JPH1179477A - Laterally paper sheet correcting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly performing the positional correction of a paper sheet in lateral direction while suppressing deflection from occurring for smooth feeding of the paper sheet. SOLUTION: A correction mechanism is structured so that a guide member 16 is disposed along a paper sheet feeding path 10, and a sheet P is fed aslant by a slanted roller 20 until it is brought in contact with the guide surface 16a of the guide member 16 so as to correct a paper sheet position in lateral direction of the paper sheet feeding path 10. Also the slanted roller 20 is driven at least while the sheet passes the slanted roller 20. In addition, a pair of feeding rollers 14 disposed on the downstream side of the slanted roller 20 is structured so that it can be switched over between a pressing condition and a nonpressing condition. It is set at the nonpressing condition until the positional correction of the paper sheet P is completed and, based on the detection of completion of the positional correction by a sensor 34, it is switched over to the pressing condition. The pair of feeding rollers 14 are disposed so that the top end part of the paper sheet P can be nipped when the nonpressing condition is switched over to the pressing condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper width direction correcting mechanism applied to an image forming apparatus such as a copying machine and a printer.

[0002]

2. Description of the Related Art Conventionally, as a paper width direction correcting mechanism as described above, for example, there is a mechanism disclosed in Japanese Patent Application Laid-Open No. 7-89645.

In this mechanism, a side guide is provided along a paper transport path, and a skew roller is provided corresponding to the side guide. Then, the fed sheet is skewed and conveyed by the skew roller, so that the side portion of the sheet comes into contact with the side guide, and the position of the sheet in the sheet conveyance path in the width direction is corrected, that is, in the direction orthogonal to the conveyance direction. Is corrected.

In this mechanism, the skew roller can be displaced between a driving position in contact with the sheet and a retracted position separated from the sheet, and the skew roller is located upstream of the skew roller (upstream in the sheet conveyance direction). Is configured to be switchable between a pressurized state in which a pair of conveying rollers disposed in a position close to the sheet Nipping the sheet and a non-pressurized state (conveying state and non-conveying state). Then, when feeding the paper, the transport roller pair is set in a pressurized state, the paper is transported by the transport roller pair, and the sensor detects that the leading end of the paper has reached a position corresponding to the skew roller. Then, the skew roller is set to the driving position, and the pair of conveying rollers is set in a non-pressurized state. When it is detected that the paper position correction has been completed,
The skew roller is reset to the retracted position, and the conveying roller pair is switched to a pressurized state. Thereafter, the sheet is conveyed downstream by driving the conveying roller pair.

[0005]

In the above-mentioned conventional paper width direction correcting mechanism, the skew roller can be displaced between the drive position and the retreat position as described above, and when the position correction of the paper is completed, the skew roller is displaced. Is reset to the retracted position, so that the skew force by the skew rollers does not act more than necessary on the sheet whose position has been corrected. Therefore, there is a characteristic that the sheet hardly bends while the sheet is skewed and abutted on the side guide.

However, since the skew roller is immediately moved to the retracted position after the position correction, there is a possibility that the sheet once corrected is shifted in the width direction again. Therefore, position correction cannot be performed appropriately.

Further, after the position correction, the sheet is conveyed only by the pair of conveying rollers disposed on the upstream side of the skew roller in the conveying direction, so that there is a problem that a conveyance failure is likely to occur. That is, after the position is corrected, the sheet is in contact with the side guide, so that conveyance resistance is generated due to friction. However, when the sheet is conveyed by the conveying roller pair as described above, mainly the rear end portion of the sheet ( Since the paper is conveyed while nipping at the rear end portion in the traveling direction), the conveyance on the leading end side of the paper tends to be stagnant due to the friction and the gradient of the paper conveyance path, and a conveyance failure is easily induced.
Therefore, it is necessary to improve the paper after the position correction so that the paper can be transported more smoothly.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. The present invention has been made in consideration of the above-described problems. It is intended to provide a direction correction mechanism.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a reference member installed in a paper transport direction along a paper transport path, and skews the paper with respect to the transport direction. A skew roller, wherein the skew roller causes the sheet to abut on a reference member and corrects the position of the sheet in the width direction of the sheet conveyance path, in a sheet width direction correction mechanism in which the sheet can be conveyed. A transport roller pair that can be switched to a non-transport state is provided downstream of the skew roller in the transport direction, and a detection unit that detects that the position of the paper has been corrected is provided. The conveying roller pair is held in a non-conveying state, the skew roller is driven with respect to the sheet while at least each sheet passes through the skew roller, and the conveyance is performed based on detection of completion of correction by the detection unit. It is obtained to switch the conveyance state over roller pair (claim 1).

According to this mechanism, the skew roller is driven until the sheet passes through the skew roller. Therefore, after the side of the sheet in the traveling direction abuts the reference member, that is, after the position correction is completed. Also, the skew force is continuously applied to the sheet. Therefore, the sheet does not separate from the reference member. In addition, after the position correction, the pair of transport rollers disposed downstream of the skew roller is switched to the transport state, and the sheet is pulled downstream in the transport direction (that is, a transport force is applied). Therefore, a force in a direction in which the conveying force of the conveying roller pair and the skew force of the skew roller are combined, that is, a force in a direction parallel to the conveying direction acts on the sheet. As a result, the skew force acting on the sheet is reduced, and the sheet is hardly bent.

After the position correction, the skew roller and the pair of transport rollers downstream thereof are driven. Therefore, after the position correction, the skew roller is retracted and the sheet is fed only by the upstream pair of transport rollers. As compared with this type of apparatus, the conveying force can be applied to the leading end side of the sheet. For this reason, the paper can be smoothly transported without being delayed at the leading end.

In the above mechanism, the pair of transport rollers may be arranged so that the leading end portion in the traveling direction of the sheet can be nipped when switching from the non-transport state to the transport state. 3) The transport force is reliably applied to the leading end of the paper, and the paper can be transported more smoothly.

[0013]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a paper conveying path of a copying machine to which the paper width direction correcting mechanism of the present invention is applied, for example, upstream of a registration roller pair for aligning the leading edge of the paper, ie, upstream in the paper conveying direction. Side view.

In the sheet conveying path 10 shown in FIG. 1, a pair of conveying rollers 12, 1 are sequentially arranged from the upstream side in the sheet conveying direction.
A guide member 16 (reference member) having a guide surface 16a parallel to the transport direction is provided between the transport roller pairs 12 and 14. The guide member 16 is disposed near one end (in the vicinity of the front end in FIG. 1) in the width direction of the paper conveyance path 10, that is, in the direction orthogonal to the conveyance direction on the paper conveyance surface.

A skew roller 20 for skew-transporting the sheet toward the guide member 16 is provided at a position closer to the center of the sheet conveying path 10 than the guide member 16.
Are arranged. The skew roller 20 is attached to a mounting member 22.
And is mounted on the frame of the copying machine via the mounting member 22 such that the roller 20 is in contact with the sheet. The rotating shaft 21 of the skew roller 20 is connected to a driving shaft 24 supported by the frame via a universal joint 26 as shown in FIG. The drive shaft 24 is connected to a drive motor via a torque transmission unit such as a gear (not shown) so that the skew roller 20 rotates by receiving the rotation drive force of the drive motor. Has become.

The transport roller pairs 12 and 14 are both for nipping and transporting a sheet by a pair of upper and lower rollers.
Of the transport roller pairs 12, 14, the downstream transport roller pair 14, in particular, although not shown, has a configuration in which one roller can contact and separate from the other roller.
In response to the driving of a solenoid (not shown), the two rollers can be switched between a pressurized state in which they are pressed against each other (transport state) and a non-pressurized state in which they are separated from each other (non-transport state).
In a pressurized state, the paper is nipped and conveyed by both rollers, while in a non-pressurized state, the rollers are separated to such an extent that the paper can pass between the rollers.

The position of the transport roller pair 14 is set, for example, such that when the position correction of the sheet is completed, the leading end portion of the sheet (the leading end portion in the traveling direction of the sheet) can be nipped. Such a position is experimentally determined by, for example, repeatedly transporting a large number of sheets and knowing the tendency of the sheet leading end position when the position correction is completed.

In the drawing, reference numerals 30, 32, and 34 denote paper detection sensors embedded in the transport surface, respectively. The sensors 30, 32 are located at the center of the paper transport path 10 in the width direction, respectively. The sensor 34 is disposed on the downstream side of the conveyance roller pair 14 and is located on the upstream side of the conveying roller pair 14.
6a. Thus, while the position of the sheet in the transport direction is detected based on the sheet detection by the sensors 30 and 32, it is detected that the position of the sheet is corrected in the width direction based on the sheet detection by the sensor. It has become. That is, when the position in the width direction of the paper is corrected in the paper transport path 10, the guide surface 16
Since the sheet a is in contact with the sheet a, the sensor 34 disposed along the guide surface 16a detects the sheet so that the correction of the position of the sheet can be detected. That is, the sensor 34 constitutes the detecting means of the present invention.

