JPH04260558A - Sheet position compensating device - Google Patents

Abstract

PURPOSE:To transversely move a sheet to a register roller device positioned just before an image transfer section in an image forming device, in such a condition that the leading end part of the sheet is nipped, and to allow the aligning mechanism to surely align the sheet. CONSTITUTION:A roller device composed of a register roller device 10 and a preregister roller device 20 and a gate member 6 are provided to a frame 2 of a sheet aligning device 1 which is provided to a toner image forming section such as a photosensitive drum in an image forming device, just before an image transfer part. In the above-mentioned sheet aligning device, a mechanism 30 for moving the register roller device, perpendicular to a sheet conveying direction, is provided so as to transversely move the register roller device in accordance with detection data for the side part of a sheet by a sheet sensor. Further, an engaging member 31 is provided in order to position a drive roller 11 and a pinch roller opposed to the roller 11 in the register roller device, thereby the positioning of the upper and lower rollers can be easily made during closing of the upper frame of the image forming device from a swing-up opening condition.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper positioning device disposed immediately before an image recording section in an image forming apparatus such as a copying machine or a printer. The present invention relates to a device that, when a positional deviation occurs with respect to a line, corrects the positional deviation and allows the sheet to be sent out toward an image transfer unit while being aligned with a reference line.

0002

[Prior Art] In image forming apparatuses using electrophotography such as electronic copying machines and laser printers, a toner image is formed on an image carrier such as a photoreceptor drum, the toner image is transferred to paper, and then fixed. A means is used to create a copy by performing a fixing action through a device. In the image forming apparatus, a gate member and a registration roller member are disposed immediately before the image transfer section, and the gate member temporarily stops the paper being conveyed in the paper path so that the paper is formed on the photoreceptor. With respect to the toner image, the gate is opened with the leading end of the paper positioned, and the registration roller device feeds the paper at a constant speed to transfer the image from the photoreceptor.

[0003] In a paper conveyance device having the above-mentioned configuration, the paper being conveyed through the paper path may deviate slightly from the reference line of the paper path. The paper misalignment problem is not a big problem if the copy mode for the paper is single-sided copying, but in the case of color copying or multiple copying, when images are transferred in an overlapping state, This poses a problem in that images are misaligned and defective copies are created. Therefore, for example,
As shown in Publication No. 2-203149, etc., for a paper temporary stop member disposed immediately before the image transfer section,
It has been proposed to provide a means for laterally moving the paper to eliminate misregistration of the paper.

In the paper position correction device shown in the conventional example, a registration roller device is provided in a horizontally movable manner upstream of the gate member in the paper conveyance direction, and means for detecting paper misalignment is arranged in the paper path. are doing. Then, with respect to the paper stopped by the gate, the registration roller device is moved in a direction to correct the misalignment of the paper, and the paper is sent out toward the image transfer unit with the side of the paper aligned with the reference line. There is.

[0005]

[Problems to be Solved by the Invention] In commonly used image forming apparatuses, an upper frame equipped with an image forming member such as a photoreceptor is separated from a paper path part with respect to a lower frame equipped with a paper feeding device. It is structured so that it opens in the shape of an alligator mouth. However, in the image forming apparatus, when the upper frame is closed after opening the upper frame to release the paper path and performing work such as removing jams on paper stopped in the paper path, There is a problem in that it is difficult to accurately align the drive roller of the registration roller device and the pinch roller. Additionally, if registration is performed on the paper while both rollers of the registration roller device are misaligned, the moving action will not be performed accurately when the registration roller device moves the paper laterally. There's a problem. In the conventional paper position correction device, there is a problem in that the registration position alignment function is not performed well, especially when registration is performed on thick paper.

In addition to the above problem, when the paper is moved in the width direction of the paper path by the registration roller device, the pre-registration roller device disposed upstream of the registration roller device remains in a state where the rear part of the paper is nipped. However, after the paper is laterally moved by the registration roller device, depending on the stiffness of the paper, the registration roller device may move in the return direction, resulting in an error in the registration position. but,
The apparatus shown in the conventional example does not have a means to deal with such a problem, and depending on the conditions such as the thickness of the paper, after the registration is performed once by the registration roller device,
There is a problem in that the paper is misaligned, resulting in a defective copy in which the transferred image is misaligned.

