JP2001192148A - Sheet conveying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveying device capable of being offset in a simple structure without enlarging a driving means. SOLUTION: An offset roller 2 for conveying a sheet in a different direction from the sheet conveying direction of a pre-shift roller 1, and deflection is formed in at least one of places between the pre-shift roller 1 and the offset roller 2, and between the offset roller 2 and a post-shift roller 3 disposed downstream of it. A sheet is offset using this deflection without applying unnecessary force to the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus for conveying a printed sheet (sheet) in an image forming apparatus or the like, and more particularly to a technique for performing offset discharge on a printed sheet. It is.

[0002]

2. Description of the Related Art In a sheet conveying apparatus used in an image forming apparatus, a relative position of a sheet with respect to an image on a photosensitive drum is set to an appropriate positional relationship, or the sheet is offset on a sheet discharge tray. Various means for moving the sheet in a direction perpendicular to the sheet conveying direction are used for the purpose of discharging the sheet.

In Japanese Unexamined Utility Model Publication No. 62-200652 and Japanese Unexamined Patent Application Publication No. 7-304544 (first prior art), a sheet is conveyed when it is conveyed by a skew roller which conveys the sheet obliquely to the conveying direction. To correct the skew of the sheet,
There is disclosed a technique for correcting a skew of a sheet by bringing the sheet into contact with a side guide provided in parallel with the sheet conveying direction.

Further, Japanese Patent Application Laid-Open Nos. 1-294142 and 2-81858, and Japanese Utility Model Application Laid-Open No. Sho 62-203149.
In Japanese Patent Application Laid-Open Publication No. H10-15095 (second prior art), a conveying roller pair is moved integrally with a conveying roller shaft in a direction perpendicular to the sheet conveying direction, and the sheet is conveyed by the conveying roller. A technique for moving in a direction perpendicular to the transport direction is disclosed.

In Japanese Patent Application Laid-Open No. Hei 4-25158 (third prior art), a transport roller and a carriage supporting a transport roller shaft can be moved in a direction perpendicular to the sheet transport direction, and the transport roller transports the sheet. A technique is disclosed in which the sheet is moved in a direction perpendicular to the conveyance direction during the transfer.

In Japanese Patent Application Laid-Open No. 64-34836 (the fourth prior art), a transport roller is configured to be movable in an axial direction with respect to a transport roller shaft by a moving means, and a sheet is transported by the transport roller. While moving the sheet, a technique for moving the sheet in a direction perpendicular to the conveying direction is disclosed.

Further, Japanese Patent Application Laid-Open No. 6-16319 (5th
In the prior art), in order to prevent skipping of the drive gear of the conveyance roller shaft due to movement in the direction perpendicular to the sheet during rotation of the conveyance roller shaft and poor movement in the direction perpendicular to the sheet, which are problems in the second prior art. , And a problem with the third prior art,
In order to prevent image defects due to the occurrence of vibration caused by high-speed reciprocation of the carriage, the sheet is conveyed in a right angle direction by the guide means while the sheet is being conveyed by the conveyance means which does not pinch the sheet. There is disclosed a technology that enables offset discharge of a bird.

[0008]

However, the above-mentioned prior art has the following problems. That is, Japanese Utility Model Application Laid-Open No. 62-200652 and Japanese Patent Application Laid-Open No. 7-304544.
In the first prior art, such as Japanese Patent Application Publication No. H10-209, the sheet is brought into contact with the side guide to correct the skew of the sheet. Therefore, if the sheet is caught on the side guide during the shift, the sheet may break or jam. I do.

Further, JP-A-1-294142, JP-A-2-81858, and JP-A-62-203149.
In the second prior art, such as Japanese Patent Application Laid-Open No. H10-209, the transport roller pair is moved integrally with the transport roller shaft in a direction perpendicular to the transport direction, so that the torque to the transport roller increases, and the transport roller shaft becomes immovable. Or shortening the life of the transport roller or peripheral members due to gear breakage or the like.

Further, the method of moving the carriage supporting the rollers as disclosed in Japanese Patent Application Laid-Open No. H4-251058 is not suitable for high-speed reciprocating movement, and the inertia of the moving part is large, so that the vibration accompanying the movement is large. Occurs and the print quality is degraded.

In Japanese Patent Application Laid-Open No. 64-34836, the sheet is offset while the sheet is sandwiched by a plurality of conveying rollers. Therefore, the sheet is pulled in a direction perpendicular to the conveying direction, and the sheet may be damaged. May occur.

