JP2011144048A - Conveying device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conveying device and image forming apparatus capable of correcting displacement of a recording medium to be conveyed toward an image transfer unit with high accuracy. <P>SOLUTION: The conveying device includes a first longitudinal resist corrector 32 for correcting the displacement in the conveying direction of the recording medium, a transverse resist corrector 31 for correcting the displacement in the width direction of the recording medium after correcting the displacement in the conveying direction by the first longitudinal resist corrector 32, and a second longitudinal resist corrector 33 for correcting the displacement in the conveying direction of the recording medium again after correcting the displacement in the width direction by the transverse resist corrector 31. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a conveyance device that conveys a recording medium toward an image transfer unit, and an image forming apparatus using an electrophotographic method such as a copying machine, a printer, a facsimile, or a composite machine including the same. It is.

  Conventionally, in an image forming apparatus such as a copying machine or a printer, an image carried on an image carrier such as a photosensitive drum or an intermediate transfer belt is accurately transferred to a desired position on a recording medium by an image transfer unit. In order to transfer, a technique is known in which a recording medium is conveyed to an image transfer unit with registration rollers in a timely manner (see, for example, Patent Document 1 and Patent Document 2). The “positional deviation” refers to a deviation from a regular image transfer position.

In Patent Document 1 and the like, after a recording medium is abutted against an abutting member (gate device) and the leading end of the recording medium is positioned, the recording medium is loaded by a registration roller device disposed on the downstream side of the abutting member. The registration roller device is moved in the width direction in the sandwiched state to correct the positional deviation in the width direction of the recording medium (the direction perpendicular to the conveying direction), and then the recording medium is directed toward the image transfer section. Techniques for conveying are disclosed.
Further, in Patent Document 2, etc., after a recording medium is abutted against an abutting member (abutting surface) to correct the skew of the recording medium, an image is formed by a pair of registration rollers disposed on the upstream side of the abutting member. A technique for conveying a recording medium toward a transfer unit is disclosed.

In the conventional technique described above, the positional deviation of the recording medium conveyed toward the image transfer unit is not sufficiently corrected, and the image may not be accurately transferred to a desired position on the recording medium.
Specifically, in the techniques of Patent Document 1, Patent Document 2, and the like, after the recording medium is abutted against the abutting member, the recording medium is held between the roller pair disposed on the upstream side of the abutting member. Become. At this time, the leading end of the recording medium that is abutting against the abutting member is displaced due to a difference in rigidity of the recording medium, and the position in the transport direction (hereinafter, referred to as “vertical resist” as appropriate) is shifted. Deviation of the image transfer start position with respect to the recording medium conveyed to the transfer unit occurs.
Further, the technique of Patent Document 1 and the like is based on the position in the width direction of the recording medium (hereinafter referred to as “lateral registration” as appropriate) in a state where the recording medium is held by a registration roller device disposed on the downstream side of the abutting member. In some cases, the vertical registration of the recording medium may be misaligned.
Such a problem cannot be ignored particularly in a high-speed image forming apparatus in which the recording medium is conveyed at a high speed, because the vertical registration and the horizontal registration of the recording medium are liable to shift or skew.

  The present invention has been made to solve the above-described problems, and provides a conveyance device and an image forming apparatus in which a positional deviation of a recording medium conveyed toward an image transfer unit is accurately corrected. It is in.

  According to a first aspect of the present invention, there is provided a transport apparatus for transporting a recording medium toward an image transfer unit that transfers an image carried on the image carrier onto the recording medium. A first vertical registration correction unit that corrects a positional deviation in the conveyance direction of the medium; and a horizontal registration that corrects a positional deviation in the width direction of the recording medium after the positional deviation in the conveyance direction is corrected by the first vertical registration correction unit. And a second vertical registration correction unit that corrects again the positional deviation in the conveyance direction of the recording medium after the positional deviation in the width direction is corrected by the lateral registration correction unit.

