JP2007031112A - Sheet treating device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet treating device capable of enhancing the efficiency by shortening the time required to perform post-treatment work through shortening of the time till the start of carrying in the following sheet even if the size in the feeding direction of the sheet foregoing in the mixed loaded mode is larger than the following sheet. <P>SOLUTION: The sheet treating device to treat the fed sheet is equipped with a first transport path A as a path for conducting post-treatment for carrying in the sheet toward the position where the post-treatment is conducted, a second transport path B branched from the position as the first transport path A retracting the sheet temporarily by moving it in reversal in the direction opposite the carry-in direction, and transporting members 6 capable of transporting pinchedly the sheet which are installed in front and in the rear about the sheet carry-in direction with the boundary existing in the branching position of the second transport path from the first transport path A, wherein the transporting members 6 carry in the following sheet to the first transport path A in the process of switching back the foregoing sheet toward the second transport path B after the foregoing sheet is carried in to the first transport path A. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet processing apparatus and an image forming apparatus, and more particularly to a mechanism that superimposes recording sheets such as recording sheets discharged from the image forming apparatus and conveys them to a post-processing unit.

In an image forming apparatus such as a copying machine, a printer, a facsimile machine or a printing machine, an image output can be obtained by transferring a visible image such as a toner image carried on a latent image carrier onto a recording sheet. ing.
Separately from the case where the recording sheets are sequentially discharged from the image forming apparatus onto the discharge tray, post-processing such as binding holes for the discharged recording sheets or binding processing for bookbinding is performed. May be executed.
An apparatus for post-processing, a so-called post-processing apparatus, is provided so as to be integrated or connectable to a discharge portion of the image forming apparatus, and is equipped with an apparatus for performing a post-processing step.
By the way, when the recording sheet to be subjected to the post-processing step is discharged without performing the post-processing, the recording sheet is discharged to a discharge tray attached to the post-processing device, but the discharge state to the post-processing device is set. In this case, while the preceding group of recording sheets is being post-processed, the subsequent recording sheets are kept in a bundle (standby pre-stack), Collecting the subsequent recording sheet group so that the subsequent recording sheet group can be consolidated within the post-processing time for the preceding recording sheet group by drawing out after the post-processing operation is performed. The time may be shortened (for example, Patent Document 1).

  As a configuration for holding the subsequent recording sheet group together and waiting, the recording sheet branched from the recording sheet loading path toward the post-processing apparatus and introduced into the loading path is reversed and the subsequent recording is performed. There is a configuration including a reversal conveyance path that temporarily stops and waits until a sheet is introduced (for example, Patent Document 2).

  In Patent Document 1, a reverse conveyance path that branches in a substantially Y shape from a merging portion provided in a part of the recording sheet carry-in path to the post-processing apparatus, and a recording sheet carry-in path and a reverse conveyance path are provided. A recording member that is capable of sandwiching and conveying the recording sheet, and the recording sheet previously introduced into the recording sheet carry-in path is temporarily switched back to the reverse conveyance path and waited for the subsequent recording sheet. By feeding the preceding recording sheet that has been waiting on the reverse conveyance path in accordance with the timing at which the recording sheet is introduced into the recording sheet carry-in path, the preceding and subsequent recording sheets are conveyed toward the post-processing device in a state of being overlapped with each other. ing.

  On the other hand, in addition to the post-processing apparatus main body such as a stapler, the post-processing apparatus is provided with a processing tray for mounting the introduced recording sheet bundle, and the introduced recording sheet bundle is loaded with the stacked recording sheets. Configuration in which the work by the main body of the post-processing apparatus is executed by hitting the rear end in the introduction direction with a hitting roller capable of contacting the uppermost one of the bundle and abutting and aligning with an end fence provided on the processing tray (For example, Patent Document 3).