In Japanese Patent Application Laid-Open No. 6-16319,
In order to move the sheet in the right angle direction by the guide means, a castle for offsetting the sheet needs to be long in the conveyance path, and the apparatus becomes large.

In order to solve the above problems, it is an object of the present invention to provide a sheet conveying apparatus capable of realizing offset sheet discharging (conveying) with a simple structure without using a large-scale mechanism. And

[0014]

According to the present invention, at least one of a plurality of conveying means for conveying a sheet conveys a sheet in a direction different from that of another conveying means. Thus, the sheet is bent between the offset conveying means and the adjacent conveying means.

Thus, when the sheet is transferred between the two conveying means, the sheet tension can be relieved by utilizing the bending of the sheet, and the sheet can be offset without applying unnecessary force. It is possible to change the transport direction without giving a difference.

Further, even when one sheet is simultaneously conveyed by a plurality of conveying means arranged in the conveying direction, the conveying direction of the sheet can be changed.

[0017] As the sheet transporting apparatus having the above-described structure, the first to first embodiments
A third transport unit is provided, and the second transport unit is an offset transport unit. Then, after the sheet is bent between the second conveying means and the third conveying means and the conveying direction is changed by the second conveying means, the sheet is further moved in the same direction as the sheet conveying direction of the first conveying means. The sheet is delivered to the third transport unit that transports the sheet to the printer, thereby performing the offset discharge.

Further, if a bend is formed between the first conveying means and the second convey means and the bend is formed at two places, the sheet can be conveyed more smoothly, and the offset amount can be increased. Can be increased.

The deflection forming means for forming the deflection of the sheet includes, for example, a drive control by a controller for controlling the driving of each conveying means so that the downstream conveying means is slower than the conveying speed of the upstream conveying means. It can be realized by doing.

Here, the case where a bend is formed between the first transport means and the second transport means will be described.
The second transporting unit stops driving or sets the transporting speed to be lower than that of the first transporting unit, and transports the sheet by the first transporting unit. Even if the sheet arrives at the second conveying means, the conveyance of the sheet is regulated for a while, so that the sheet is pushed to the downstream side and the sheet is bent. After the flexure is formed, if the transport of the second transport means is started in accordance with the transport of the first transport means, the sheet is transported downstream by the second transport means while the flexure remains. You.

At this time, the arrival of the sheet to the second conveying means is determined by a non-contact sensor such as an optical sensor or a contact sensor such as a microswitch. It is sufficient that the conveyance is started after a predetermined time elapses after the detection and the activation of the timer from that time. Alternatively, after the sheet arrives at the second conveying means, it may be detected that the first conveying means has been operated by a predetermined amount, and the conveying may be started.

As another configuration, a stopper may be movably provided in the vicinity of the upstream side of the conveying means to restrict the advance of the sheet, and the sheet may be brought into contact with the stopper to form a bend. At this time, the second transport means may be driven or stopped, but if it is driven, transport can be performed as soon as the stopper is removed.

In the case where a bend is formed between the second conveying means and the third conveying means, the sheet whose direction has been changed by the second conveying means may become oblique as described later. 3 is transferred to the transfer means. Therefore, as described above, if the third conveying means is stopped or kept at a low speed for a while even if the sheet arrives, the sheet is bent while its leading end is in a state parallel to the third conveying means. Become. Thereafter, if the third conveying means is driven, the sheet is conveyed in an offset state.

The second conveying means can be switched between a holding state in which the sheet can be conveyed and a releasing state in which the sheet does not act on the sheet and does not participate in the sheet conveyance. When the holding state of the device is released, the mode is switched to a transport mode in which the sheet is directly delivered from the first transport device to the third transport device, and it is possible to select whether to execute the sheet offset or not. can do.

When the offset is not executed, the sheet is not damaged by changing the transport direction, so that high-speed transport is possible. As the release means, for example,
A configuration in which one of the pair of upper and lower rollers can be moved up and down by a motor, an air cylinder, or the like can be adopted.

In this case, the distance between the position where the first conveying means acts on the sheet and the position where the third conveying means acts on the sheet is determined by the distance of the conveyed sheet. It is set so as to be smaller than the minimum length in the transport direction.

As the conveying means used in the conveying apparatus described above, concretely, a method in which a sheet is sandwiched between a pair of upper and lower rollers and the rollers are rotated to convey the sheet,
It is possible to adopt a method of rotating and driving a pair of upper and lower belts wound around pulleys provided on the upstream side and the downstream side in the transport direction, a combination of belts and rollers, and the like.