  According to a second aspect of the present invention, there is provided the conveying device according to the first aspect, wherein the first vertical registration correcting means is an abutting member that abuts the leading end of the recording medium, and conveys the recording medium. The route can be opened and closed.

  According to a third aspect of the present invention, in the transport device according to the second aspect, the lateral registration correcting means moves in the width direction after sandwiching the recording medium that is in contact with the abutting member. A sandwiching roller configured to be capable of being disposed upstream of the abutting member in the recording medium conveyance direction.

  According to a fourth aspect of the present invention, in the conveying apparatus according to the third aspect, the second vertical registration correcting means is disposed downstream of the abutting member in the conveying direction of the recording medium. The registration roller is configured to convey the recording medium toward the registration roller by the sandwiching roller in a state where the conveyance path is opened by the abutting member, and to perform positional deviation correction in the width direction. .

  According to a fifth aspect of the present invention, there is provided the conveying device according to the fourth aspect, wherein when the recording medium is conveyed to the image transfer section by the registration roller, the holding of the recording medium by the holding roller is released. To do.

  According to a sixth aspect of the present invention, there is provided a conveyance device according to the fourth or fifth aspect, wherein the displacement in the width direction of the recording medium is detected between the sandwiching roller and the registration roller. The nipping roller includes a detecting unit, and corrects the displacement in the width direction of the recording medium based on the detection result of the detecting unit.

  According to a seventh aspect of the present invention, in the conveying apparatus according to any of the fourth to sixth aspects, the registration roller can vary the speed at which the recording medium is conveyed.

  According to an eighth aspect of the present invention, there is provided the transport apparatus according to any one of the first to seventh aspects, wherein the first vertical registration correction unit and the second vertical registration correction unit are a recording medium. Is also corrected.

  An image forming apparatus according to a ninth aspect of the present invention includes the conveyance device according to any one of the first to eighth aspects.

  In the present invention, since the first vertical registration correction unit, the horizontal registration correction unit, and the second vertical registration correction unit are installed, the positional deviation of the recording medium conveyed toward the image transfer unit is accurately corrected. A conveying device and an image forming apparatus can be provided.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. It is sectional drawing which shows an image formation part. It is the schematic which shows a conveying apparatus and its vicinity. It is the top view which looked at the conveying apparatus in the width direction. It is the schematic which shows operation | movement of a conveying apparatus. FIG. 6 is a schematic diagram illustrating the operation of the conveyance device following FIG. 5.

Embodiment.
Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In addition, in each figure, the same code | symbol is attached | subjected to the part which is the same or it corresponds, The duplication description is simplified or abbreviate | omitted suitably.

First, the configuration and operation of the entire image forming apparatus will be described with reference to FIGS.
FIG. 1 is a block diagram showing a printer as an image forming apparatus, and FIG. 2 is an enlarged view showing an image forming unit thereof.
As shown in FIG. 1, an intermediate transfer belt device 15 is installed in the center of the image forming apparatus main body 100. Further, image forming units 6Y, 6M, 6C, and 6K corresponding to the respective colors (yellow, magenta, cyan, and black) are arranged in parallel so as to face the intermediate transfer belt 8 of the intermediate transfer belt device 15. The conveying device 30 is disposed on the lower right side of the intermediate transfer belt device 15.

  Referring to FIG. 2, an image forming unit 6Y corresponding to yellow includes a photosensitive drum 1Y serving as an image carrier, a charging unit 4Y disposed around the photosensitive drum 21, a developing unit 5Y, and a cleaning unit 2Y. , And a static elimination unit (not shown). Then, an image forming process (charging process, exposure process, developing process, transfer process, cleaning process) is performed on the photosensitive drum 1Y, and a yellow image is formed on the photosensitive drum 1Y.

  The other three image forming units 6M, 6C, and 6K have substantially the same configuration as that of the image forming unit 6Y corresponding to yellow except that the color of the toner used is different. A corresponding image is formed. Hereinafter, description of the other three image forming units 6M, 6C, and 6K will be omitted as appropriate, and only the image forming unit 6Y corresponding to yellow will be described.