JP 11-199128 A (paragraph "0003" column) JP 2003-2503 A (paragraph “0006” column) JP 2004-1998 A (paragraph “0045” column)

  As a configuration in which the recording sheet bundle is pre-stacked during the post-processing operation of the preceding recording sheet bundle, when a configuration capable of switching back to the reverse conveyance path is used, the preceding sheet material is carried into the reverse conveyance path. In the meantime, the succeeding sheet material cannot be carried out in order to avoid interference occurring with the preceding sheet material. For this reason, the time required for prestacking becomes long, and the efficiency of post-processing work cannot be achieved at present.

  In particular, the sheet material to be pre-stacked is not only the case where the size in the width direction, which is a direction perpendicular to the feeding direction of the sheet material, is the same, but also in the case where the length in the feeding direction is different. When the size of the preceding sheet material is larger than that of the subsequent sheet material, the standby time is longer and the work time required for the entire post-processing is longer than when the smaller sheet material is targeted. I can't deny it.

  In view of the problems in the conventional sheet processing apparatus described above, the object of the present invention is to start loading of the subsequent sheet material even when the preceding sheet material is larger in the feeding direction than the subsequent sheet material in the mixed loading mode. It is an object of the present invention to provide a sheet processing apparatus and an image forming apparatus having a configuration capable of reducing the time required for post-processing work and improving the efficiency.

  According to the first aspect of the present invention, in the conveyed sheet processing apparatus, as the path for the post-processing, a first transport path for carrying a sheet material toward a position where post-processing is performed, and the first A branch position between a second conveyance path that is branched from the conveyance path and temporarily retracts by reversing the sheet material in a direction opposite to the loading direction, and the second conveyance path in the first conveyance path. And a conveying member that is disposed on the front side and the rear side of the sheet in the carry-in direction of the sheet and capable of sandwiching and conveying the sheet material, the conveying member preceding the first conveying path. After the sheet is carried in, the subsequent sheet material is carried in toward the first conveyance path in the process of switching back the preceding sheet material toward the second conveyance path.

  According to a second aspect of the present invention, in the sheet processing apparatus according to the first aspect, the conveying member is a process in which a rear end of the preceding sheet material is retracted from the first conveying path to the second conveying path. While the subsequent sheet material is carried into the first conveying path, the preceding sheet material is in the process of being retracted to the second conveying path while the subsequent sheet material is carried into the first conveying path. The preceding sheet material is carried into the first conveying path together with the succeeding sheet material at a timing coincident with the rear end of the sheet material.

  According to a third aspect of the present invention, in the sheet processing apparatus according to the first or second aspect, the preceding sheet material and the subsequent sheet material are reversely conveyed toward the second conveying path. And the time when the subsequent sheet material is carried into the conveyance path is set to overlap.

  According to a fourth aspect of the present invention, in the sheet processing apparatus according to the first or second aspect of the present invention, the first of the conveying members is based on a branch position between the first conveying path and the second conveying path. The conveyance member positioned on the front side in the movement direction of the sheet material in the conveyance path can set the nipping conveyance position and the non-nipping conveyance position of the sheet material, and the subsequent sheet material is carried into the first conveyance path. It is characterized by being set to the non-nipping conveyance state when being performed.

  According to a fifth aspect of the present invention, in the sheet processing apparatus according to one of the first to fourth aspects, the rear end detection is arranged in the first conveying path and can detect passage of the rear end of the sheet material. Means, and the rear end detecting means and an operating portion capable of inputting the size of the sheet material are connected to the input side, and the output side of the conveying member capable of setting the position between the holding state and the non-holding state A control unit to which a drive unit is connected, and the control unit includes a distance between a rear end of a subsequent sheet material carried into the first conveyance path by the rear end detection unit and the branch position, and the first position. The conveying member in the non-clamping position is switched to the clamping position at the timing when the distance between the rear end of the preceding sheet material retracted in the conveyance path 2 and the branch position coincides, and both sheet materials are moved in the same direction. It is characterized by being fed to.