Since the transport direction of the first transport means and the transport direction of the third transport means are the same direction, the rotation axes of these rollers or pulleys are orthogonal to the transport direction. Placed in

On the other hand, since the second conveying means needs to change the conveying direction of the sheet, specifically, a cylindrical roller is used, and its rotation axis is set to the rotation axis of the other conveying means. When the sheet is conveyed by a method in which the sheet is inclined and installed, or when the sheet is conveyed by a conveyance unit having at least one roller attached to the rotating shaft, the difference in the diameter of the left and right rollers is used to separate the other conveyance units. And a system in which the rotating shaft is inclined in the axial direction so that the left and right rollers are in contact with the sheet.

The shape of the rollers used in the first to third conveying means is preferably cylindrical in order to increase the contact area with the sheet. When using a roller having a difference in size between the left and right sides, the shape may be a truncated cone.

In the frustoconical roller described above, the peripheral speed is different in the axial direction, so that the sheet is conveyed while turning in the direction of the smaller diameter side. Therefore, it is also possible to combine such rollers. That is, the sheet conveyed from the first conveying means is rotated and conveyed in the left or right direction by the truncated conical roller, and further downstream in the left or right direction opposite to the conveying direction of the roller. A second truncated cone-shaped roller for rotatably conveying the sheet is provided, whereby the sheet posture can be returned to the same direction as the conveying direction of the first conveying means, and the sheets can be aligned.

At this time, the offset width can be adjusted by appropriately adjusting the size of the left and right rollers of the first truncated conical roller and the size of the right and left rollers of the second truncated conical roller. According to the above configuration,
Deformation is not required, and high-speed conveyance can be performed without reducing the sheet conveyance speed.

In the above arrangement, since the sheet is easily damaged when the sheet conveying direction is changed by the second conveying means, a releasing means for releasing the holding state of the first conveying means is provided. If the release means is operated after the sheet is delivered to the conveying means, the sheet is free from the restraint on the rear end side of the sheet, and the movement of the sheet is free, so that the damage to the sheet can be more reliably prevented. Becomes possible.

In another mode for changing the sheet conveying direction, the second conveying means offsets and conveys the sheet delivered from the first conveying means, and It is possible to adopt a configuration including a switching means for switching the sheet delivered from the first conveying means to the second posture for directly conveying the sheet in the same direction as the conveying direction of the first conveying means.

As the switching means, the second transport means is provided.
The sheet may be installed so as to convey the sheet in the same direction as the first and third conveying means, and may be movable at right angles or obliquely to the conveying direction. Specifically, a rail is laid in parallel with the rotation axis of the conveying means, and a belt driven by rotation of a pulley to be parallel to the rail is additionally provided. If the bearing of the rotating shaft is slidably mounted on the rail and the bearing is fixed to the belt, the rotating shaft can be moved together with the bearing in the axial direction. Further, a ball screw or an air cylinder may be used instead of the belt.

The operation of the transport device having such a configuration will be described. First, the first and second transport means are driven to transport a sheet, and the leading end of the sheet is sandwiched by the second transport means. At this time, the second transport unit is stopped.
As a result, the sheet is held by the second conveying means, and if only the first conveying means is driven in this state, the sheet is bent. After the sheet is bent, the switching means moves the second conveying means, for example, in a direction orthogonal to the conveying direction, and again drives the second conveying means to rotate. The force applied to the sheet is absorbed, and the sheet is conveyed to the third conveying unit in an offset state without causing damage. That is, since the rotation driving of the second transport unit and the movement by the moving unit are performed separately, there is no possibility that the load on the transport unit increases and the transport unit is damaged.

[0037]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

FIG. 1 shows an image forming apparatus (digital copying machine).
FIG. As shown in FIG. 1, the digital copying machine 30 is roughly divided into a scanner unit 31 as a document reading device, a laser recording unit 32, and a paper storing and conveying unit.

The scanner unit 31 includes a document table 35 made of transparent glass, and a double-sided automatic document feeder (RADF) for automatically feeding and conveying the document onto the document table 35.
36, and a document image reading unit for scanning and reading an image of a document placed on the document table 35, that is, a scanner unit 40.

The document image read by the scanner unit 31 is sent as image data to an image data input unit, which will be described later, and is subjected to predetermined image processing on the image data.
A paper tray 51, a first cassette 5
2, a second cassette 53, and a multi-bypass tray 54, and a duplex copying unit 55 for recording an image on the back side of a sheet on which an image is sent out from the sheet storage unit. ing.

