the copying machine main body.
[0033]
A rear end dropping member 181 and a knurled belt 182 are disposed around the downstream end of the sort path 22 where the discharge roller pair 7 of the transport unit is disposed.
[0034]
As shown in FIG. 4, a plurality of trailing edge dropping members 181 and knurling belts 182 are arranged in the axial direction intersecting the sheet conveying direction. In this case, the trailing edge is sandwiched between the knurling belts 182 at both ends. A drop member 181 is attached.
[0035]
The rear end dropping member 181 is provided on the swinging center shaft 181d so as to be swingable in the vertical direction. Normally, when there is no sheet passing, the rear end dropping member 181 stands by at the position indicated by the solid line (lowering position) in FIG. Then, the one end of the rear dumping member 181, and (see FIG. 4) with the cam surface 181a is formed so as to engage the link 184, the cam surface 181a is pushed down by the operation of the link 184 (dashed state), As a result, the rear end dropping member 181 swings clockwise in FIG.
[0036]
Here, the link 184 and the cam surface 181a are not completely connected. When the link 184 is in the position of the solid line, the rear end dropping member 181 can freely swing between the position of the solid line and the broken line. It is supported by.
[0037]
Link 184 is supported rotation center as shown in FIG. 4, a portion is engaged with the aforementioned cam surfaces 181a, is connected to a solenoid SL1 as rotary drive mechanism, ON of the solenoid SL1 / By the OFF operation, as shown in FIG. 3, the rear end dropping member 181 is rotated to the position indicated by the solid line and the broken line.
[0038]
At the other end of the trailing edge dropping member 181, there are formed a sheet guide surface 181 b and a pressing surface 181 c that presses the trailing edge of the discharged and floating sheet downward. In a state where SL1 is ON (that is, a state where the sheet is retracted out of the sheet passing locus), the sheet does not contact the pressing surface 181c (see FIG. 6).
[0039]
In a state where the solenoid SL1 is turned off while the sheet is being discharged (that is, in a state where the solenoid SL1 is positioned in the sheet passing locus), the trailing edge dropping member 181 is not restrained by the link 184 but moves downward on the sheet upper surface by the pressing surface 181c. (See FIG. 7).
[0040]
The sheet guide surface 181b has the sheet rear end directed upward from the center (belly) of the knurled belt 182 when the sheet is discharged and moved to the rear end stopper 131 by its own weight and the conveyance force of the paddle 160. It is intended to guide you so that nothing happens.
[0041]
When the rear end of the sheet is discharged from the roller pair 7, the pressing surface 181c pushes the discharged rear end of the sheet downward from the center (belly) of the knurled belt 182 within a predetermined time. The predetermined time varies depending on the productivity of the apparatus, but is preferably before the return operation by the paddle 160 is started (see FIG. 8).
[0042]
Next, operation details of the solenoid SL1 will be described. As shown in FIG. 5, the solenoid SL1 is controlled based on the output of the paper detection sensor 183 in the sort path 22, and the solenoid SL1 is turned on after a predetermined time (t1) has elapsed since the leading edge of the sheet reaches the sensor 183. Further, the solenoid SL1 is controlled to be turned off after a predetermined time (t2) has elapsed since the rear end of the sheet has passed the sensor 183.
[0043]
Since t1 is set to a timing at which the leading edge of the sheet does not collide with the trailing edge dropping member 181 and t2 is set to be a timing before the trailing edge of the sheet passes through the nip of the roller pair 7, the above-described timing is set. As described above, it is obvious that the front end of the sheet can prevent the occurrence of trouble in sheet conveyance and can obtain the downward urging force with respect to the rear end of the sheet as usual.
[0044]
Here, the urging force by the pressing surface 181c of the trailing edge dropping member 181 with respect to the sheet is exemplified by the weight of the trailing edge dropping member 181 in this embodiment, but the present invention is not limited to this. For example, an urging means such as a spring (not shown) may be provided. In response to this urging force, the seat is pushed down from the center (belly) of the knurled belt 182 within a predetermined time and settled.
[0045]
Next, the sheet is pulled back to the rear end stopper 131 of the processing tray 130 by its own weight and the rotation of the paddle 160, but as shown in FIG. 8, the rear end of the sheet is guided by the guide surface 181b of the rear end dropping member 181; It can move without being caught by the knurled belt 182.
[0046]
(Sheet flow in each mode)
Next, the flow of the sheet P will be described with reference to FIGS.
[0047]
9 to 13, the description of the operation of the trailing edge dropping member 181 and the knurled belt 182 shown in FIG. 5 is omitted based on FIGS. 3 to 8.
[0048]
(Sheet flow in non-sort mode)
When the user designates the non-sort mode with the operation unit (not shown) of the image forming apparatus main body 300, as shown in FIG. 9, the entrance roller pair 2, the transport roller pair 3, and the transport large roller 5 rotate, The sheet P on which an image is formed by the image forming apparatus main body 300 is conveyed.
[0049]
The flapper 11 rotates to the position shown in the figure by the action of a solenoid (not shown), and conveys the sheet P to the non-sort path 21. When the sensor 33 detects the trailing edge of the sheet P, the roller 9 is driven to rotate at a speed suitable for stacking and discharges the sheet P to the sample tray 201.
[0050]
(Sheet flow in staple sort mode)
Next, an operation when the user designates the staple sort mode will be described.
[0051]
As shown in FIG. 10, the entrance roller pair 2, the transport roller pair 3, and the transport large roller 5 rotate to transport the sheet P on which an image is formed by the image forming apparatus main body 300.
[0052]
The flappers 10 and 11 are stopped at the position shown in FIG. The sheet P passes through the sort path 22 and is discharged onto the processing tray 130 by the discharge roller 7.
[0053]
The discharged sheet P starts to move to the trailing end stopper 131 (FIG. 2) under its own weight, and the paddle 160 that has been stopped at the home position is rotated counterclockwise by the driving of the motor M160. Assists the movement of the sheet P. When the trailing edge of the sheet P is reliably brought into contact with the trailing edge stopper 131 and stopped, the rotation of the paddle 160 is also stopped, and the front alignment mechanism and the stapler 101 align the discharged sheet P (see FIG. 11).
[0054]
When all the first sheets are discharged onto the processing tray 130 and aligned, the swing guide 150 is lowered as shown in FIG. 12, the upper bundle discharge roller 180b is placed on the sheet bundle, and the stapler 101 is The sheet bundle is stapled and the sheet bundle on the processing tray 130 is discharged onto the stack tray 200 as shown in FIGS.
[0055]
Next, an outline of the image forming apparatus main body 300 to which the finisher 1 is applied will be described with reference to FIG.
[0056]
A sheet deck 909 is disposed at the lower portion of the image forming apparatus main body 300, and the sheet P is supplied into the apparatus from here. Further, the sheet P is also supplied from the manual feed trays 910 and 911.
[0057]
Then, the sheet P conveyed into the apparatus is conveyed between the photosensitive drum 914 and the transfer apparatus 916 at the timing by the registration roller 901, and the image on the photosensitive drum 914 is transferred.
[0058]
Here, the photosensitive drum 914 is charged by the primary charger 919, and the document D placed on the document table 906 is irradiated by the light source 907 after being withstand power, and the image of the document D is exposed through the lens 908, thereby generating an electrostatic latent image. It is formed.
[0059]
Thereafter, the electrostatic latent image is developed with toner by the developing device 915, and the toner image is transferred onto the sheet.
[0060]
As described above, the image forming unit includes all apparatuses for forming a toner image on the sheet P.
[0061]
The residual toner remaining on the photosensitive drum 914 after the transfer is scraped off by a cleaning device.
[0062]
Then, the sheet P after the image transfer is conveyed by the conveying belt 920, the toner is melted and fixed by the fixing device 904, and is discharged from the discharge roller pair 905.
[0063]
【The invention's effect】
As described above, according to the present invention, it is possible to avoid a discharge failure due to the buckling of the leading end of the sheet, an alignment failure in which the discharge sheet is pushed out against the already stacked sheets on the stacking tray, and the like.
[Brief description of the drawings]
FIG. 1 is a front sectional view showing a sheet processing apparatus according to an embodiment.
FIG. 2 is an enlarged front sectional view showing a schematic configuration of a sheet processing apparatus according to an embodiment.
FIG. 3 is an enlarged front sectional view showing a schematic configuration of the sheet processing apparatus according to the embodiment.
FIG. 4 is a plan view showing an arrangement relationship between a trailing edge dropping member and a knurled belt according to the embodiment.
FIG. 5 is an operation explanatory diagram of the solenoid according to the embodiment.
FIG. 6 is an operation explanatory view of a trailing edge dropping member according to the embodiment.
FIG. 7 is an operation explanatory view of the trailing edge dropping member according to the embodiment.
FIG. 8 is an operation explanatory view of a trailing edge dropping member according to the embodiment.
FIG. 9 is an operation diagram of the sheet processing apparatus in a non-sort mode.
FIG. 10 is an operation diagram of the sheet processing apparatus in a staple sort mode.
FIG. 11 is an operation diagram of the sheet processing apparatus in a staple sort mode.
FIG. 12 is an operation diagram of the sheet processing apparatus in a staple sort mode.
FIG. 13 is an operation diagram of the sheet processing apparatus in a staple sort mode.
FIG. 14 is a front sectional view showing an image forming apparatus to which the sheet processing apparatus is applied.
FIG. 15 is a diagram for explaining a defect of a conventional rear end dropping member.
FIG. 16 is a diagram for explaining a problem of a conventional rear end dropping member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Finisher 2 Entrance roller pair 3 Conveyance roller pair 5 Conveyance roller pair 6 Conveyance roller 7 Discharge roller pair 9 Roller 10 Switching flapper 11 Switching flapper 12, 13, 14 Press roller 21 Non-sort path 22 Sort path 23 Buffer path 31 Sheet detection sensor 50 Punch unit 101 Stapler 130 Processing tray 131 Rear end stopper 150 Swing guide 160 Paddle 180a Lower bundle discharge roller 180b Upper bundle discharge roller 181 Rear end dropping member 181a Cam surface 181b Sheet guide surface 181c Press surface 181d Swing center shaft 182 Knurling belt 183 Paper detection sensor 184 Link 200 Stack tray 201 Sample tray 300 Image forming apparatus main body 301 Control circuit

Claims (6)

A transport unit for transporting the sheet;
A stacking tray for sequentially receiving and stacking sheets conveyed by the conveying unit ;
A sheet pressing member that is disposed above the stacking tray and biases the sheet transported by the transport unit toward the stacking tray;
In a sheet processing apparatus comprising:
A rotation driving mechanism for rotating the sheet pressing member and the upper sheet passing track within a sheet passing path by the transport section is provided,
The rotation driving mechanism rotates the sheet pressing member above the sheet passing locus before the leading end of the sheet in the conveying direction enters the pressing area of the sheet pressing member, and the trailing end of the sheet in the conveying direction is A sheet processing apparatus , wherein the sheet pressing member is rotated into a sheet passing locus before the sheet pressing member comes out of the pressing region of the sheet pressing member. The sheet processing apparatus according to claim 1, wherein the rotation of the sheet pressing member from above the sheet passing locus into the sheet passing locus is due to the weight of the sheet pressing member. The said rotation drive mechanism contact | abuts to a part of said sheet | seat press member located in a sheet | seat passage locus, and supports the said sheet | seat press member so that rotation is possible upwards. The sheet processing apparatus according to the description. The rotation driving mechanism abuts against a part of the sheet pressing member located in the sheet passing locus, and rotates the sheet pressing member above the sheet passing locus by displacing the contact surface. the sheet processing apparatus according to any one of claims 1 to 3, wherein. A sheet detecting means for detecting the conveying direction leading edge and the trailing edge of the sheets arranged in the conveying direction upstream of the press area of the sheet pressing member,
Control means for switching the operation of the rotation drive mechanism by a detection signal from the sheet detection means,
The control means switches the operation of the rotational drive mechanism after a predetermined time has elapsed after the sheet detecting means detects the leading edge of the sheet conveyance direction, and retracts the sheet pressing member above the sheet passing locus. And controlling the operation of the rotational drive mechanism to position the sheet pressing member in the sheet passing locus after a predetermined time has elapsed since the sheet detecting means detected the trailing edge of the sheet conveyance direction. The sheet processing apparatus according to claim 1, wherein the sheet processing apparatus performs the sheet processing. A sheet processing apparatus according to any one of claims 1 to 5;
An image forming apparatus comprising: an image forming unit configured to form an image on a sheet disposed upstream of the sheet processing apparatus.

Images