  According to a sixth aspect of the present invention, in the sheet processing apparatus according to the fifth aspect, when the preceding sheet material has a larger size in the feed direction than the subsequent sheet material, the control unit changes the position of the conveying member. The preceding sheet material is set to a state in which the preceding sheet material is reversed and conveyed toward the second conveyance path, and the subsequent sheet material is carried into the first conveyance path while being reversed and conveyed toward the second conveyance path. In this case, the conveying member is set in a non-clamping position of the sheet material, and a state in which the subsequent sheet material and the conveying member do not interfere with each other is set.

  According to a seventh aspect of the present invention, in the sheet processing apparatus according to the fifth or sixth aspect, when the preceding and subsequent sheet materials have the same size in the feeding direction, the control unit moves the preceding sheet material into the reverse conveyance path. When the subsequent sheet material is carried into the first conveyance path during the reverse conveyance process, the conveyance member is set to the non-nip conveyance state, and at the timing when the rear ends of both the sheet materials match. After the conveyance member is switched to the nipping conveyance position and both sheet materials are carried into the first conveyance path, both sheet materials are moved to the second conveyance path in a state where the conveyance member is switched to the non-nipping conveyance position. In the process in which the sheet material whose size in the feeding direction is newly smaller than the preceding and subsequent sheet materials is carried into the first conveying path in the process of reversing and conveying the sheet, the conveying member is switched to the non-nip conveying state, and the process In the second The conveying member is set in the nipping and conveying state at a timing when the trailing edge of the preceding and succeeding sheet material reversed and conveyed on the feeding path coincides with the trailing edge of the new sheet material conveyed to the first conveying path. The three sheets are fed in the same direction.

  The invention according to claim 8 is characterized in that the sheet processing apparatus according to one of claims 1 to 7 is used in an image forming apparatus.

  According to the first and fifth aspects of the present invention, after the sheet material preceding the first conveyance path is carried in by the conveyance member, the preceding sheet material is switched back toward the second conveyance path. In the process, the subsequent sheet material is conveyed toward the first conveyance path. In the process of conveying the preceding sheet material, it becomes possible to convey the subsequent sheet material until the subsequent sheet material starts to be conveyed. The waiting time can be shortened.

According to the second aspect of the present invention, while the trailing end of the preceding sheet material is retracted from the first conveyance path to the second conveyance path, the subsequent sheet material is carried toward the first conveyance path. In the process in which the succeeding sheet material is carried into the first transport path, the succeeding sheet material is moved to the succeeding sheet material at the timing when the trailing edge coincides with the trailing edge of the preceding sheet material in the process of retreating to the second transport path. Since the sheet material is carried into the first conveyance path together with the sheet material, the preceding sheet material that has been retreated to the second conveyance path in the process in which the subsequent sheet material is carried into the first conveyance path is provided. Since the sheet is re-drawn, the re-feeding time for the preceding sheet material retracted on the second conveyance path can be advanced.
In addition, since the switchback direction and the carry-in direction are opposite to each other, it is possible to advance the rear end timing of the sheet materials that move in these directions, and to reduce the amount of movement of the sheet material that moves in the switchback direction. This makes it possible to add power to the drive system and reduce energy consumption.

  According to the third aspect of the present invention, the time when the preceding sheet material is reversely conveyed to the second conveyance path and the time when the subsequent sheet material is carried into the first conveyance path are overlapped. Therefore, it can be obtained as a time shortening portion when the conveyance of the sheet material having a continuous overlapping period is intended.

  According to the fourth aspect of the present invention, since the conveying member located on the front side in the moving direction of the sheet material carried in the vicinity of the merging position is switched to the non-nipping conveyance state when the subsequent sheet material is carried in, the subsequent sheet The conveyance of the subsequent sheet material can be disclosed in the process of conveying the preceding sheet material without hindering the material carry-in, so that it is possible to reduce the time for continuously conveying a plurality of sheet materials.