Each of the cassettes in the sheet storage and transport section stores a bundle of sheets for each size. When an operator selects a cassette containing a desired size,
It is sent out one by one from the top of the bundle of paper in the cassette,
The paper is sequentially conveyed to the image forming unit of the laser recording unit 32 via the conveyance path 50.

The RADF 36 is a device for setting a plurality of documents at a time on a predetermined document tray and automatically feeding the set documents one by one onto the document table 35 of the scanner unit 40. is there. In addition, this RADF36
Is constituted by a transport path for a one-sided original, a transport path for a two-sided original, a transport path switching unit, and the like, so that the scanner unit 40 reads one or both sides of the original according to an operator's selection. . Since the RADF 36 is a known technique, further description will be omitted.

The scanner unit 40 includes a first scanning unit 40a having a lamp reflector assembly 41 for exposing the surface of a document and a first reflecting mirror 42a, and second and third scanning units.
Second scanning unit 4 including reflection mirrors 42b and 42c
0b, an optical lens body 43, and a photoelectric conversion element (CCD) 44 for converting a reflected light image from a document into an electric image signal.

The scanner section 31 sequentially places the documents to be read on the document table 35 by the related operation of the RADF 36 and the scanner unit 40, and moves the scanner unit 40 along the lower surface of the document table 35. While reading the original image. That is, the reflected light image from the original is reflected by the first, second and third reflection mirrors 4.
The light is reflected by 2a, 42b, and 42c, formed into an image on a CCD through an optical lens body, converted into an electric image signal, and output.

Image data obtained by reading a document image by the scanner unit 40 is sent to an image processing unit described later, and after being subjected to various processes, is stored in a memory. The image data is output to the laser writing unit 46 of the laser recording unit 32, and after being visualized as a visible image on the photosensitive drum 48 by an electrophotographic process, the image is transferred and formed on paper.

The laser recording unit 32 includes a laser writing unit 46 and an electrophotographic processing unit 47 for forming an image. The laser writing unit 46 includes a semiconductor laser that emits a laser beam corresponding to the image data from the memory, a polygon mirror that deflects the laser beam at a constant angular velocity, and a laser beam that is deflected at a constant angular velocity. It has an f-θ lens and the like that corrects the light to be deflected at a constant speed on the photosensitive drum 48.

The electrophotographic process section 47 includes a charging device, a developing device, a transfer device, a peeling device, a cleaning device, a static eliminator, and a fixing device 49 around a photosensitive drum 48 in a known manner.
Is arranged.

A sheet discharge conveyance path is provided downstream of the fixing device 49 in the sheet conveyance direction. A conveyance roller is provided in the sheet discharge conveyance path, and communicates with the post-processing device 34. A conveying path 56 leading to the duplex copying unit 55 branches off from the middle of the sheet discharge conveying path.

In the laser writing unit 46 and the electrophotographic processing unit 47, the laser beam is scanned by the laser writing unit 46 based on the image data read from the memory, so that the photosensitive drum 48
The electrostatic latent image is formed on the surface of the sheet, and the toner image visualized by the toner is electrostatically transferred onto the surface of the sheet conveyed from the sheet accommodating and conveying section, and then fixed.

The sheet on which the image has been formed in this way is sent from the fixing device 49 to the post-processing device 34 via the conveying roller 57 or the duplex copying unit 55 via the conveying path 56.
To be transported selectively. The sheet sent to the post-processing device 34 is supplied to the first discharge tray 341 or the second discharge tray 3.
42.

As described above, the image forming apparatus is provided with a sheet conveying device for conveying a sheet such as a document or a sheet along a conveying path. The present invention is an invention relating to these sheet conveying means. In the following embodiments, a case will be described in which offset discharge of a sheet is executed in the post-processing device 34 in FIG.

[First Embodiment] In the present embodiment, a conveying roller in which a plurality of pairs of upper and lower rollers are used as conveying means, and a sheet can be offset while the sheet is conveyed by the conveying rollers. Will be described.

FIG. 2 is a top view showing a sheet conveying device in which a plurality of conveying rollers are provided in a conveying path from the conveying roller 57 to the post-processing device 34 in FIG. Indicates the stage at which is transported. In the present embodiment, a case where the sheet S is conveyed horizontally in the conveyance path will be described.

This sheet conveying device includes a first conveying roller 1 for conveying a sheet in the direction A as a first conveying means, and the conveying roller 1 is disposed upstream as a pre-shift roller. . An offset roller 2 is disposed downstream of the first roller 1 as a second transport unit, and a post-shift roller 3 is disposed downstream thereof as a third transport unit.

Each of the rollers 57, 1 and 3 is composed of a pair of upper and lower cylindrical rollers having the same rotating shaft 57a, 1a and 3a.
, And each rotating shaft is arranged in parallel to each other so as to be orthogonal to the transport direction A. A gear is attached to each rotating shaft, and a driving force is transmitted from one motor via a clutch. Alternatively, a motor may be connected for each rotation axis and driven independently. In the upper and lower rotating shafts, the driving force is transmitted to one rotating shaft, and the other is driven.

On the other hand, the offset roller 2 differs from other roller shapes in that the left and right rollers 2b and 2c are each formed into a truncated cone shape, and the left roller has a longer circumference than the right roller. Therefore, the rotation shaft 2a of the offset roller 2
Is arranged in a direction orthogonal to the transport direction A,
It is installed in a state of being inclined not vertically but vertically, and can be in close contact with the sheet. A gear is also attached to this rotating shaft 2a, and like other rollers, it is driven to rotate by a motor, and the sheet is moved in the transport direction A. It is transported in an oblique direction.

In the pre-shift roller 1 and the offset roller 2, the driven rotation shaft is vertically movably supported so that the upper and lower rollers are separated from each other, and the rollers are mutually moved by releasing means such as a motor or a solenoid. The contact is separated. Here, when the upper and lower rollers are in contact with each other, the sheet is held so that the sheet can be conveyed.
The release state is set so as not to act on the seat.

Each of the rollers 1 and 2 is driven and controlled by a control device in the image forming apparatus, and is based on a detection signal from a sheet detector, such as an optical sensor or a microswitch, which detects passage of the sheet S. The stop of the rotation drive and the release of the states of the pre-shift roller 1 and the offset roller 2 are controlled.

In the sheet conveying apparatus having the above configuration, FIG.
The operation will be described in the order of (a) to (d). First, the sheet S is conveyed from the conveying roller 57 to the pre-shift roller 1, and this step is the same as in the conventional sheet conveying apparatus. In this case, the sheet S conveyed by the pre-shift roller 1 has reached the offset roller 2. Since the offset roller 2 is formed in the shape of a truncated cone as described above, the leading end of the sheet moves slightly to the right as shown in FIG. It comes into contact with the roller 3.

At this stage, the post-shift roller 3 is stopped, and the sheet S is conveyed until the entire leading edge of the sheet S comes into contact with the post-shift roller 3 as the offset roller 2 continues to rotate. As shown in the drawing, a bend B occurs in the sheet S at a position near the left side indicated by oblique lines.

An optical sensor (not shown) is provided between the roller 2c and the post-shift roller 3, and when the optical sensor detects that the entire front end portion of the sheet S has come into contact with the roller 3, the control device detects it. The signal is input and the rotation of the roller 3 is started. Note that, although the roller 3 is stopped, even if the roller 3 is rotated at a lower speed than the roller 2, the sheet S can be bent by the speed difference.

After the sheet is bent, the roller 3
, The center line of the sheet shifts from the position A1 to the position A2, and is offset while being conveyed in the direction A, as shown in FIG. FIG. 3 is a perspective view showing the above state. As described above, since the offset is performed using the bending B of the sheet S, a known technique can be applied to the driving mechanism of each roller, and the tension is not uniformly applied to the sheet S, the corner is bent without complicating the structure. Damage can be prevented.

In the above-described steps shown in FIGS.
When the sheet S is conveyed at a relatively high speed, a paper jam may occur before the bending B is formed. Therefore, when performing the offset, the conveying speed is limited. There is a need. However, lowering the transport speed undesirably leads to a reduction in the processing speed of the entire printing process. Further, there may be a case where the user does not need the offset and wants to print immediately.

Therefore, it is possible to select whether or not to perform the offset. If the offset is to be performed, the above-described sheet conveyance mode is selected. Roller 1
The above-mentioned problem can be solved by switching to a mode in which the sheet S is directly conveyed to the roller 3 after the shift. Further, according to the above configuration, it is possible to convey the sheet while changing the position of the sheet in the conveying direction.
It is also possible to differentiate the stacking position for each copy or job by making the stacking position different.

In order to realize a mode in which the sheet S is directly conveyed from the pre-shift roller 1 to the post-shift roller 3, the distance from the center of the pre-shift roller 1 to the center of the post-shift roller 3 must be the minimum of the sheet S. What is necessary is just to make it narrower than length (with respect to the conveyance direction of the sheet S), and the conveyance of the sheet without offset can also be easily realized.

In FIG. 2, when the offset roller 2 once holds the sheet S, the sheet S is conveyed by the pre-shift roller 1 and the offset roller 2, respectively. On the other hand, since the conveying direction of the sheet S is different in the offset roller 2, the sheet S may be wrinkled due to uneven tension.

To solve such a problem, FIG.
When the offset roller 2 is in the holding state at the stage, the control may be performed such that the pre-shift roller 1 is in the releasing state. Whether or not the offset roller 2 is in the holding state can be easily confirmed by the conveying speed of the sheet S.

[Second Embodiment] FIG. 4 is a top view showing a sheet conveying apparatus according to a second embodiment. In the present embodiment, the disposition posture of the offset roller 2 is changed, and furthermore, bending is formed at two places between the roller 1 before the shift and the offset roller 2 and between the offset roller 2 and the roller 3 after the shift. The other configuration is the first
This is the same as the embodiment.

That is, the offset roller 2 has the same roller shape as that of the first embodiment, but the rotation shaft 2a
Is different from the first embodiment in that it is installed at an angle to the transport direction. In addition, by controlling the rotation of the offset roller 2 and the post-shift roller 3 in accordance with the conveyance of the sheet, a bend is formed at a position different from left to right on the leading end side of the sheet S upstream of each roller.

The operation of the sheet conveying apparatus having the above-described structure will be described. First, in the stage of FIG. 4, the sheet S is conveyed by the pre-shift roller 1 and the conveying roller 57, but at this time, the roller 2 does not rotate. It has been stopped.

When the sheet S is conveyed by the roller 1,
The leading end of the sheet S first comes into contact with the right roller 2c, but since the roller 2 is in a stopped state, a rightward bending C shown by oblique lines is generated. When the optical sensor detects that the sheet S has reached the entire area of the roller 2, the rotation of the roller 2 is started, and the subsequent state is obtained. (Except that there is bending between the two), and the description is omitted.

As described above, in the present embodiment, not only the deflection between the pre-shift roller 1 and the offset roller 2 but also the deflection between the offset roller 2 and the post-shift roller 3 is used to move the sheet S from the position A1 to the position A2. The roller can be transported in an offset manner.
Since a is inclined with respect to the transport direction, the offset amount can be further increased as compared with the case of FIG.

Although the shape of the offset roller 2 is a truncated cone here, the rotary shaft 2a of the offset roller 2 is inclined, so that there is no problem even if the shape of the offset roller 2 is cylindrical. However, when the rotating shaft 2a of the offset roller 2 is orthogonal to the transport direction, the shape of the offset roller 2 needs to be a truncated cone.

[Third Embodiment] FIG. 5 is a top view showing a sheet conveying apparatus according to a third embodiment. In the present embodiment, the pre-shift roller 1 is
Is switched between a first position in which the sheet S transferred from the first position is conveyed while being offset and a second position in which the sheet S is conveyed as it is, and other configurations are the same as those of the first embodiment. ing.

That is, in this embodiment, the offset roller 2 has the left and right rollers 2b and 2c formed in the same columnar shape and the same shape as the pre-shift roller 1 and the post-shift roller 3, and the rollers 1, 2 and The rotary shafts 1a, 2a, and 3a are arranged in parallel with each other so as to be orthogonal to the transport direction A. Rotary axis 2 of offset roller 2
a is supported movably in the axial direction,
Is set to take a second posture in which the sheet S delivered from the pre-shift roller 1 is transported to the post-shift roller 3 as it is in a normal state. Further, a switching means for switching the attitude of the offset roller 2 is provided.

The switching means may be any as long as it allows the offset roller 2 to move in the axial direction. For example, a rail is laid in parallel with the rotation shaft 2a of the roller 2, and a pulley is further parallel to the rail. A belt driven by the above rotation is also provided, and the bearing of the rotating shaft is slidably mounted on the rail. When the bearing is fixed to the belt, a configuration is possible in which the roller 2 can be moved in the axial direction together with the bearing by driving the belt. Further, a ball screw, an air cylinder, or a solenoid may be used instead of the belt.

The operation of the conveying device having the above-described configuration will be described with reference to FIG. 5. First, the rollers 1 and 2 are driven to convey the sheet S, and the leading end of the sheet S is nipped by the roller 2. Then, the optical sensor (not shown) recognizes the sheet S and stops the roller 2. As a result, the sheet S is held between the rollers 2, and when only the roller 1 is continuously driven in this state, the sheet S is bent as shown in FIG.