Referring to FIG. 2, the photosensitive drum 1Y is driven to rotate counterclockwise in FIG. 2 by a drive motor (not shown). Then, the surface of the photosensitive drum 1Y is uniformly charged at the position of the charging unit 4Y (a charging process).
Thereafter, the surface of the photosensitive drum 1Y reaches the irradiation position of the laser beam L emitted from the exposure unit 7, and an electrostatic latent image corresponding to yellow is formed by exposure scanning at this position (in the exposure process). is there.).

Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the developing portion 5Y, and the electrostatic latent image is developed at this position to form a yellow toner image (image) (development process). ).
Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the intermediate transfer belt 8 and the transfer roller 9Y, and the toner image on the photosensitive drum 1Y is transferred onto the intermediate transfer belt 8 at this position (primary). It is a transfer process.) At this time, a small amount of untransferred toner remains on the photosensitive drum 1Y.

Thereafter, the surface of the photosensitive drum 1Y reaches a position facing the cleaning unit 2Y, and untransferred toner remaining on the photosensitive drum 1Y at this position is collected in the cleaning unit 2Y by the cleaning blade 2a (cleaning). Process.)
Finally, the surface of the photosensitive drum 1Y reaches a position facing a neutralization unit (not shown), and the residual potential on the photosensitive drum 1 is removed at this position.
Thus, a series of image forming processes performed on the photosensitive drum 1Y is completed.

The image forming process described above is performed in the other image forming units 6M, 6C, and 6K in the same manner as the yellow image forming unit 6Y. That is, a laser beam L based on image information is irradiated from the exposure unit 7 disposed above the image forming unit onto the photosensitive drums 1M, 1C, and 1K of the image forming units 6M, 6C, and 6K. Is done. Specifically, the exposure unit 7 emits a laser beam L from a light source, and irradiates the photosensitive drum through a plurality of optical elements while scanning the laser beam L with a polygon mirror that is rotationally driven.
Thereafter, the toner images of the respective colors formed on the respective photosensitive drums through the development process are transferred onto the intermediate transfer belt 8 serving as an image carrier. In this way, a color image is formed on the intermediate transfer belt 8.

  Here, referring to FIG. 3, the intermediate transfer belt device 15 includes an intermediate transfer belt 8, four transfer rollers 9Y, 9M, 9C and 9K, a driving roller 12A, a counter roller 12B, tension rollers 12C to 12F, an intermediate transfer. The cleaning unit 10 is configured. The intermediate transfer belt 8 is stretched and supported by a plurality of roller members 12A to 12F, and is endlessly moved in the direction of the arrow in FIG. 3 by the rotational drive of one roller member (drive roller) 12A.

The four transfer rollers 9Y, 9M, 9C, and 9K sandwich the intermediate transfer belt 8 between the photosensitive drums 1Y, 1M, 1C, and 1K to form a primary transfer nip. Then, a transfer voltage (transfer bias) opposite to the polarity of the toner is applied to the transfer rollers 9Y, 9M, 9C, and 9K.
The intermediate transfer belt 8 (image carrier) travels in the direction of the arrow and sequentially passes through the primary transfer nips of the transfer rollers 9Y, 9M, 9C, and 9K. In this way, the toner images of the respective colors on the photosensitive drums 1Y, 1M, 1C, and 1K are primarily transferred while being superimposed on the intermediate transfer belt 8.

  Thereafter, the intermediate transfer belt 8 onto which the toner images of the respective colors are transferred in a superimposed manner reaches a position facing the secondary transfer roller 19 (image transfer portion). At this position, the counter roller 12B sandwiches the intermediate transfer belt 8 with the secondary transfer roller 19 to form a secondary transfer nip (image transfer portion). The four-color toner images formed on the intermediate transfer belt 8 are transferred onto a recording medium P such as transfer paper conveyed to the position of the secondary transfer nip. At this time, untransferred toner that has not been transferred to the recording medium P remains on the intermediate transfer belt 8.