  According to the sixth aspect of the present invention, in the mixed loading mode in which the sheet materials having different sizes are conveyed, when the preceding sheet material has a smaller size in the feeding direction than the succeeding sheet material, the preceding sheet material is second. By moving the conveying member to the non-clamping position during the reverse conveyance to the conveyance path, it is possible to prevent the movement of the subsequent sheet material from being hindered. By doing so, it is possible to shorten the waiting time until the start of the conveyance of the subsequent sheet material.

  According to the seventh aspect of the present invention, in the mixed loading mode of the sixth aspect, when the preceding and subsequent sheet materials have the same size in the feeding direction, the preceding sheet material is reversely conveyed to the second conveying path. In this way, the subsequent sheet material is carried into the first conveyance, so that the waiting time until the subsequent sheet material starts conveyance can be shortened. When a new sheet material with a small size is carried into the first conveyance path, the conveyance member can be switched to the non-nip conveyance state so that the new sheet material is not obstructed. Since the three sheet materials are fed in the same direction at the timing when the trailing edges of the three sheet materials are matched in the process in which the subsequent sheet material is reversed and conveyed, the preceding and subsequent sheet materials are It becomes possible to re-feed out until the sheet is completely retracted on the second conveying path, and thus, the amount that can be re-drawn before completion of the retracting to the second conveying path is required for the three-sheet sheet overlap conveyance. It can be obtained as a time reduction.

  According to the eighth aspect of the present invention, when a plurality of sheet materials are continuously conveyed, a part of the conveyance timing can be overlapped, so the time until the conveyance of the subsequent sheet material is shortened. As a result, the time required for the entire post-processing can be shortened and workability can be improved.

  The best mode for carrying out the present invention will be described below with reference to embodiments shown in the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a sheet post-processing apparatus used as a sheet processing apparatus in the present embodiment. The sheet post-processing apparatus according to the present embodiment is a recording sheet in an image forming processing apparatus such as a copying machine or a printer. Although it is used by being connected to the discharge unit, it can also be used by being incorporated in the image forming apparatus.

In FIG. 1, a sheet post-processing apparatus 1 is connected by being attached to a side portion of an image forming apparatus 2, and a sheet as one of recording sheets discharged from the image forming apparatus 2 is a sheet post-processing apparatus 1. Led to. The configuration of the sheet post-processing apparatus 1 will be described together with the operation as follows.
The sheet S enters the sheet post-processing apparatus 1 from the receiving port 2a, is detected by the inlet sensor SN1, and is transported by the transport rollers 4 and 5 serving as transport members, and the branch claw 2e is rotated counterclockwise in the figure. By being rotated, it is guided to the lower transport path 2b.
The sheet S guided to the lower conveyance path 2b rotates the switching claw 9 in the counterclockwise direction in the figure by its own moving force, passes through the first conveyance path A secured thereby, and a conveyance roller as a conveyance member. 6, 7 and 8 are conveyed to the processing tray 13.
After the paper S passes, the switching claw 9 returns to the illustrated position by the tension of a spring (not shown).
When the sheet S transported through the first transport path A is introduced into the processing tray 13, the sheet S falls by its own weight in the direction of arrow C, and is struck down by the tapping roller 14, and is transported in the transport direction by the rear end fence 11. The trailing edge is aligned. When the trailing edge of the sheet S is detected in advance by the sensor SN2, the edge in the width direction is aligned by the alignment fence 10 after a time during which the sheet conveyance direction can be aligned. This operation is repeated to form the aligned sheet bundle 1z in the processing tray 13.

The aligned sheet bundle 1z is stapled by the staple 12, and then moved in the direction of arrow D by the discharge claw 15 provided in parallel with the sheet conveyance direction at the center of the processing tray 13.
The discharge claw 15 is operated by a drive system (not shown) via a discharge belt 17 that is wound between the rollers 16a and 16b.