After the deflection E is formed on the sheet S, the roller 2 is moved in the direction perpendicular to the conveying direction A by the attitude switching means as described above, and
Is rotated, the sheet S is conveyed to the roller 3 in an offset state without causing damage, as shown in FIG. As for the timing for operating the attitude switching means, the sheet S may be recognized by an optical sensor or the like as described above, and may be controlled so as to be activated after waiting for a certain time by a timer.

According to the above configuration, the offset roller 2
Receives the sheet S in the second position in which the sheet is conveyed in the same direction as the conveying direction of the pre-shift roller 1, and is switched to the first position when the sheet S is bent, so that the first and second positions are used.
It is possible to more reliably prevent the sheet from being broken or habited as compared with the sheet conveying apparatus according to the embodiment, and to further reduce the shift of the sheet S in the conveying direction of the sheet S after the shift.

[Fourth Embodiment] FIG. 6 is a top view showing a sheet conveying apparatus according to a fourth embodiment. In the present embodiment, in order to offset the sheet S without forming a bend, two sets of offset rollers in which the right and left rollers have a truncated cone shape as used in the first embodiment are combined. High-speed conveyance is possible while controlling the conveyance roller 57, the first offset roller 2, and the second offset roller 4 to release the holding state in accordance with the conveyance of the sheet S.
This is the same as the embodiment.

That is, in the present embodiment, the second offset roller 4 having a frustoconical roller is disposed between the first offset roller 2 similar to the first embodiment and the post-shift roller 3. . Rotary shaft 4a of this roller 4
Is installed so as to be inclined with respect to the rotation axis of the other rollers, and the arrangement of the left and right rollers 4b and 4c is opposite to that of the roller 2, so that the rollers 2 and 4 work in pairs. Has become.

The rotation axis 2a of the roller 2 is in the same direction as the pre-shift roller 1, but the inclination of the rotation axis 4a of the roller 4 depends on the truncated cone shape of the offset roller 4 and the distance from the rotation axis 2a of the roller 2. Set related. The position of the roller 4 may be set so that the sheet S can be returned to the sheet conveying direction A as a post-process after the sheet S is conveyed by the roller 2. S can be transported.

As described above, as the releasing means for bringing each roller from the holding state to the releasing state, it is possible to adopt a configuration in which one of a pair of upper and lower rollers is installed so as to be vertically movable by an air cylinder.

The operation of the sheet conveying apparatus having the above structure will be described with reference to FIG. 6. First, the sheet S is conveyed from the pre-shift roller 1, and the leading end of the sheet S is held by the roller 2. At the same time, the holding state of the sheet S on the rollers 1 and 57 is released. Thus, the sheet S is transported while the transport direction is switched. The holding state can be released by recognizing the sheet S by an optical sensor or the like installed near the downstream side of the roller 2 and sending a detection signal to the control device.

After the sheet S reaches the roller 4, the entire end portion of the sheet S is held by the roller 4, and at the same time, the holding state of the roller 2 is released. by this,
While the sheet S is switched in the reverse direction, the leading end of the sheet S reaches the roller 3 at the same time as the left and right sides, and the transport direction is returned to the same direction A as the transport direction of the roller 1 as shown in FIG.

Then, the sheet S is offset and conveyed by releasing the holding state of the roller 4 at the same time as the leading end of the sheet S is held and conveyed by the roller 3. As a result, a time lag for forming a bend in the sheet S is eliminated, high-speed conveyance is enabled, and a delay in print processing time can be prevented.

[0087]

As is apparent from the above description, according to the present invention, immediately before reaching the second conveying means for conveying a sheet in a direction different from that of the first conveying means, or from the second conveying means. By forming a bend in at least one of the following transport means, it is possible to change the transport direction without applying unnecessary force to the sheet without damaging the sheet, and to prevent the sheet from being damaged or damaged. The occurrence of rubbing marks by the rollers can be prevented. Furthermore, the structure of the transport device itself is not complicated, and an inexpensive device can be provided.

Further, there are provided a plurality of conveying means for conveying the sheet, the most upstream conveying means and the most downstream conveying means are set so as to convey the sheet in the same direction, and the intermediate conveying means are respectively set in different directions. By adopting a configuration in which the sheet is conveyed and the sheet is offset while conveying the sheet by each conveying means, high-speed conveyance can be performed while the sheet is offset.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an overall configuration of an image forming apparatus on which a sheet conveying device is mounted.