[0007]

OBJECTS OF THE INVENTION The present invention eliminates the drawbacks of the conventional paper position correction device as described above, and enables accurate positioning of the upper and lower rollers of a registration roller device. It is an object of the present invention to provide a device that allows the device to perform sheet registration without being affected by conditions such as paper quality.

[0008]

[Means for Solving the Problems and Effects] The present invention provides an upper frame on which an image forming member such as a photoreceptor is disposed, with respect to a lower frame on which a paper feeding member is mounted, with a paper conveyance path portion as a boundary. In an image forming apparatus configured to be openable and closable in an alligator shape, means for positioning the leading edge of the paper is disposed immediately before the image transfer section from the photoreceptor, and the paper positioning means allows the paper to be moved. The present invention relates to an apparatus configured to temporarily stop the paper and feed the paper in accordance with an image formed on a photoreceptor.

In the present invention, the paper temporary stopping means is composed of a gate member, a registration roller device disposed downstream of the gate member, and a pre-registration roller device disposed upstream of the gate. a paper position detection member disposed at a position corresponding to a reference line for paper conveyance, and a means for mutually positioning a drive roller and a pinch roller with respect to the registration roller device,
The paper is nipped between the rollers of the upper and lower roller devices, and means is provided for moving the paper laterally with the paper sandwiched between the upper and lower rollers, and the paper is moved from the paper position detection member to The paper is configured to be moved in the horizontal direction according to the signal.

Further, in the present invention, the pinch roller of the registration roller device is provided with means for applying a pressing force to the drive roller, and the pressing means includes a means for sliding the shaft of the pinch roller in the axial direction. Possible members can be provided. Further, in the present invention, the pre-registration roller device disposed upstream of the registration roller device is provided with a means for releasing the nip on the paper, and when the registration roller device aligns the paper, the nip of the paper in the pre-registration roller device is released. can do.

With the above-described configuration, the registration roller device of the present invention is provided with an alignment mechanism for the upper and lower rollers, so that the positioning of the upper and lower rollers can be easily adjusted when the upper frame opened in the shape of an alligator mouth is closed. The operation can be performed accurately, and the upper and lower rollers of the registration roller device can be moved laterally in conjunction with each other. Further, when registering the sheets in a state where they are nipped by the registration roller device, it is possible to release the nip caused by the pre-registration roller device, so that the sheets can be aligned in a good condition.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS A paper position correction device of the present invention will be described with reference to the illustrated example. A paper alignment device 1 of the present invention shown in FIG. 1 is disposed immediately before a portion of an image forming apparatus such as an electronic copying machine where a toner image is transferred from a photoreceptor, and includes a registration roller device 10 and a gate member. 6 and a pre-registration roller device 20 disposed upstream thereof. The registration roller device 10 and the pre-registration roller device 20 have drive rollers 11 and 21 at the bottom and pinch rollers 15 and 25 at the top, respectively, with the paper path in between, and the roller devices convey the paper in a nipped state. configured to do so.

Further, the gate member 6 disposed close to the registration roller device 10 is conveyed in the paper path with the gate claw member 7 disposed at the tip thereof protruding into the paper path. This will stop the paper that is coming. In the paper alignment device of the present invention, the gate member 6 temporarily stops the paper, and in this state, the takeaway roller 20a continues to feed the paper, so that the leading end is locked by the gate claw. The paper is caused to perform an action to form a loop. Note that when the take-away roller 20a is performing the feeding action, the nip of the pre-registration roller 20 is released. After lowering the gate member 6 at a predetermined timing, the leading edge of the paper enters the nip portion of the registration roller device 10, and the registration roller device 10 is moved in the width direction of the paper to remove the paper. Performs position alignment. In the paper alignment device 1 of the present invention, each pinch roller 15, 25 is supported by a member that can move toward and away from the drive roller, and furthermore, the upper and lower rollers 11, 15 of the registration roller device 10 are It is provided so that it can move in the axial direction (width direction of the paper path).