Thereafter, the intermediate transfer belt 8 reaches the position of the intermediate transfer cleaning unit 10. At this position, the untransferred toner on the intermediate transfer belt 8 is removed.
Thus, a series of transfer processes performed on the intermediate transfer belt 8 is completed.

Here, referring to FIG. 1, the recording medium P transported to the position of the secondary transfer nip is fed to the paper feeding unit 26 (or laterally fed) disposed below the apparatus main body 100. From the paper section) via the paper feed roller 27, the transport device 30 and the like.
Specifically, a plurality of recording media P such as transfer paper are stored in the paper supply unit 26 in a stacked manner. When the paper feed roller 27 is driven to rotate counterclockwise in FIG. 1, the uppermost recording medium P is fed toward the transport device 30.

  The recording medium P transported to the position of the transport apparatus 30 is subjected to vertical registration correction (position shift correction in the transport direction), horizontal registration correction (position shift correction in the width direction), and skew correction (skew correction) by the transport apparatus 30. After that, it is conveyed toward the secondary transfer nip (image transfer portion) in time with the color image on the intermediate transfer belt 8. In this way, a desired color image is transferred onto the recording medium P. The configuration and operation of the transfer device 30 will be described in more detail later with reference to FIGS.

Thereafter, the recording medium P on which the color image is transferred at the position of the secondary transfer nip is conveyed to the position of the fixing unit 20. At this position, the color image transferred on the surface is fixed on the recording medium P by heat and pressure generated by the fixing roller and the pressure roller.
Thereafter, the recording medium P is discharged out of the apparatus by a pair of discharge rollers (not shown). The transferred P discharged from the apparatus by the pair of paper discharge rollers is sequentially stacked on the stack unit as an output image.
Thus, a series of image forming processes in the image forming apparatus is completed. Note that the process linear velocity (the traveling speed of the intermediate transfer belt 8 and the conveyance speed of the recording medium P) of the image forming apparatus in the present embodiment is set to about 400 mm / second.

Next, the configuration and operation of the developing unit in the image forming unit will be described in more detail with reference to FIG.
The developing unit 5Y includes a developing roller 51Y that faces the photosensitive drum 1Y, a doctor blade 52Y that faces the developing roller 51Y, two transport screws 55Y disposed in the developer containing unit, and an opening in the developer containing unit. A toner replenishment path 43Y that communicates with each other via a toner density, a density detection sensor 56Y that detects a toner density in the developer, and the like. The developing roller 51Y includes a magnet fixed inside, a sleeve rotating around the magnet, and the like. In the developer accommodating portion, a two-component developer composed of a carrier and toner is accommodated.

The developing unit 5Y configured as described above operates as follows.
The sleeve of the developing roller 51Y rotates in the direction of the arrow in FIG. The developer carried on the developing roller 51Y by the magnetic field formed by the magnet moves on the developing roller 51Y as the sleeve rotates. Here, the developer in the developing device 5Y is adjusted so that the toner ratio (toner concentration) in the developer is within a predetermined range.
Thereafter, the toner replenished in the developer accommodating portion circulates through the two separated developer accommodating portions while being mixed and stirred together with the developer by the two conveying screws 55Y (movement in the direction perpendicular to the paper surface of FIG. 2). .) The toner in the developer is attracted to the carrier by frictional charging with the carrier, and is carried on the developing roller 51Y together with the carrier by the magnetic force formed on the developing roller 51Y.

  The developer carried on the developing roller 51Y is conveyed in the direction of the arrow in FIG. 2 and reaches the position of the doctor blade 52Y. The developer on the developing roller 51Y is conveyed to a position facing the photosensitive drum 1Y (development area) after the developer amount is made appropriate at this position. The toner is attracted to the latent image formed on the photosensitive drum 1Y by the electric field formed in the development area. Thereafter, the developer remaining on the developing roller 51Y reaches the upper portion of the developer accommodating portion as the sleeve rotates, and is detached from the developing roller 51Y at this position.