FIG. 2 is a top view illustrating the first embodiment of the sheet conveying apparatus.

FIG. 3 is a perspective view showing the arrangement of rollers according to the first embodiment.

FIG. 4 is a top view illustrating a second embodiment of the sheet conveying apparatus.

FIG. 5 is a top view illustrating a third embodiment of the sheet conveying apparatus.

FIG. 6 is a top view showing a fourth embodiment of the sheet conveying apparatus.

[Explanation of symbols]

 1 roller before shift 2 offset roller 3 roller after shift

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Heicho Yamamoto 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka F-term (reference) 3F102 AA06 AB01 BA06

Claims (10)

[Claims] A plurality of transporting means for transporting a sheet, wherein at least one of the transporting means is an offset transporting means set to transport the sheet in a direction different from that of the other transporting means; A sheet conveying apparatus provided with a bend forming unit for forming a sheet bend between a conveying unit and a conveying unit adjacent thereto. 2. A first conveying means for conveying a sheet in a predetermined direction, and a first conveying means disposed downstream of the first conveying means for conveying the sheet.
A second conveying unit that conveys the sheet in a direction different from the sheet conveying direction of the conveying unit; and a second conveying unit that is disposed further downstream in the conveying direction and transfers the sheet conveyed by the second conveying unit to the first conveying unit. A third conveying unit that conveys the sheet in the same direction as the sheet conveying direction; and a bending forming unit that forms a bending of the sheet between the second conveying unit and the third conveying unit. 3. The sheet conveying device according to claim 3, wherein the conveying unit conveys the sheet in a state where the bending is formed by the bending unit and offsets the sheet. 3. A first conveying means for conveying a sheet in a predetermined direction, and a first conveying means disposed downstream of the first conveying means for conveying the sheet.
A second conveying unit that conveys the sheet in a direction different from the sheet conveying direction of the conveying unit; and a second conveying unit that is disposed further downstream in the conveying direction and transfers the sheet conveyed by the second conveying unit to the first conveying unit. A third sheet conveying means for conveying the sheet in the same direction as the sheet conveying direction, and a first sheet forming means for forming sheet bending between the first sheet conveying means and the second sheet conveying means. The second transporting means and the third
A second bend forming means for forming a bend between the first and second convey means, and the second and third convey means convey a sheet in a state where the bend is formed by the bend forming means, and A sheet conveying device for offsetting. 4. The apparatus according to claim 2, wherein the second conveying means is switchable between a holding state when conveying the sheet and a releasing state in which the sheet does not act on the sheet, and is released when the sheet is not offset. Or the sheet conveying device according to 3. 5. The distance between the first transport means and the third transport means is smaller than the length of the sheet in the transport direction.
The sheet conveying device as described in the above. 6. A first conveying means for conveying a sheet in a predetermined direction, and a second conveying means arranged in parallel on the downstream side of the conveying means.
The second transporting means is movable in a direction orthogonal to the transporting direction, and forms a bend in the sheet between the first transporting means and the second transporting means. The driving of the first and second conveying means is controlled such that the conveying speed of the first conveying means is lower than the conveying speed of the second conveying means. A sheet conveying device for offsetting the sheet by moving the second conveying means. 7. The first conveying means is switchable between a holding state when conveying the sheet and a release state in which the first conveying means does not act on the sheet, and is in a released state when the second conveying means conveys the sheet. 7. The sheet conveying device according to claim 2, wherein: 8. A printing apparatus comprising a plurality of conveying means for conveying a sheet, wherein the most upstream conveying means and the most downstream conveying means are set so as to convey the sheet in the same direction, and the intermediate conveying means comprises:
A sheet conveying apparatus which is set so as to convey a sheet in different directions, and offsets while conveying the sheet by each conveying means. 9. A first transport unit for transporting a sheet in a first direction, and a downstream side of the first transport unit for transporting a sheet from the first transport unit in a second direction. A second transport unit that transports the sheet from the first transport unit to a third direction different from the second direction. A third transport unit, a fourth transport unit disposed downstream of the third transport unit for transporting the sheet in the same direction as the first direction;
The second transporting means and the third transporting means.
Wherein the conveying means conveys the sheet while shifting the sheet in a direction orthogonal to the first direction to offset the sheet. 10. The first, second, and third conveying means are switchable between a holding state of a sheet and a release state in which the sheet does not act on the sheet, and each of the conveying means on the downstream side conveys the sheet. The sheet conveyance device according to claim 9, wherein the sheet conveyance device is in a release state.