  The sheet bundle 1z moves in the direction of arrow E while being pushed by the discharge claw 15 at the rear end, and is stacked on the sheet discharge tray 3 by the sheet discharge roller 18.

The first transport path A is connected to a second transport path B that joins the first transport path A.
The second conveyance path B is partly branched to form a reverse path that is detoured in an inverted U shape from the branch position, and the switching claw 9 described above is disposed in the vicinity of the branch position. Yes.

In the first transport path A, the transport rollers 5 to 8 described above are arranged along the moving direction of the paper S. In the present embodiment, the arrangement pitch of the conveying rollers 5 to 8 is set to a pitch that allows the sheet to be nipped and conveyed within a small-sized feed direction length (longitudinal length). As a result, the paper can be transported by any of the adjacent transport rollers.
Among the transport rollers, the transport rollers 6 and 7 located on the front side in the moving direction of the sheet S with respect to the branch position with respect to the second transport path B are rollers capable of rotating forward and backward, and among these rollers, The transport rollers 6 positioned in the vicinity of the switching claw 9 can select a nipping and transporting position in which the sheets S can be nipped and transported in contact with each other and a non-nipping and transporting position in which the sheets cannot be nipped and transported. It is configured to be able to contact and separate. The conveying member is not limited to a roller, and a belt or the like can be used.

  The transport roller 6 located in the vicinity of the switching claw 9 can rotate forward and backward to set the loading state of the paper S into the first transport path A and from the first transport path A to the second. It is used as a forward / reverse moving transport member (hereinafter, the transport roller 6 is referred to as a forward / reverse moving transport member) that can select a carry-out position in which the paper S is switched back (reverse transported) toward the transport path B. It has become.

On the other hand, the position setting of the forward / reverse moving conveyance member 6 is performed by the control unit 200 shown in FIG.
In FIG. 2, the control unit 200 uses a control unit that executes an image forming process sequence in the image forming apparatus 500. As a configuration related to the present embodiment, an operation panel 201, an entrance sensor SN1, and a first one are provided on the input side. A trailing edge detection sensor SN2 that can detect that the trailing edge of the sheet S has passed through a predetermined position in the conveyance path A is connected, and on the output side, the drive unit for the staple 12 and the conveyance member 6 for forward / reverse movement are driven. The parts (for convenience, the names of the members are shown in FIG. 2) are connected to each other.

  In the control unit 200, in the mixed loading mode in which the length in the feeding direction of the sheet material carried into the first conveyance path A is a target, when the preceding paper has a larger size in the feeding direction than the following paper, In the process in which the sheet is switched back from the first conveyance path A to the second conveyance path B, control is performed to carry the subsequent sheet into the first conveyance path A, thereby starting the conveyance of the subsequent sheet. When doing so, it is not necessary to wait until the preceding paper has completely completed the switchback.

  That is, FIG. 3 is a diagram for explaining the movement state of the sheet material in this case. In FIG. 3, in order to carry the preceding large-size sheet S1 into the first conveyance path A, it is for forward and reverse movement. The forward / reverse transport roller 6 which is a transport member is set to the nipping and transporting position. In this state, when the preceding large-size sheet S1 is carried and the leading end reaches the conveying roller 7 and is nipped, the forward / reverse conveying roller 6 is switched to the non-nipping state (see FIG. 3A).

The preceding large-size sheet S1 carried into the first conveyance path A is switched back toward the second conveyance path B by the reverse rotation of the conveyance roller 7, and the rear end thereof is retracted to the second conveyance path B. (See FIG. 3B).
On the other hand, in the process of retracting the trailing edge of the preceding large-size sheet S1 into the second conveyance path B, the subsequent small-size sheet S2 starts to be carried into the first conveyance path A (see FIG. 3C). ). At this time, the carry-in start timing of the succeeding small-size sheet S2 is from the time when the rear end of the preceding large-size sheet S1 starts to be introduced into the second transport path B until the leading edge reaches a position where it does not come off the transport roller 7. The period is between.