Next, with reference to FIGS. 3 to 6, the conveyance device 30 that is characteristic in the present embodiment will be described in detail.
3 and 4, the conveyance device 30 includes a conveyance roller 28 and a nipping roller 31 serving as a lateral registration correction unit along a conveyance path of the recording medium (a path indicated by a broken line in FIG. 3). In addition, an abutting member 32 as a first vertical registration correction unit and a registration roller 33 as a second vertical registration correction unit are provided. Further, a CIS 37 (contact image sensor) as a detecting means is disposed between the abutting member 32 and the registration roller 33. Further, a photo sensor 38 is disposed between the registration roller 33 and the secondary transfer nip (image transfer portion).

  Here, the abutting member 32 as the first vertical registration correcting means is a metal plate having an abutting surface (divided into a plurality of parts in the width direction) against which the leading end of the recording medium P abuts. The leading edge of the recording medium P abuts against the abutting member 32, and the vertical registration of the recording medium P is corrected. Further, the skew of the recording medium P is also corrected by the end of the recording medium P abutting against the abutting member 32. The abutting member 32 is configured to open and close the conveyance path of the recording medium P. Specifically, by driving a cam mechanism (not shown) that engages the abutting member 32, the abutting member 32 moves upward in FIG. 3 is moved downward to open the conveyance path.

  The sandwiching roller 31 as the lateral registration correcting means is a roller pair having a plurality of roller portions divided in the width direction, and is disposed upstream of the abutting member 32 in the conveyance direction of the recording medium P. The sandwiching roller 31 is configured to be able to contact and disengage the roller pair by a driving mechanism (not shown) and to be movable in the width direction (in the direction of the broken line arrow S in FIG. 4). ing. Then, the lateral registration of the recording medium P is corrected by moving in the width direction after the recording medium P in a state where the clamping roller 31 is in contact with the abutting member 32.

  The registration rollers 33 as the second vertical registration correction means are a pair of rollers disposed on the downstream side in the conveyance direction of the recording medium P with respect to the abutting member 32. Then, the recording medium P after the lateral registration is corrected by the sandwiching roller 31 hits the nip portion of the registration roller 33, and the vertical registration of the recording medium P is corrected again. In addition, the skew of the recording medium P is also corrected when the leading edge of the recording medium P hits the registration roller 33.

  The CIS 37 serving as a detection means includes a plurality of photosensors (consisting of a light emitting element such as an LED and a light receiving element such as a photodiode) arranged in the width direction. By detecting the position, the shift amount of the lateral resist is detected. Then, based on the detection result of the CIS 37, the lateral registration correction by the sandwiching roller 31 is performed.

  The photo sensor 38 is disposed downstream of the registration roller 33 in the conveyance direction of the recording medium P, and optically detects the tip of the recording medium P conveyed from the registration roller 33. Then, based on the detection result of the photo sensor 38, the conveyance timing of the recording medium P conveyed toward the secondary transfer nip by the registration roller 33 is finely adjusted.

Hereinafter, the operation of the transport device 30 configured as described above will be described in detail with reference to FIGS. 5 (A) to 5 (D) and FIGS. 6 (A) to 6 (D).
First, as shown in FIG. 5A, the recording medium P fed from the paper feeding unit 26 is conveyed toward the position of the abutting member 32 by the rotation of the conveying roller 28 in the R1 direction (broken line). It is the conveyance in the direction of the arrow.) At this time, the clamping roller 31 is moving in a direction (A1 direction) that opens the conveyance path. Further, the abutting member 32 moves in a direction (B1 direction) for closing the conveyance path.

Thereafter, as shown in FIG. 5B, the recording medium P stops when the leading end of the recording medium P abuts against the abutting member 32. Then, as shown in FIG. 5C, the rotation of the conveying roller 28 is stopped, and the clamping roller 31 moves in the direction in which the recording medium P is clamped (direction A2). At this time, a part of the recording medium P is bent.
Then, the vertical registration of the recording medium P is corrected. That is, after that, the nipping roller 31 is rotated in synchronization with the color image on the intermediate transfer belt 8, and the recording medium P is conveyed toward the registration roller 33.
Further, the skew of the recording medium P is also corrected by the abutting of the leading end of the recording medium P against the abutting member 32. That is, even if the recording medium P is transported in an oblique posture with respect to the transport direction (skewed), one end of the leading end first strikes against the abutting member 32 and eventually the other end also becomes the center. Abutting against the abutting member 32, the skew of the recording medium P is finally corrected.

Thereafter, as shown in FIG. 5D, the conveyance roller 28 moves in the direction (C1 direction) that opens the conveyance path, and the abutting member 32 also opens the conveyance path (direction B2). .) That is, the recording medium P is sandwiched only by the sandwiching roller 31.
At this time, the leading end of the recording medium P that is in contact with the abutting member 32 may be displaced due to a difference in rigidity of the recording medium P or the like. In such a case, the corrected vertical resist is displaced by abutting against the abutting member 32. Such vertical resist misalignment is likely to occur particularly when a thin recording medium P (thin paper) is used.

Thereafter, as shown in FIG. 6A, the recording medium P is conveyed toward the position of the registration roller 33 by the rotation of the sandwiching roller 31 in the R2 direction (conveyance in the direction of the broken line arrow). At this time, the displacement amount of the lateral registration of the recording medium P is detected by the CIS 37, and the clamping roller 31 moves in the direction perpendicular to the paper surface (S direction) so as to cancel the displacement amount. For example, in FIG. 4, when the lateral registration of the recording medium P is shifted by 3 mm to the right, the clamping roller 31 that clamps the recording medium P is shifted by 3 mm to the left.
In this way, the recording medium P is conveyed toward the registration roller 33 by the pinching roller 31 in a state where the conveyance path is opened by the abutting member 32, and lateral registration correction is performed.

Thereafter, as shown in FIG. 6B, the front end of the recording medium P whose lateral registration has been corrected hits the registration roller 33 and stops. At this time, the conveyance roller 28 moves in the direction (C2 direction) in which the recording medium P is conveyed in preparation for the conveyance of the next recording medium.
Then, as shown in FIG. 6C, the rotation of the conveying roller 28 is resumed, and the clamping roller 31 moves in a direction in which the recording medium P is released (A1 direction). Further, when the registration roller 33 rotates and the front end of the recording medium P is detected by the photo sensor 38, the rotation of the registration roller 33 is temporarily stopped.

Then, the vertical registration of the recording medium P is corrected. That is, thereafter, as shown in FIG. 6D, the recording medium P is conveyed toward the secondary transfer nip in synchronization with the color image on the intermediate transfer belt 8. Thus, the color image is transferred to a desired position on the recording medium P.
Note that the registration roller 33 is configured such that its rotation speed can be varied by driving by a variable drive motor (not shown). Accordingly, since the conveyance speed of the recording medium P conveyed from the registration roller 33 toward the secondary transfer nip can be adjusted, the vertical registration can be adjusted with higher accuracy.

At this time, the abutting member 32 moves in a direction (B1 direction) for closing the conveyance path, and preparation for vertical registration correction is performed on the next recording medium P ′ conveyed by the conveyance roller 28. .
In FIG. 6B, the skew of the recording medium P is also corrected when the leading edge of the recording medium P hits the nip portion of the registration roller 33. That is, even if the recording medium P is skewed, one end of the leading end first hits the nip portion of the registration roller 33, and then the other end also hits the nip portion, and finally the recording medium P The skew is corrected.

  As described above, in the present embodiment, even if the vertical registration once corrected at the position of the abutting member 32 is shifted later by performing the difference in the type of the recording medium P or the lateral registration correction, the registration roller 33. The vertical registration is corrected again at the position (the position immediately before the image transfer portion). That is, vertical registration correction is performed in two stages. Therefore, highly accurate vertical registration correction can be performed.