In the sheet aligning device 1 shown in FIG. 1, the lower members including the drive rollers 11 and 21 are constructed as shown in FIG. In the example shown in FIG. 2, the lower frame 2 includes the drive roller 11 of the registration roller device and the drive roller 21 of the pre-registration roller device.
are arranged, and each roller is constituted by a roller member provided in a skewered manner at a predetermined interval on the drive shafts 12 and 22, respectively. Furthermore, input gears 13 and 23 are arranged for each shaft, and each input gear meshes with a transmission gear 14 and the like to transmit driving force. A paper detection sensor 8 is disposed at a position corresponding to a reference line H for conveying the paper with respect to the paper path constituted by the roller device. The position of the incoming paper is detected, and based on the information, each device of the register alignment device 30 is operated to perform the paper alignment action.

Drive roller 11 of the registration roller device 10
An engaging member 31 for the pinch roller is provided at one end of the shaft 12, and as described later, when the pinch roller is combined with the drive roller 11, the engaging member 31 provided on the shaft of the drive roller is For the concave grooved roller 33 of 31,
The rollers with protrusions in the shape of beads provided on the shaft of the pinch roller mesh with each other, and the upper and lower rollers are positioned in correspondence with each other.

In addition to the input gear 13 as described above, a registration device 30 for moving the shaft 12 and positioning the shaft 12 is disposed at the other end of the shaft 12 of the drive roller. ing. The registration device 30 includes a motor 40, a pinion 41, and a rack member 42.
In addition to a member for moving the shaft 12 in the axial direction, the registration roller device 10 is positioned by an actuator 45 and a sensor 46. In addition,
The detection mechanism including the actuator 45 and the sensor 46 is used to position the drive roller 11. After moving the shaft 12 and performing an alignment action on the paper, the sensor 46 detects the drive roller 11. It is returned to the set home position so that the next alignment action can be performed.

In the registration roller device 10, an input gear 23 is arranged at one end of the shaft 22 of the drive roller 21 of the pre-registration roller device 20 disposed upstream in the paper conveyance direction, and the input gear 23 is arranged at one end of the shaft 22 to drive the shaft. However, the axis 22
An arm operating member 72 is arranged at the other end. As will be explained in detail later, by operating the arm operating member 72, the pinch roller is separated from the drive roller when the paper nip is released in the pre-registration roller device. .

(Configuration of upper member of paper aligning device) In the present invention, the lower member shown in FIG.
A pinch roller assay 50 such as that shown in FIG. 3 is used, with a pinch roller positioned for each drive roller so that a paper nip action can be performed between each roller. In the example shown in FIG. 3, the upper frame 51 is arranged relative to the main body frame 2 shown in FIG. The shaft of the pinch roller 25 is vertically supported in a shaft support hole 54 provided in the frame. Further, a torsion spring member 60 is attached to the upper frame 51 via a support shaft 55.
and a bracket 65, and the arm member protruding from the front and rear of the torsion spring member 60 is connected to the bracket 65.
to provide more support.

The torsion spring member 60 includes:
As shown in FIG. 5, an arm member 61 that protrudes back and forth
, 62 are arranged, and at the tips of the arm members 61 and 62,
Pressing members 63 and 64 are provided. the pressing member 63;
Reference numeral 64 acts to press the shafts of the pinch rollers 15 and 25 from above, and allows the shaft 16 of the pinch roller 15 to slide in the axial direction even when pressed by the pressing member. ing. The bracket 65 disposed with respect to the torsion spring member 60 is supported so as to be swingable with respect to the support shaft 55.
It functions to prevent the torsion spring member 60 from swinging significantly.

In the pinch roller assay 50 configured as described above, when the upper frame 51 is attached to the main body frame, as shown in FIG. Members 63, 6
4 is placed at a position with some margin, and the shaft is not pressed by the pressing member. On the other hand, the upper frame 51 is fixed by a fixing means (not shown).
When the body frame is positioned, as shown in FIG. 4, the shaft 26 of the pinch roller 25 is engaged with the swinging arm member 70 held at a fixed position, and is pushed up by the swinging arm member 70. It becomes a state where Then, the pressing member 64 is pressed against the upper portion of the shaft 26, and the driving roller 21 located below the pinch roller 25 and the pinch roller 25 come into contact with each other with a predetermined pressing force. The swing arm member 70 is used to release the paper nip in the pre-registration roller device, as will be explained later with reference to FIG.