These sensors 30, 32, and 34 are, for example, reflection type sensors, and are configured to detect the presence or absence of a sheet by reflecting irradiated light on a sheet and receiving the light. During the operation of the copying machine, the sensors 30, 32 are used.
The timing of the operation of the skew roller 20 is determined based on the detection of the sheet by the sensor, and the state switching timing of the pair of transport rollers 14 based on the detection of the sheet by the sensor 34, that is, the state of the transport roller pair 14 is changed from the non-pressurized state. The timing for switching to the pressurized state is provided.

The sensor 32 disposed downstream of the transport roller pair 14 detects the leading edge of the sheet at a position where the trailing end of the sheet has completely passed the skew roller 20 in relation to the sheet. It is arranged in.

Next, the operation of correcting the position of a sheet in the sheet transport path 10 configured as described above will be described with reference to the timing chart of FIG.

In the paper transport path 10, the paper P is
On the upstream side of the transport roller pair 12, the paper is sent in a direction indicated by a white arrow in FIG. At this time, the transport roller pair 14 is in a non-pressurized state, and the skew roller 20 is stopped. The transport roller pairs 12 and 14 are constantly driven to rotate while the paper P is being transported.

First, when the sheet P passes through the transport roller pair 12 and its leading end is detected by the sensor 36 (t1).
At this point, the rotational driving force of the drive motor is transmitted to the skew roller 20 according to the operation of a solenoid (not shown).

When the sheet P is further conveyed and its leading end reaches the skew roller 20, the sheet P is fed by the conveying roller pair 12 and the skew roller 20, and the skew force of the skew roller 20 is reduced. The sheet P acts to guide the member 16
Skewed toward. As a result, the side of the sheet P comes into contact with the guide surface 16a to be aligned with the guide surface 16a, and the width direction position of the sheet P in the sheet transport path 10 is corrected as shown in FIG.

When the position correction of the sheet P is completed,
That is, when the sheet P is detected by the sensor 34 (time t2), the transport roller pair 14 is switched from the non-pressurized state to the pressurized state, and the leading end portion of the paper P is nipped by the transport roller pair 14. As a result, the paper P is sent to the downstream side by the drive of the transport roller pair 14 and the skew roller 20. Note that the leading end of the paper P is
When the position of the sheet P has not been corrected in the state where the sheet P has reached 4, the skew roller 20 feeds the leading edge of the sheet P further downstream between the rollers of the pair of transport rollers 14 and skews the sheet P. Will be performed.

When the sheet P is conveyed in this way and the leading end thereof is detected by the sensor 32 (at time t3), the skew roller 20 is stopped, and the sheet P is further conveyed and the sheet P passes through the sensor 32. Then (at time t4), the transport roller pair 14 is switched to the non-pressurized state in synchronization with this.

According to the above configuration, regardless of whether or not the position correction of the sheet P is completed, the sheet P is completely
Skew roller 20 is driven until it passes. Therefore, the skew force of the skew roller 20 always acts on the paper P, and the state where the side of the paper P is completely in contact with the guide surface 16a, that is, the position after the position correction is maintained. In this state, the sheet P is transported downstream.

Therefore, there is no danger that the sheet whose position has been corrected will be shifted again, unlike a conventional mechanism of this type in which the skew roller is immediately moved to the retracted position immediately after the position of the sheet is corrected. The position correction in the width direction in the sheet transport path 10 is reliably performed.

Further, after the position correction, the conveying roller pair 14 is switched to the pressurized state as described above, and the conveying force is applied to the sheet P by the conveying roller pair 14.
Even if the skew roller 20 is continuously driven as described above, the sheet P is hardly bent.

That is, a combined force of the conveying force of the conveying roller pair 14 and the skew force of the skew roller 20, that is, a force in a direction more parallel to the conveying direction acts on the sheet P after the position correction. As a result, the skew force acting on the sheet P is reduced. Therefore, after the position correction, the skew roller 20 is driven as described above to correct the corrected sheet P.
Is securely held, but the sheet P hardly bends.

In addition, after the position correction, the transport roller pair 14
Since the sheet P is transported by the skew roller 20 and the skew roller 20, after the position correction, the skew roller is retracted and compared with a conventional apparatus of this type in which the sheet is transported only by the pair of transport rollers on the upstream side. A larger conveying force can be applied, and a conveying force can be applied to a portion of the sheet P closer to the leading end. Therefore, after the position correction, the paper P can be transported extremely smoothly without any delay in the transport at the leading end side of the paper.

Therefore, according to the configuration of the paper transport path 10 as described above, while the position correction in the paper width direction is reliably performed, the paper P can be transported smoothly while suppressing the deflection.

The paper transport path described in the above embodiment is one embodiment of the paper transport path to which the paper width direction correcting mechanism of the present invention is applied, and the specific configuration of the paper transport path and the paper transport path The specific configuration of the width direction correcting mechanism can be appropriately changed without departing from the gist of the present invention.

For example, in the above embodiment, when the position correction of the paper P is completed, the transport roller pair 14 is arranged so as to be able to nip the front end portion of the paper P in the traveling direction. It is not necessary to arrange so as to nip the portion, and it is downstream of the skew roller 20 and
At least while the skew roller 20 is being driven, the pair of transport rollers 14
May be arranged. However, the sheet P after the position correction has a conveyance resistance due to the contact friction with the guide member 16 and the conveyance tends to be delayed at the leading end side of the sheet P. Paper P
It is preferable to arrange the transport roller pair 14 so that the leading end portion can be nipped. In this way, the paper P can be smoothly transported even when the paper transport path 10 has an ascending gradient in addition to the friction with the guide member 16.

In the above-described embodiment, the sheet P is detected by the single sensor 34. However, for example, two sensors are arranged separately along the guide surface 16a, and the two sensors are used. The completion of the position correction of the sheet P may be detected based on the detection of the sheet P. In this way, by detecting any two points on the side of the sheet P, it is possible to reliably detect the state in which the side of the sheet P abuts on the guide surface 16a from the front end to the rear end. It is possible to more accurately detect a state where the position correction is completed.

In the above embodiment, an example is described in which the paper width direction correction mechanism of the present invention is applied to a copying machine. However, the mechanism of the present invention is applicable to an image forming apparatus other than a copying machine, such as a printer or a facsimile. Of course, it is also applicable.

[0038]

As described above, the present invention relates to a paper width direction correcting mechanism in which a sheet is brought into contact with a reference member by a skew roller to correct the width of a sheet being conveyed in the width direction. Since the skew roller is driven with respect to the sheet at least while each sheet passes through the skew roller, the position of the corrected sheet can be reliably maintained. In addition, before the position correction, the conveying roller pair on the downstream side of the skew roller is set to the non-conveying state, and the position is switched to the conveying state simultaneously with the completion of the position correction. The bending force of the sheet can be suppressed by effectively reducing the running force, and the sheet can be conveyed while applying a conveying force to the leading end side of the sheet. Accordingly, while the position correction in the sheet width direction is appropriately performed, the sheet can be transported smoothly while suppressing the occurrence of the bending.

In particular, when switching from the non-conveying state to the conveying state, if the conveying roller pair is arranged so that the leading end portion in the traveling direction of the paper can be nipped,
Because a conveying force can be applied to the leading edge of the paper,
Paper can be transported more smoothly.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing a sheet conveying path of a copying machine to which a sheet width direction correcting mechanism according to the present invention is applied.

FIG. 2 is a timing chart illustrating a sheet position correcting operation.

FIG. 3 is a schematic diagram illustrating position correction in the width direction of a sheet.

[Explanation of symbols]

 Reference Signs List 10 paper transport path 12, 14 transport roller pair 16 guide member 16a guide surface 20 skew roller 30, 32, 34 sensor P paper

Claims (2)

[Claims] 1. A reference member provided in a sheet conveying direction along a sheet conveying path, and a skew roller for skewing the sheet with respect to the conveying direction. In the paper width direction correction mechanism for correcting the position of the paper in the width direction of the paper conveyance path by contacting the conveyance roller pair with a conveyance roller capable of switching between a conveyance state in which the paper can be conveyed and a non-conveyance state, a skew roller And a detecting unit for detecting that the position of the sheet has been corrected.When conveying the sheet, the conveying roller pair is held in a non-conveying state, and at least each sheet is While passing through the skew roller, the skew roller is driven with respect to the sheet, and the transport roller pair is switched to the transport state based on detection of completion of correction by the detection means. Paper width direction correction mechanism. 2. The sheet width direction according to claim 1, wherein the transport roller pair is arranged so as to be able to nip the leading end portion in the traveling direction of the sheet when switching from the non-transport state to the transport state. Correction mechanism.