  As described above, the conveying device 30 according to the present embodiment includes the abutting member 32 (first vertical registration correction unit), the clamping roller 31 (horizontal registration correction unit), and the registration roller 33 (second vertical registration correction unit). Therefore, the positional deviation of the recording medium P conveyed toward the secondary transfer nip (image transfer unit) can be accurately corrected.

  In each of the above embodiments, the present invention is applied to an image forming apparatus using an intermediate transfer member such as the intermediate transfer belt 8 as an image carrier. On the other hand, the present invention can also be applied to an image forming apparatus using a photoreceptor such as a photoreceptor drum or a photoreceptor belt as an image carrier. Also in this case, the first vertical resist correction unit 32, the horizontal registration unit 32, and the horizontal registration unit 32 are transported to a transport device that transports the recording medium toward the image transfer unit in order to transfer the image formed on the photosensitive member onto the recording medium. By installing the resist correction means 31 and the second vertical resist correction means 33, the same effects as in the present embodiment can be obtained.

  Further, the present invention is not limited to the present embodiment, and it is obvious that the present embodiment can be modified as appropriate within the scope of the technical idea of the present invention, other than suggested in the present embodiment. is there. In addition, the number, position, shape, and the like of the constituent members are not limited to the present embodiment, and the number, position, shape, and the like suitable for implementing the present invention can be achieved.

1Y, 1M, 1C, 1K photosensitive drum,
8 Intermediate transfer belt (image carrier),
19 Secondary transfer roller (image transfer unit),
28 transport rollers,
30 transport device,
31 Nipping roller (horizontal registration correction means),
32 Abutting member (first vertical registration correction means),
33 Registration roller (second longitudinal registration correction means),
37 CIS (detection means),
38 Photosensor,
100 Image forming apparatus body (apparatus body), P recording medium.

Japanese Patent No. 2893540 JP 2002-265097 A

Claims (9)

A transport device that transports the recording medium toward an image transfer unit that transfers the image carried on the image carrier onto the recording medium,
First vertical registration correction means for correcting a positional deviation in the conveyance direction of the recording medium;
Lateral registration correction means for correcting the positional deviation in the width direction of the recording medium after the positional deviation in the transport direction is corrected by the first vertical registration correction means;
Second vertical registration correction means for correcting again the positional deviation in the conveyance direction of the recording medium after the positional deviation in the width direction has been corrected by the horizontal registration correction means;
A conveying apparatus comprising:   The transport apparatus according to claim 1, wherein the first vertical registration correction unit is an abutting member against which a leading end of the recording medium abuts, and is configured to be able to open and close a conveyance path of the recording medium.   The lateral registration correcting means is a sandwiching roller configured to be movable in the width direction after sandwiching the recording medium in a state of being abutted against the abutting member, and upstream of the abutting member in the conveyance direction of the recording medium. The transport apparatus according to claim 2, wherein the transport apparatus is disposed on a side. The second vertical registration correcting means is a registration roller disposed on the downstream side in the conveyance direction of the recording medium with respect to the abutting member,
The recording medium is conveyed toward the registration roller by the pinching roller in a state in which the conveyance path is opened by the abutting member, and positional deviation correction in the width direction is performed. Conveying device.   The conveying apparatus according to claim 4, wherein when the recording medium is conveyed to the image transfer unit by the registration roller, the nipping of the recording medium by the clamping roller is released. A detecting means for detecting a displacement in a width direction of the recording medium between the sandwiching roller and the registration roller;
6. The conveying apparatus according to claim 4, wherein the sandwiching roller performs positional deviation correction in the width direction of the recording medium based on a detection result of the detection unit.   The transport apparatus according to claim 4, wherein the registration roller can change a speed at which the recording medium is transported.   The transport apparatus according to claim 1, wherein the first vertical registration correction unit and the second vertical registration correction unit also correct skew of the recording medium.   An image forming apparatus comprising the transport device according to claim 1.

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