As mentioned above, the pre-registration roller device 20
When the nip state is set, one arm member 52 of the torsion spring member 60 is pushed up by the shaft 26, and as a reaction, the other arm member 61 swings counterclockwise via the support shaft 55. be moved. Therefore, the pressing member 63 disposed at the tip of the arm 61 comes into a state of pressing the shaft 16 of the pinch roller 15, and a nip state is set between the upper and lower rollers in the registration roller device 10. Then, as shown in FIG. 4, with each roller device of the sheet aligning device 1 positioned, the sheet is conveyed and positioned.

(Alignment mechanism for upper and lower rollers in registration roller device) When setting up the paper alignment device 1 as shown in FIG. 1 by combining the devices shown in FIGS. uses an engaging member 31 as shown in FIG. Engagement member 3 shown in FIG. 6
1, a roller 32 with protrusions in the shape of a bead is arranged on the shaft 16 of the pinch roller 15, and the drive roller 11
A grooved roller 33 provided with a groove is disposed on the shaft 12 of the roller. When closing the upper frame of the main body, which is opened like an alligator, to the lower frame, the pinch roller 15 supported by the upper frame is accurately positioned with respect to the drive roller 11 supported by the main body frame. cause the action to take place.

When positioning the upper and lower roller members, the central protrusion of the protruding roller 32 is aligned with the concave grooved roller 3.
3, the protruding roller 32 is mounted while moving the shaft 16 while sliding along the slope of the groove of the concave grooved roller 33, and the upper and lower rollers are A positioning action is performed. Further, as described above, when the pinch roller 15 is engaged with the drive roller 11, the pressing member shown in FIGS. 3 to 5 applies a pressing action to the axis of the pinch roller 15. Therefore, the shaft 16 of the pinch roller is easily moved in the axial direction by the engagement of the protruding roller 32 and the grooved roller 33.

Then, with the upper and lower rollers positioned, the registration device 30 shown in FIG. 2 is driven.
When aligning the sheets, the registration roller device is moved in the axial direction via the engagement member 31 that positions the upper and lower rollers, and the sheet nipped by the registration roller device is moved in the width direction. conduct. That is, the engaging member 31 of the present invention is used not only as a means for positioning the upper and lower rollers, but also as an interlocking means when moving the paper in the lateral direction.

As described above, in addition to providing the roller positioning means on the engaging member 31, in the present invention,
A mechanism as shown in FIG. 7 can be used as an interlocking means for the upper and lower rollers. Note that the engaging member shown in FIG. 7 is used when the upper and lower roller devices are moved laterally in an interlocked state by separately providing means for positioning the pinch roller with respect to the drive roller. In the engagement member shown in FIG. 7, a grooved pulley 35 is disposed on the shaft of the drive roller 11, and a disc member 36 is disposed on the shaft 16 of the pinch roller 15. Then, as in the case of FIG. 6, with the disc member 36 engaged with the groove of the grooved pulley 35, the upper and lower roller members are interlocked in the axial direction to perform an alignment action on the paper. Let them do it.

(Nip release mechanism in pre-registration roller device) As shown in FIGS. 2 and 3, the pre-registration roller device 20 of the present invention includes a swinging arm member 70 that engages with the lower part of the shaft 26 of the pinch roller 25. It is placed. As shown in FIG. 2, the swing arm member 70 is supported on both sides of the main body frame 2 via a support shaft 71, and swings about the shaft 71 when the cam member 75 is rotated. It is set up so that Further, the cam member 75 is supported by a drive shaft 73, and an arm operating member 72 is provided between the shaft 73 and the shaft 22 of the drive roller 21.