  In the process in which the preceding large-size sheet S1 is switched back into the second conveyance path B, the trailing ends of both of them coincide at the stage where the succeeding small-size sheet S2 is carried into the first conveyance path A. The preceding large-size sheet S1 that has been retreated in the second conveyance path B according to the timing is re-delivered toward the first conveyance path A. Here, the preceding large-size sheet S1 and the succeeding small-size sheet S2 are fed in the same direction, that is, in the first transport path A with the trailing ends thereof matched (FIG. 3) D. )reference).

FIG. 4 illustrates the paper conveyance start state shown in FIG. 3 in terms of time. In FIG. 4, the forward and reverse indications indicate the rotation directions of the forward / reverse moving transport member (forward / reverse transport roller) 6 and the transport roller 7.
In FIG. 4, when the preceding (first sheet) sheet S1 is carried into the first conveyance path A, it is switched back toward the second conveyance path B. However, in the conventional case, the switchback is completed. Then, when the succeeding paper S2 is carried into the first transport path A, the timing is set (T0).

  On the other hand, in this embodiment, the timing (T1) when the subsequent paper S2 starts to be carried into the first transport path A during the period when the preceding paper S1 is switched back to the second transport path B. ) Is set. As a result, in this embodiment and the conventional case, a time difference of (T0−T1) is obtained in the waiting time until the subsequent paper S2 starts to be carried in, and thereby the subsequent paper S2 is started to be carried in. Can be shortened.

FIG. 5 is a flowchart for explaining this procedure. In FIG. 5, it is determined whether or not the leading end of the preceding (first sheet) large-size sheet S1 has reached the nipping position of the transport roller 7 (ST1). It is determined whether the trailing edge of the sheet S1 has passed through the switching claw 9 (ST2).
When it is determined that the trailing edge of the preceding (first sheet) large-size sheet S1 has passed through the switching claw 9, the preceding (first sheet) large-size sheet S1 is switched to the second transport path B. A back-up operation is performed (ST3). At this time, the forward / reverse moving transport member (forward / reverse transport roller) 6 is switched to the non-nipping transport position (ST4), and the subsequent (second sheet) small-size sheet S2 is transferred to the first transport path A. (ST5).

  In the process in which the preceding (first sheet) large-size sheet S1 and the succeeding (second sheet) small-size sheet S2 move through the respective conveyance paths, it is determined whether the trailing ends of both sheets match ( ST6). In this determination, based on the sheet size and the sheet conveyance speed, for example, it is determined whether or not the rear end conveyed to the merging position of both conveyance paths coincides, and the conveyance for forward / reverse movement is performed at the timing when the rear ends coincide. The forward / reverse transport roller 6 as a member is switched to the nipping state and both sheets S1, S2 are stacked and fed to the same direction, that is, the first transport path A (ST7, 8).

  According to the present embodiment, it is possible to shorten the time until the start of the conveyance of the subsequent sheet due to the relationship in which a part of the conveyance timing to each conveyance path is overlapped.

  In particular, since the direction in which the preceding paper S1 is switched back is opposite to the direction in which the subsequent paper S2 is carried in, the timing at which the trailing edges of both papers coincide can be obtained early. As a result, the amount of movement of the preceding paper S1 to be switched back can be reduced.

On the other hand, the mixed loading mode includes a case where not only two sheets but also three sheets are double fed. This case will be described below.
FIG. 6 shows that the preceding and succeeding sheets S1 and S2 have the same size in the feeding direction, and a sheet newly introduced separately from these sheets is smaller than the preceding and succeeding sheets S1 and S2 in the feeding direction. It is a figure which shows the procedure aimed at the case.

In FIG. 6, the states shown in (1) and (B) are the same as the states shown in (A) and (B) in FIG. Then, in the process in which the preceding large-size sheet S1 is switched back from the first conveyance path A toward the second conveyance path B, the subsequent large-size sheet S2 is carried into the first conveyance path A (FIG. 6). (Refer to (C) and (D)), the forward / reverse transport roller 6 which is a forward / reverse movement transport member that has been set to the non-nip transport state at the timing when the leading edges of the preceding and succeeding sheets S1, S2 coincide. Is switched to the nipping and transporting state, and both the sheets S1 and S2 are fed into the first transport path A in a state in which the leading ends coincide with each other, in other words, in a state in which the trailing ends coincide with each other. When the state where the rear end faces the forward / reverse transport roller 6 through the position 9 is obtained, the forward / reverse transport roller 6 is switched to the non-nip transport state, and a new small size sheet S3 is first The carrying-in is started to the conveyance path A (see FIG. 6F). As a result, when a new small-size sheet S3 is carried into the first conveyance path A, it is carried into the first conveyance path A without being blocked by the forward and reverse conveyance rollers 6.
In the process in which the succeeding small-size sheet S3 is carried into the first transport path A, the forward / reverse transport roller 5 is switched to the nipping and transporting position at a timing coincident with the rear ends of the preceding and succeeding large-size sheets S1 and S2. Then, the three sheets are fed in the same direction in the first conveyance path A with the sheets stacked (see FIG. 6G).

FIG. 7 is a flowchart for explaining the procedure in this case. In FIG. 7, the procedures from reference numerals ST1 to ST6 are the same as those shown in FIG.
The first transport path A is carried in a state in which the rear ends of the preceding and succeeding sheets S1 and S2 match (ST9), and it is determined whether or not the leading ends have reached a position nipped by the transport rollers 7 ( Next, it is determined whether or not the rear end has passed the position of the switching claw 9 (ST11). Although not shown in FIG. 7, when both the preceding and succeeding sheets are carried into the first transport path A, the forward / reverse transport roller 6 is set to the nipping transport position. .

When it is determined that the trailing ends of the preceding and succeeding sheets S1, S2 have passed the position of the switching claw 9, both the sheets S1, S2 are collectively switched back toward the second transport path B. (ST12) A new small-size sheet S3 is newly carried into the first transport path A (ST13).
The timing at which the rear end of the new small-size paper S3 carried into the first transport path A matches the rear ends of the two sheets in the process in which the preceding and subsequent papers S1 and S2 are switched back. Once determined (ST14), the three sheets S1 to S3 are fed together into the first transport path A (ST15).

1 is a schematic diagram illustrating a configuration of an image forming apparatus including a sheet processing apparatus corresponding to a sheet processing apparatus according to an embodiment of the present invention. It is a block diagram for demonstrating the control part structure used for the sheet processing apparatus by a present Example. It is a figure for demonstrating the conveyance state which made object the paper of a different size carried in to the sheet processing apparatus by a present Example. FIG. 3 is a timing chart for explaining a principle related to conveyance control executed by a control unit shown in FIG. 2. FIG. It is a flowchart for demonstrating the procedure shown in FIG. It is a figure for demonstrating another conveyance state for P paper of a different size carried in to the sheet processing apparatus by a present Example. It is a flowchart for demonstrating the process sequence shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sheet processing apparatus 2 Image forming apparatus 6 Forward / reverse moving conveying member 7 Conveying roller 9 Switching claw 12 Staple 13 Processing tray 200 Control unit A First conveying path B Second conveying path

Claims (8)

In the sheet processing apparatus being conveyed,
As a path for the post-processing, a first transport path for carrying the sheet material toward a position where the post-processing is performed,
A second conveyance path that is branched from the first conveyance path, and temporarily retracts by reversing the sheet material in the direction opposite to the loading direction;
A conveyance member that is arranged on the front side and the rear side in the sheet loading direction with respect to the branch position with the second conveyance path in the first conveyance path, and capable of sandwiching and conveying the sheet material,
The conveyance member is configured to switch the subsequent sheet material in the process of switching back the preceding sheet material toward the second conveyance path after the preceding sheet material is carried into the first conveyance path. A sheet processing apparatus which carries in toward the first conveyance path. The sheet processing apparatus according to claim 1,
The conveying member carries in the subsequent sheet material toward the first conveying path while the rear end of the preceding sheet material retreats from the first conveying path to the second conveying path, while the subsequent In the process in which the sheet material is carried into the first conveyance path, the preceding sheet material is moved to the subsequent sheet at the timing when the trailing edge matches the trailing edge of the preceding sheet material in the process of being retracted to the second conveyance path. A sheet processing apparatus, wherein the sheet processing apparatus is carried into the first conveyance path together with a material. In the sheet processing apparatus according to claim 1 or 2,
The preceding sheet material and the succeeding sheet material are in excess of the timing when the preceding sheet material is reversed and conveyed toward the second conveying path and the timing when the succeeding sheet material is carried into the conveying path. A sheet processing apparatus in which a wrapping relationship is set. In the sheet processing apparatus according to claim 1 or 2,
Among the conveying members, the conveying member located on the front side in the moving direction of the sheet material in the first conveying path with respect to the branch position between the first conveying path and the second conveying path is the sheet material. The nipping conveyance state and the non-nipping conveyance position can be set, and when the subsequent sheet material is carried into the first conveyance path, the sheet is set to the non-nipping conveyance state. Processing equipment. In the sheet processing apparatus according to any one of claims 1 to 4,
A rear end detection means arranged in the first conveyance path and capable of detecting passage of the rear end of the sheet material;
The rear end detection means and the operation unit capable of inputting the size of the sheet material are connected to the input side, and the drive unit of the conveying member capable of setting the holding position and the non-holding position on the output side. A connected control unit,
The control unit includes a rear end of a subsequent sheet material that is carried into the first conveyance path by the rear end detection unit, a distance to the branch position, and a preceding sheet material that is retreated in the second conveyance path. A sheet processing apparatus, wherein the conveying member in the non-clamping position is switched to the clamping position at a timing at which the distance between the rear end and the branch position coincides to feed both sheet materials in the same direction. The sheet processing apparatus according to claim 5, wherein
The control unit is configured such that when the preceding sheet material is larger in the feeding direction than the succeeding sheet material, the preceding sheet material is reversed and conveyed toward the second conveying path. And when the subsequent sheet material is carried into the first conveyance path while being reversed and conveyed toward the second conveyance path, the conveyance member is set to a non-nipping state of the sheet material. Then, the sheet processing apparatus is set so that the subsequent sheet material and the conveying member do not interfere with each other. The sheet processing apparatus according to claim 5 or 6,
When the preceding and subsequent sheet materials have the same size in the feeding direction, the control unit reversely conveys the preceding sheet material toward the reverse conveying path, and moves the subsequent sheet material to the first conveying path in the reverse conveying process. When carrying in, the conveying member is set to a non-nipping conveying position, and when the rear ends of both sheet materials match, the conveying member is switched to the nipping conveying position, and both sheet materials are moved to the first conveying path. In the process of reversing and conveying both sheet materials toward the second conveyance path in a state where the conveying member is switched to the non-nip conveyance state after being carried in, the size in the feeding direction is newly larger than the preceding and subsequent sheet materials. In the process in which a sheet material having a small size is carried into the first conveyance path, the conveyance member is switched to the non-nipping conveyance position, and the rear ends of the preceding and subsequent sheet materials that are reversed and conveyed to the second conveyance path in that process And the first carrying A sheet processing apparatus for feeding three sheets of sheets in the same direction by setting the conveying member in a nipping and conveying position at a timing when the trailing edge of a new sheet material carried into the path matches. .   An image forming apparatus using the sheet processing apparatus according to claim 1.

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