When aligning the sheets using the registration roller device 10, a state is set in which the paper nip in the pre-registration roller device 20 is released and horizontal movement of the sheet is allowed. At this time, the arm actuating member 72 shown in FIG. Raise the shaft 26. Therefore, by separating the roller 25 from the drive roller 21, the nip caused by the pre-registration roller device is released for the paper whose leading end is nipped by the registration roller device, and the movement of the paper to be aligned is released. Failures will be prevented from occurring. In this case, the trailing edge of the paper is in a state where it is nipped by the takeaway roller 20a. The take-away roller 20a is preferably placed as far away from the registration roller 10 as possible in order to facilitate the movement of the paper in the registration roller device 10, but the distance between the two is not limited to that used in a copying machine. The trailing edge of the smallest size paper is set at the nipping position.

As described above, the cam member 75 for swinging the arm member has a cam as shown in FIG. A surface 76 is formed. In the illustrated example, the cam surface 76 is formed with two surfaces,
Even if the cam member 75 is driven and the cam stop position varies, the swing arm member 70 can be held at the raised position. In other words, even if the sensor for controlling the arm actuating member 75 for the swinging arm member 70, the clutch mechanism, etc. do not operate accurately, and variations occur in the operation of these members, the cam member 75 When one of the plurality of cam surfaces provided on the cam surface acts accurately on the swing arm member 70, the paper nip in the pre-registration roller device can be released.

[0029] Then, the state as shown in FIG.
Alternatively, as shown in FIG. 9, even if the other cam surface pushes up the swing arm member 70, the swing arm member 70
acts to push up the shaft 26 of the pinch roller, separating the pinch roller 25 from the drive roller 21, and releasing the paper nip in the pre-registration roller device. Therefore, as described above, by using the cam member 75 having a plurality of cam surfaces, for example, when the clutch of the arm actuating member 72 is actuated to stop the drive shaft 73, the timing of the stop may be slightly affected. Even if misalignment occurs, it is possible to accurately release the nip state in the pre-registration roller device.

(Paper alignment action) In the paper alignment device of the present invention constructed as described above, when performing paper alignment action using the registration roller device, first, the claw 7 of the gate member 6 is aligned with the paper path. The claw member 7 protrudes to block the leading edge of the paper being conveyed. In this state, the nip by the pre-registration roller device 20 is released, and the upstream takeaway roller 20a applies a feeding force to the paper, thereby forming a loop on the paper. Next, when the gate is opened with the paper nipped by the takeaway roller 20a, the leading edge of the paper protrudes into the registration roller device 10 and is nipped between the drive roller 11 and the pinch roller 15. In this state, the paper sensor 8 provided in the paper path detects the position of the side of the paper and outputs a drive signal to the registration device 30.

When aligning the sheets based on the signal from the sheet sensor 8, the leading end of the sheet is nipped by the registration roller device 10, and the nip by the pre-registration roller device 20 is released, as shown in FIG. In this way, means is used to align the paper P with respect to the sensor 8 while moving it in the position direction. In other words, when the side of the paper P is blocking the sensor 8 as shown in Figure A, the registration roller device is used to move the paper P to the right side as shown in At the position where the side portion is detected by the sensor 8, the alignment action is completed.

Furthermore, as shown in FIG. 10C,
If the paper is located inside the sensor, move the paper excessively so that it first passes the position where it is detected by the sensor, and move it to the position shown in Figure D. Stop at. Next, the paper is moved to the position shown in FIG. 8E, and when the side of the paper is detected by the sensor 8, the alignment action is completed. Then, after performing the paper alignment action as described above, the push-up action on the pinch roller of the pre-registration roller device is released, the nip state of the paper in the pre-registration roller device is set, and the registration roller device and the pre-registration roller device are The paper is sent out toward the image transfer section.

In the present invention, when the paper is aligned in the manner described above, the position of the roller in the registration roller device will deviate from the original position of the roller. Therefore, the actuator 45 provided on the pinch roller of the registration roller device is returned to the position where it can be detected by the sensor 46, and the drive roller 1
It is necessary to perform an operation to set the first home position. However, when the image forming apparatus is used continuously, there is no need to return the rollers of the registration roller device to the home position, so a means for initializing the image forming apparatus is provided when the image forming apparatus is started up. Make sure to use it. Furthermore, when performing the initializing action as described above, if an action is performed to drive the shaft of the roller in the axial direction while rotating the drive shaft 12,
Even if the shaft is pressed by the pressing member 63, the pinch roller 15 can be easily moved in the axial direction.

[0034] If the rollers of the registration roller device remain in a shifted state when performing work such as jam removal, the positioning of the pinch rollers with respect to the drive rollers will be hindered. When opening, it is necessary to configure the device to perform the initializing operation, and a program for the operation is set in the control device of the image forming apparatus. Therefore, as described above, by causing the drive roller 11 to perform the initializing operation, it is possible to easily align the upper and lower rollers when closing the alligator mouth.

[0035]

Effects of the Invention Since the paper aligning device of the present invention is configured as described above, it is possible to accurately align the paper at the portion immediately before the image transfer section, so that the image transferred to the paper can be adjusted accurately. It is possible to prevent discrepancies from occurring and obtain copies in good condition. Furthermore, by providing the registration roller device of the present invention with an alignment mechanism for the upper and lower rollers, when the upper frame opened in the shape of an alligator mouth is closed, the function of positioning the upper and lower rollers can be performed accurately. The upper and lower rollers of the registration roller device can be moved laterally in conjunction with each other. Furthermore, when registering the sheets in a state where they are nipped by the registration roller device, the nip caused by the pre-registration roller device can be released, so that the sheets can be aligned in a good condition.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the configuration of a paper alignment device of the present invention.

FIG. 2 is a plan view showing the configuration of a lower member of the paper alignment device.

FIG. 3 is a side view showing the configuration of the upper member.

FIG. 4 is an explanatory diagram of a state in which the pinch roller supported by the upper member is positioned on the drive roller.

FIG. 5 is a plan view of the pressing member support mechanism of the present invention.

FIG. 6 is a front view showing the configuration of engagement members of upper and lower rollers in the registration roller device.

FIG. 7 is a front view of another embodiment of the engagement member.

FIG. 8 is an explanatory diagram of the operation of a nip release member in the pre-registration roller device.

9 is an explanatory diagram of the operation of the swinging arm member corresponding to FIG. 8 when the cam member rotates extra; FIG.

FIG. 10 is an explanatory diagram showing the operation of paper alignment in the paper alignment device of the present invention.

[Symbols in the diagram] 1 Paper aligning device 6 Gate device 8 Paper sensor 10 Registration roller device 20 Pre-registration roller device 30 Registration alignment device 32 Roller with protrusions 33 Roller with grooves 46 Sensor 50 Pinch roller assay 60 Torsion spring members 63 and 64
Pressing member 70 Swing arm member

Claims (3)

[Claims] 1. An upper frame on which an image forming member such as a photoreceptor is disposed is provided so as to be openable and closable in an alligator shape with a paper conveyance path as a boundary with respect to a lower frame on which a paper feeding member is mounted, and A means for positioning the leading edge of the paper is disposed immediately before the image transfer section from the photoreceptor, and the paper is temporarily stopped by the paper positioning means to transfer the image in accordance with the image formed on the photoreceptor. In an apparatus configured to feed paper, the paper temporary stop means includes a gate member, a registration roller device disposed downstream of the gate member, and
A pre-registration roller device disposed upstream of the gate, and a paper position detection member disposed at a position corresponding to the paper conveyance reference line of the paper path, and a drive roller and a disposing means for mutually positioning the pinch rollers, nipping the paper between the upper and lower roller members, and providing means for moving the paper in the lateral direction with the paper sandwiched between the upper and lower rollers; A paper position correction device characterized in that the paper is moved laterally in accordance with a signal from the paper position detection member. 2. The pinch roller of the registration roller device is provided with means for applying a pressing force to the drive roller,
The pressing means is provided with a member capable of sliding in the axial direction of the shaft of the pinch roller, and the pressing force applying means applies a pressing action only when the pinch roller is positioned with respect to the drive roller. The paper position correction device according to claim 1, characterized in that the paper position correction device is configured so as to be able to perform the following functions. 3. A pre-registration roller device disposed upstream of the registration roller device is provided with a means for releasing the nip on the paper, and when the registration roller device aligns the paper, the nip of the paper in the pre-registration roller device is released. The paper position correction device according to claim 1, characterized in that: