JP5919868B2 - Conveying apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to a conveyance device that conveys a recording medium, and an image forming apparatus such as a copying machine, a printer, a facsimile, or a multifunction machine or an offset printing machine provided with the same, and more particularly to a recording medium in a conveyance path. The present invention relates to a conveyance device that performs lateral registration correction and an image forming apparatus.

  Conventionally, in an image forming apparatus such as a copying machine or a printer, a position shift (hereinafter referred to as “lateral registration” as appropriate) in the width direction of the recording medium (a direction perpendicular to the transport direction) in the transport path. There is known a technique for correcting the position to a regular position (position shift correction) (see, for example, Patent Document 1).

  Specifically, in Patent Document 1, a recording medium conveyed along a conveyance path by a plurality of conveyance roller pairs hits a stopper (abutting member) and is subjected to vertical registration correction and skew correction. After that, the recording medium in contact with the stopper moves in the width direction while being sandwiched by a pair of lateral registration rollers (nip rollers) disposed upstream of the stopper, and the lateral registration is corrected. Will be. Thereafter, the recording medium in which the lateral resist is corrected is conveyed toward the image transfer unit.

  Here, in Patent Document 1, when lateral registration correction is performed, in order to reduce the conveyance resistance of the recording medium generated in the upstream conveyance path of the lateral registration roller pair, the upstream side of the lateral registration roller pair is described. A technique for forming a conveyance path in a straight shape or a large curved shape having a curvature radius of 50 mm or more is disclosed.

In the technique of Patent Document 1, since the conveyance resistance of the recording medium generated in the conveyance path on the upstream side of the lateral registration roller pair is reduced when the lateral registration correction is performed, the recording medium is skewed by the conveyance resistance. It can be expected to prevent the trapping or the accuracy of the lateral resist correction from being lowered.
However, since the conveyance path on the upstream side of the lateral registration roller pair is formed in a straight shape or a large curved shape having a curvature radius of 50 mm or more, the entire apparatus has been enlarged.

  The present invention has been made to solve the above-described problems, and does not increase the size of the apparatus and does not cause a problem that the recording medium is skewed due to the conveyance resistance. It is an object of the present invention to provide a conveyance device and an image forming apparatus.

According to a first aspect of the present invention, a conveying apparatus according to the first aspect of the present invention is a conveying apparatus that conveys a recording medium in a conveying path, and is formed so as to be movable in the width direction while sandwiching the recording medium, and rotates. The first clamping roller formed so as to be able to convey the recording medium, and the upstream side of the conveying path with respect to the first clamping roller, and is formed so as to be movable in the width direction while sandwiching the recording medium. And a second sandwiching roller formed so as to be able to transport the recording medium by rotating, and a state of being installed at a position downstream of the transport path with respect to the first sandwiching roller and closing the transport path; A state in which the recording medium is sandwiched between the abutting member formed so as to be movable so as to be switched between the opening state and the second sandwiching roller and the first sandwiching roller. A feed roller formed so as to be able to convey the recording medium by rotating and capable of switching between a state in which the recording medium is sandwiched and a state in which the recording medium is not sandwiched, and the transportation with respect to the abutting member A registration roller that is installed at a position downstream of the path so that the recording medium can be conveyed by rotating with the recording medium sandwiched therebetween, and a positional deviation in the width direction of the recording medium that is conveyed in the conveyance path. Detecting means for detecting the amount of the recording medium , wherein the first clamping roller is formed to be separable so as to be able to switch between a state in which the recording medium is sandwiched and a state in which the recording medium is not sandwiched, and the first clamping roller sandwiches the recording medium. The abutting member is moved so as to close the conveying path in a state of being separated so that the front end of the recording medium is abutted against the abutting member. The recording medium is conveyed by the feed roller so that the recording medium bends between the feed roller and the abutting member. After correcting the positional deviation in the oblique direction and correcting the positional deviation in the conveyance direction of the recording medium conveyed in the conveyance path and / or the positional deviation in the oblique direction with respect to the conveyance direction, the detection result of the detection unit is corrected. based in, in a state where the feed roller is spaced so as not to sandwich the recording medium, while holding the recording medium in the first nip roller and said second nip roller, said first nip roller The recording medium conveyed in the conveyance path is corrected by moving the second clamping roller in the width direction to correct the positional deviation in the width direction of the recording medium conveyed in the conveyance path. After correcting the positional deviation in the body width direction, when the recording medium is sandwiched between the registration rollers, the first sandwiching roller is separated so as not to sandwich the recording medium .

  In the present application, the “width direction” is defined as a direction orthogonal to the conveyance direction of the recording medium.

  In the present invention, a second clamping roller is installed on the upstream side of the first clamping roller, and a recording medium is arranged between the first clamping roller and the second clamping roller based on the amount of lateral registration displacement detected by the detecting means. The lateral registration correction is performed by moving the first sandwiching roller and the second sandwiching roller in the width direction in the sandwiched state. Accordingly, it is possible to provide a transport device and an image forming apparatus in which lateral registration correction is performed with high accuracy without causing a problem that the recording medium is skewed due to transport resistance without increasing the size of the device. Can do.

1 is an overall configuration diagram illustrating an image forming apparatus according to an embodiment of the present invention. It is a block diagram which shows a conveying apparatus. It is a top view which shows a part of conveying apparatus. It is the schematic which shows operation | movement of a conveying apparatus.

  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 FIG.
In FIG. 1, reference numeral 1 denotes an apparatus main body of a copying machine as an image forming apparatus, 2 an original reading unit that optically reads image information of an original D, and 3 an exposure light L based on image information read by the original reading unit 2. Is exposed to the photosensitive drum 5, 4 is an image forming unit for forming a toner image (image) on the photosensitive drum 5, and 7 is a toner image formed on the photosensitive drum 5 on the recording medium P. A transfer section (image forming section) for transferring, 10 a document transport section for transporting a set document D to the document reading section 2, and 12 to 14 a paper feed section for storing a recording medium P (sheet) such as transfer paper. (Paper feed cassette), 20 is a fixing device for fixing an unfixed image on the recording medium P, 21 is a fixing roller installed in the fixing device 20, 22 is a pressure roller installed in the fixing device 20, and 30 is recording. A transport device 45 for transporting the medium P along the transport path, Registration rollers for conveying the recording medium P toward the parts 7 (timing roller) shows.

With reference to FIG. 1, an operation during normal image formation in the image forming apparatus will be described.
First, the document D is conveyed from the document table in the direction of the arrow in the drawing by the conveyance roller of the document conveyance unit 10 and passes over the document reading unit 2. At this time, the document reading unit 2 optically reads the image information of the document D passing above.
Then, the optical image information read by the document reading unit 2 is converted into an electric signal and then transmitted to the exposure unit 3 (writing unit). An exposure light L (laser light) based on the image information of the electrical signal is emitted from the exposure unit 3 toward the photosensitive drum 5 of the image forming unit 4.

On the other hand, in the image forming unit 4, the photosensitive drum 5 is rotated in the clockwise direction in the drawing, and image information is transferred onto the photosensitive drum 5 through a predetermined image forming process (charging process, exposure process, development process). An image (toner image) corresponding to is formed.
Thereafter, the image formed on the photosensitive drum 5 is transferred onto the recording medium P conveyed by the registration roller 45 in the transfer unit 7 as an image forming unit.

On the other hand, referring to FIGS. 1 and 2, the recording medium P conveyed to the transfer unit 7 (image forming unit) operates as follows.
First, one of the plurality of paper feeding units 12 to 14 of the image forming apparatus main body 1 is automatically or manually selected (for example, the paper feeding unit 12 provided in the main body 1 is selected. )
Then, the uppermost sheet of the recording medium P stored in the paper feeding unit 12 is fed by the paper feeding roller 41 toward the curved conveyance path K1 where the first alignment assisting part 52A is installed.

  Thereafter, the recording medium P is a position of the merging portion X from the curved conveyance path K1 (the portion where the conveyance paths K3 and K4 from the two sheet feeding units 13 and 14 installed outside the apparatus main body 1 merge). After passing through the straight line, it passes through the straight conveyance path K2 in which the alignment unit 51 is installed, and reaches the position of the registration roller 45. Then, the recording medium P that has reached the position of the registration roller 45 is conveyed toward the transfer unit 7 (image forming unit) at the same timing in order to align with the image formed on the photosensitive drum 5. The

After the transfer process, the recording medium P passes through the position of the transfer unit 7 and then reaches the fixing device 20 through the conveyance path. The recording medium P that has reached the fixing device 20 is fed between the fixing roller 21 and the pressure roller 22, and the image is fixed by the heat received from the fixing roller 21 and the pressure received from both members 21 and 22. The The recording medium P on which the image has been fixed is delivered from between the fixing roller 21 and the pressure roller 22 (a nip portion) and then discharged from the image forming apparatus main body 1.
Thus, a series of image forming processes is completed.

Here, with reference to FIG. 2, the image forming apparatus 1 according to the present embodiment can feed the recording medium P from the three paper feeding units 12 to 14 toward the transfer unit 7 (image forming unit). It is configured.
Specifically, the first paper feed unit 12 is installed at a position below the apparatus main body 1. A curved conveyance path K1 (curve conveyance path) formed in a curved shape along the conveyance direction of the recording medium P is provided as a conveyance path from the first paper feeding unit 12 to the junction X. The curved conveyance path K1 is formed by a curved conveyance guide plate (not shown) (installed so as to sandwich the front and back surfaces of the recording medium P to be conveyed), and the conveyance roller pair 42 along the conveyance direction. A second clamping roller 32 (lateral registration correction auxiliary roller) is provided. Each of the conveying roller pair 42 and the second clamping roller 32 is a roller that is driven and rotated by a frictional resistance between the driving roller (not shown) and a driven roller. The recording medium P is conveyed while being sandwiched between two rollers. The second clamping roller 32 installed in the curved conveyance path K1 also functions as an alignment assisting part 52A (first alignment assisting part) for assisting the lateral registration correction operation. This will be explained in detail.
In the present embodiment, the curved conveyance path K1 is formed so that its radius of curvature is 50 mm or less. Therefore, the distance between the first paper feeding unit 12 and the merging unit X (or the aligning unit 51) is narrowed, and the image forming apparatus 1 (conveying device 30) is entirely downsized (compacted). .

Further, both of the second paper feed unit 13 and the third paper feed unit 14 are provided outside at positions on the side of the apparatus main body 1. A curved conveyance path K3 and a straight conveyance path are formed in the conveyance path from the second paper feeding unit 13 to the merging unit X, and the conveyance roller pair 43 and the second clamping roller 32 are installed. A straight conveyance path K4 is formed in the conveyance path from the third paper feed unit 13 to the junction X, and the conveyance roller pair 44 and the second clamping roller 32 are installed. The curved conveyance path K3 and the linear conveyance path K4 are respectively formed by a curved conveyance guide plate and a linear guide plate (both not shown). Each of the conveying roller pairs 43 and 44 and the second clamping roller 32 is a roller pair composed of a driving roller and a driven roller, and conveys the recording medium P while being sandwiched between two rollers. . The second clamping roller 32 is upstream of the junction X common to the conveyance path from the second sheet feeder 12 to the junction X and the conveyance path from the third sheet feeder 13 to the junction X. It is installed at a position near the curved conveyance path K3 and functions as an alignment assisting part 52B (second alignment assisting part) for assisting the lateral registration correction operation. Become.
In the present embodiment, the curved conveyance path K3 is formed so that its radius of curvature is 50 mm or less. Therefore, the distance between the second paper feeding unit 13 and the merging unit X (or the aligning unit 51) is narrowed, and the image forming apparatus 1 (conveying device 30) is downsized (compacted) as a whole. .
In the present embodiment, the curved conveyance path K3 and the straight conveyance path K4 are configured to be installed in the apparatus main body 1. However, the curved conveyance path K3, the straight conveyance path K4, and the two paper feeding units 13 and 14 are provided. Can be integrally configured as a paper feed unit (paper feed device) that can be attached to and detached from the apparatus main body 1. In that case, the apparatus main body 1 itself is further reduced in size.

  Further, the conveyance path from the junction X where the conveyance path from the first sheet feeding unit 12 and the conveyance path from the second and third sheet feeding units 13 and 14 merge to the position of the registration roller 45 is provided. As shown, a linear conveyance path K2 formed in a substantially linear shape along the conveyance direction of the recording medium P is provided. The linear transport path K2 is formed by a linear transport guide plate (not shown) (installed so as to sandwich the front and back surfaces of the recording medium P to be transported), and the feed roller 33 and the first roller along the transport direction. 1 Nipping roller 31 (lateral registration correction roller), abutting member 34 (stopper member), CIS 36 (detection means), and registration roller 45 are installed. Each of the feed roller 33, the first clamping roller 31, and the registration roller 45 is a roller pair composed of a driving roller and a driven roller, and conveys the recording medium P while being sandwiched between two rollers. Further, members such as the feed roller 33, the first clamping roller 31, the abutting member 34, and the CIS 36 installed in the linear conveyance path K2 are used for performing alignment operations such as vertical registration correction, skew feeding correction, and horizontal registration correction. This also functions as the matching unit 51, which will be described in detail later.

Next, with reference to FIG. 2 to FIG. 4, the conveyance device 30 that is characteristic in the present embodiment will be described in detail.
Hereinafter, the configuration in the conveyance path from the first paper feeding unit 12 to the registration roller 45 and the operation performed there will be mainly described.
Referring to FIGS. 2 and 3, the conveying device 30 includes a pair of conveying rollers 42 along the curved conveying path K <b> 1 along the conveying path of the recording medium P (the path indicated by the thick solid line in FIG. 2). A second nipping roller 32 (horizontal registration correction auxiliary roller) is installed, and a feed roller 33, a first nipping roller 31 (lateral registration correction roller), an abutting member 34, and a CIS 36 (contact) as detection means are provided on the linear conveyance path K2. An image sensor) and a registration roller 45 are installed.

Here, the abutting member 34 is located at a position downstream of the first clamping roller 31 in the conveyance path and relatively close to the first clamping roller 31, and closes and opens the conveyance path. It is formed to be movable so as to be able to switch between the states to be performed.
Specifically, the abutting member 34 is a metal plate having an abutting surface (in this embodiment, divided in the width direction) with which the leading end of the recording medium P abuts. The leading edge of the recording medium P abuts against the abutting member 34, and the vertical registration of the recording medium P is corrected. 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 34. The abutting member 34 is configured to open and close the conveyance path of the recording medium P. Specifically, the driving of a cam mechanism (not shown) that engages the abutting member 34 causes the abutting member 34 to move upward in FIG. 2 at a predetermined timing to close the conveyance path. 2 is moved downward to open the conveyance path.

  The feed roller 33 is located upstream of the first sandwiching roller 31 (upstream in the transport direction) and between the second sandwiching roller 32 and the first sandwiching roller 31. The feed roller 33 is formed so as to be able to convey the recording medium P by rotating in a state in which the recording medium P is sandwiched, and is formed to be separable so as to switch between a state in which the recording medium P is sandwiched and a state in which the recording medium P is not sandwiched. A pair of transport rollers. When the feed roller 33 sandwiches and conveys the recording medium P and abuts the leading end of the recording medium P against the abutting member 34, the feed roller 33 slightly contacts the recording medium P between the feed roller 33 and the abutting member 34. The conveyance time (driving time) is controlled so that bending (a buffer portion, which is a portion surrounded by a broken line in FIG. 4A) is formed.

  The first clamping roller 31 is a roller pair having a roller portion divided into a plurality of parts in the width direction, and is disposed upstream of the abutting member 34 in the conveyance direction of the recording medium P. The first clamping roller 31 is configured so as to be able to abut and disengage the roller pair by a drive mechanism (not shown) and to move in the width direction (in the direction of the broken line arrow S in FIG. 3). It is configured. That is, the first clamping roller 31 is formed to be separable so as to be able to switch between a state in which the recording medium P is sandwiched and a state in which the recording medium P is not sandwiched, and is formed to be able to transport the recording medium P by rotating. Then, the lateral registration of the recording medium P is corrected by moving in the width direction after sandwiching the recording medium P in a state where the first clamping roller 31 is in contact with the abutting member 34. That is, the first clamping roller 31 is formed so as to be movable in the width direction in a state where the recording medium P is sandwiched, and the recording medium P conveyed in the conveyance path is displaced in the width direction so that the width direction of the recording medium P is reached. It functions as a lateral registration correction means for correcting the positional deviation.

  The registration roller 45 is a pair of conveyance rollers disposed on the downstream side (downstream in the conveyance direction) of the conveyance path with respect to the first clamping roller 31 and the abutting member 34 and rotates in a state where the recording medium P is clamped. By doing so, the recording medium can be conveyed. Then, the recording medium P after the lateral registration is corrected by the first sandwiching roller 31 is conveyed to the position of the registration roller 45, and the state of being sandwiched by the registration roller 45 is a photo sensor (not shown, registration resist). When it is detected by the roller 45 and the image forming unit, the conveyance is temporarily stopped. Thereafter, the rotation timing of the registration roller 45 is started so as to match the image formed on the photosensitive drum 5, whereby the conveyance timing of the recording medium P conveyed toward the image forming unit is adjusted.

The CIS 36 as detection means is installed on the downstream side of the conveyance path with respect to the first clamping roller 31 and on the upstream side of the conveyance path with respect to the registration rollers 45. The CIS 36 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, and is a side end portion on one end side in the width direction of the recording medium P. By detecting the position of Pa (edge portion), the shift amount of the lateral resist is detected. That is, the CIS 36 (detection means) detects the amount of positional deviation in the width direction of the recording medium P that is transported in the transport path of the transport device 30. Based on the detection result of the CIS 36, lateral registration correction by the first clamping roller 31 (or lateral registration correction by the first clamping roller 31 and the second clamping roller 32) is performed.
In this embodiment, as shown in FIG. 3, the CIS 36 is installed only at one end in the width direction and the position of the side end Pa on the one end side in the width direction of the recording medium P is detected. It is also possible to detect the positions of the respective side end portions at both ends in the width direction of the recording medium P by installing over the entire area.

On the other hand, in the middle of the curved conveyance path K1 (curve), the second clamping roller 32 (first alignment assisting part 52A) and the conveyance roller pair 42 are installed.
The second sandwiching roller 32 is installed at a position sufficiently upstream of the first sandwiching roller 31 on the upstream side of the transport path. The second sandwiching roller 32 is configured to be able to abut and disengage the roller pair by a drive mechanism (not shown) and to be movable in the width direction (the direction perpendicular to the paper surface of FIG. 2). Has been. That is, like the first clamping roller 31, the second clamping roller 32 is formed so as to be separable so as to be able to switch between a state in which the recording medium P is sandwiched and a state in which the recording medium P is not sandwiched, and by rotating, the recording medium P It is formed to be transportable. When the predetermined condition is satisfied, the second sandwiching roller 32 moves in the width direction while sandwiching the recording medium P together with the first sandwiching roller 31 to correct the lateral registration of the recording medium P. That is, the second sandwiching roller 32 is formed to be movable in the width direction while sandwiching the recording medium P, and displaces the recording medium P transported in the transport path in the width direction under a predetermined condition. Thus, it functions as a lateral registration correction assisting means for correcting the positional deviation of the recording medium P in the width direction.
Further, the conveying roller pair 42 is installed at a position on the upstream side with respect to the second sandwiching roller, and is formed so as to be separable so as to be able to switch between a state in which the recording medium P is sandwiched and a state in which the recording medium P is not sandwiched.
In addition, in order to enable the conveyance device 30 to perform independent rotational driving (various rotational driving described later with reference to FIG. 4) of some of the plurality of roller pairs 31 to 33 and 42 to 45. A plurality of drive motors (drive mechanisms) are installed.

In the transport device 30 configured as described above, the first sandwiching roller in a state where the recording medium P is sandwiched between the first sandwiching roller 31 and the second sandwiching roller 32 based on the detection result of the CIS 36 (detection means). The positional deviation (lateral registration) in the width direction of the recording medium P conveyed in the conveyance path is corrected by moving the 31 and the second clamping roller 32 in the width direction.
As a specific example, referring to FIG. 3, the recording medium P is displaced by a distance α in the right direction in the drawing with respect to the reference position indicated by the alternate long and short dash line (a normal position having no positional deviation). When the state is detected by the CIS 36, the control unit sets the positional deviation amount α as a correction amount, and the first sandwiching roller 31 and the first sandwiching roller 31 while the recording medium P is sandwiched between the first sandwiching roller 31 and the second sandwiching roller 32. The second clamping roller 32 is moved by a distance α in the left direction in the figure.

As described above, the lateral registration correction is performed by sandwiching the recording medium P between the first sandwiching roller 31 and the second sandwiching roller 32 in the conveyance path from the second sandwiching roller 32 to the first sandwiching roller 31. This is when a recording medium P longer than the distance (for example, a long paper having a size in the transport direction of 900 mm or more) is transported.
That is, in the present embodiment, a recording medium P that is shorter than the distance of the transport path from the second sandwiching roller 32 to the first sandwiching roller 31 (for example, a sheet with a transport direction size of A4 short size). When transported, the first sandwiching roller 31 is moved in the width direction while the recording medium P is sandwiched only by the first sandwiching roller 31 based on the detection result of the CIS 36 (detection means), and transported in the transport path. The positional deviation of the recording medium P in the width direction is corrected.

  With such a configuration and operation, in the downsized image forming apparatus 1 (conveying device 30) in which the curved conveying path K1 having a radius of curvature of 50 mm or less is provided, the rear end thereof is positioned in the curved conveying path K1. Even when the lateral registration correction is performed on the recording medium P in the state, the position near the front end of the recording medium P is sandwiched by the first clamping roller 31 and the position near the rear end of the recording medium P (or Since the recording medium P is moved in the width direction in a state where the second holding roller 32 holds the position sufficiently away from the tip, the recording medium P is slidably contacted with the curved conveyance path K1 during the movement in the width direction. The resistance (conveyance resistance) generated by this can be reduced. For this reason, the recording medium is hardly skewed or twisted or wrinkled by the conveyance resistance, and the lateral registration correction is performed with high accuracy. Note that the force (clamping force) for sandwiching the recording medium P by the two sandwiching rollers 31 and 32 is set to be sufficiently large with respect to the conveyance resistance generated when the recording medium P slides on the curved conveyance path K1. ing.

When the recording medium P that is shorter than the distance of the transport path from the second sandwiching roller 32 to the first sandwiching roller 31 is transported, the recording medium P is generated on the recording medium P without interfering with the curved transport path K1. Since the lateral registration correction is performed in the linear transport path K2 having a small transport resistance, the lateral registration correction is performed with high accuracy without causing skew, twisting and wrinkling.
Note that the lateral registration correction control that is switched according to the size of the recording medium P in the conveyance direction described above is performed based on information about the size of the recording medium P input to the control unit. It may be based on information detected by a size detection sensor that directly detects the size of the recording medium P in the transport path from the paper unit 12 or the paper supply unit 12 to the alignment unit 51, or may be operated by the user on the operation panel. It may be based on the information of the recording medium P input from (not shown).

Although the case where the recording medium P is fed from the first paper feeding unit 12 has been described so far, the recording medium P is fed from the second paper feeding unit 13 or the third paper feeding unit 14. Similarly, when the recording medium P having a long size in the transport direction is transported, the lateral registration correction is performed by sandwiching the recording medium P between the first sandwiching roller 31 and the second sandwiching roller 32. become.
In particular, when the recording medium P is fed from the second paper feeding unit 13, the recording medium P is transported through the curved transport path K3 having a radius of curvature of 50 mm or less. The effect of will be demonstrated.
Further, when the recording medium P is fed from the third paper supply unit 14, the recording medium P is transported through the linear transport path K4, so that the transport resistance generated in the recording medium P does not increase in the first place. However, the occurrence of skew, twisting and wrinkles can be more reliably suppressed. In addition, since the alignment assisting part 52B (second clamping roller 32) is shared in the transport path from both the paper feeding units 13 and 14, the overall cost of the apparatus can be reduced and the size can be reduced. become.

  In the image forming apparatus 1 according to the present embodiment, the size in the transport direction of all the recording media P that can be passed is longer than the distance of the transport path from the second sandwiching roller 32 to the first sandwiching roller 31. In such a configuration, the lateral registration correction is always performed by sandwiching the recording medium P between the first sandwiching roller 31 and the second sandwiching roller 32.

Here, in the present embodiment, as described above, when the lateral registration correction is performed by sandwiching the recording medium P by the first sandwiching roller 31 and the second sandwiching roller 32 (or only by the first sandwiching roller 31). The other conveyance roller pair (feed roller 33 and conveyance roller pair 42) facing the recording medium P and capable of moving in the width direction when the lateral registration correction is performed while the recording medium P is sandwiched. The pair of transport rollers that are not provided are separated so as not to sandwich the recording medium P.
This ensures that the above-described lateral registration correction is performed.

In the present embodiment, before the lateral registration correction is performed by sandwiching the recording medium P by the first sandwiching roller 31 and the second sandwiching roller 32 (or the recording medium P is sandwiched by only the first sandwiching roller 31). Then, before the lateral registration correction is performed), the abutting member 34 is moved so as to close the conveyance path in a state where the first clamping roller 31 is separated so as not to clamp the recording medium P. The vertical registration correction (correction with respect to the positional deviation in the transport direction) and skew correction (correction with respect to the positional deviation in the oblique direction with respect to the transport direction) are performed by abutting the leading end of the recording medium P against the recording medium 34. .)
Accordingly, the vertical registration correction and the skew feeding correction are surely performed before the horizontal registration correction without disturbing the first clamping roller 31.

Further, in the present embodiment, in the state where the first sandwiching roller 31 and the second sandwiching roller 32 are rotated so as to be able to transport the recording medium P, the positional deviation amount in the width direction of the recording medium P is detected by the CIS 36 (detection means). Then, the lateral registration correction of the recording medium P is performed based on the detection result.
That is, when the lateral registration correction is performed by sandwiching the recording medium P between the first sandwiching roller 31 and the second sandwiching roller 32, the first sandwiching roller 31 and the second sandwiching roller 32 are driven to rotate, respectively. Perform while carrying P. Further, when the lateral registration correction is performed by sandwiching the recording medium P only by the first sandwiching roller 31, the first sandwiching roller 31 is rotationally driven to transport the recording medium P.
Accordingly, the lateral registration correction of the recording medium P can be performed without reducing the productivity of the apparatus as compared with the case where the lateral registration correction is performed by stopping the rotational driving of the first clamping roller 31 and the second clamping roller 32. it can.

In the present embodiment, after the above-described lateral registration correction is performed and the recording medium P subjected to lateral registration correction is sandwiched between the registration rollers 45 (conveying roller pair), the first sandwiching roller 31 is used. Are separated so as not to sandwich the recording medium P.
As a result, the conveyance process toward the image forming unit by the registration roller 45 is surely performed, and the operation of the alignment unit 51 for the recording medium P to be conveyed next is quickly prepared.

Hereinafter, an example of the operation of the transport device 30 configured as described above will be described in detail with reference to FIGS.
The operation of the transport device 30 described below is when the recording medium P is transported longer than the distance of the transport path from the second sandwiching roller 32 to the first sandwiching roller 31.
First, the recording medium P fed from the sheet feeding unit 12 is sandwiched and transported by a plurality of roller pairs 42, 32, and 33, and the leading end of the recording medium P abuts on the linear transport path K2 via the curved transport path K1. The position of the member 34 is reached (conveyance in the direction of the broken line arrow). At this time, the first clamping roller 31 moves away in the direction (in the direction of the solid arrow) that opens the transport path. Further, the abutting member 34 is moving in the direction of closing the conveyance path (in the direction of the white arrow and upward).
Then, as shown in FIG. 4A, the recording medium P stops when its leading end abuts against the abutting member 34. At this time, due to overrun of the feed roller 33, a predetermined deflection (a buffer portion, which is a portion surrounded by a broken line in FIG. 4A) is formed between the feed roller 33 and the abutting member 34. It is formed.
Thus, the vertical registration of the recording medium P is corrected. That is, after that, in the state where the positional deviation in the transport direction is corrected, the first clamping roller 31 is driven to rotate, and the recording medium P is transported toward the registration roller 45.
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 34. That is, even if the recording medium P is transported in an oblique posture with respect to the transport direction (even if it is skewed), one end of the leading end first strikes the abutting member 34 and eventually the other end is also centered on the one end. Abutting against the abutting member 34, the skew of the recording medium P is finally corrected.

After that, as shown in FIG. 4B, the recording medium P in which the tip is in contact with the abutting member 34 is in a state where the vertical registration correction and the skew correction are performed, It is nipped and conveyed by the second nipping roller 32. At this time, the abutting member 34 is moving in the direction of opening the conveyance path (in the direction of the white arrow and downward). Further, the feed roller 33 and the conveyance roller pair 42 are moved away from each other in a direction in which the conveyance path is opened and the recording medium P is not sandwiched (indicated by a solid arrow). The first sandwiching roller 31 and the second sandwiching roller 32 move in the direction (in the direction of the solid arrow) to close the conveyance path and sandwich the recording medium P, and start to rotate in the arrow direction. The
Then, the recording medium P is nipped and conveyed by the first nipping roller 31 and the second nipping roller 32, and the leading end of the recording medium P reaches the position of the CIS 36, and the position shift amount α of the lateral resist is detected at that position. Thus, based on the detection result, the first clamping roller 31 and the second clamping roller 32 move in the width direction (in the direction perpendicular to the paper surface (S direction)) in synchronization. That is, the displacement amount of the lateral registration of the recording medium P is detected by the CIS 36, and the two sandwiching rollers 31 and 32 move in the width direction synchronously so as to cancel the displacement amount (in the same direction and the same movement amount). Move.) Thus, the recording medium P is conveyed toward the registration roller 45 while performing lateral registration correction.

Thereafter, as shown in FIG. 4C, the front end of the recording medium P with the corrected lateral registration is sandwiched between the registration rollers 45 and is temporarily stopped. At this time, the first sandwiching roller 31 (or the first sandwiching roller 31 and another roller pair) that sandwiched and transported the recording medium P opens the transport path and does not sandwich the recording medium P. Move away in the direction (the direction of the solid arrow).
Thereafter, rotation of the registration roller 45 is started in synchronization with the image on the photosensitive drum 5, and the recording medium P is conveyed toward the transfer unit 7 (image transfer unit). Thus, the image is transferred to a desired position on the recording medium P.

In the transport device 30 configured and operated in this way, the accuracy of the operation of moving the second clamping roller 32 in the width direction based on the detection result of the CIS 36 (detection means) is the first clamping roller based on the detection result of the CIS 36. It can be set to be lower than the accuracy of the movement of 31 in the width direction. That is, the accuracy of the lateral registration correction by the first clamping roller 31 can be configured to be higher than the accuracy of the lateral registration correction by the second clamping roller 32.
As described above, when the lateral registration correction of the recording medium P is performed while being sandwiched between the first sandwiching roller 31 and the second sandwiching roller 32, the accuracy of the lateral registration correction by the first sandwiching roller 31 is the overall accuracy. This is because the accuracy of the lateral registration correction by the second clamping roller 32 assists it and does not require a very high correction accuracy.
With this configuration, for example, a low-priced drive motor can be used as a drive motor installed in a moving mechanism in which the second clamping roller 32 moves in the width direction, and the overall cost of the apparatus can be reduced.

  As described above, in the present embodiment, the second sandwiching roller 32 is installed on the upstream side of the first sandwiching roller 31, and based on the amount of lateral registration displacement detected by the CIS 36 (detecting means), In a state where the recording medium P is sandwiched between the first sandwiching roller 31 and the second sandwiching roller 32, the first sandwiching roller 31 and the second sandwiching roller 32 are moved in the width direction to perform lateral registration correction. Accordingly, the lateral registration correction can be performed with high accuracy without increasing the size of the apparatus and without causing a problem that the recording medium P is skewed due to the conveyance resistance.

In the present embodiment, the present invention is applied to the conveyance device 30 installed in the monochrome image forming apparatus 1. However, the present invention is naturally applied to the conveyance device installed in the color image forming apparatus. Can be applied.
Further, in the present embodiment, the present invention is applied to the conveyance device 30 installed in the electrophotographic image forming apparatus 1, but the application of the present invention is not limited to this, and other methods can be used. Even a transport device installed in an image forming apparatus (for example, an ink jet image forming apparatus or an offset printing machine) may be any transport device that performs lateral registration correction. Of course, the present invention can be applied to the above.
Even in those cases, the same effects as in the present embodiment can be obtained.

Further, in the present embodiment, the present invention is applied to the transport device 30 disposed upstream of the registration roller 45 in the transport direction, but the application of the present invention is not limited to this. Of course, the present invention can also be applied to all the transporting apparatuses provided at other positions as long as the transporting apparatus performs lateral registration correction.
Moreover, in this Embodiment, although this invention was applied with respect to the conveying apparatus 30 where two conveyance paths merge in the junction part X, the conveyance apparatus in which three or more conveyance paths merge in the junction part X, and a merge Naturally, the present invention can also be applied to a transport apparatus that is formed of only one transport path without the portion X.
Even in those cases, the same effects as in the present embodiment can be obtained.

In this embodiment, eight roller pairs 31 to 33 and 42 to 45 are installed in the conveying device 30. However, a larger number of roller pairs can be installed, or fewer roller pairs can be installed. You can also In that case, at least two of the plurality of roller pairs become the first sandwiching roller 31 and the second sandwiching roller 32. Further, in accordance with the transport state of the recording medium P transported on the transport path, an operation different from the operation of the transport device 30 described in FIG. 4 (for example, a separation operation of the second sandwiching roller 32 is performed, and various operations are performed. It is also possible to move the roller pair at different timings, etc.).
Even in those cases, the same effects as in the present embodiment can be obtained.

  It should be noted that 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.

1 image forming apparatus (apparatus body),
30 transport device,
31 First clamping roller (lateral registration correction roller),
32 Second clamping roller (lateral registration correction auxiliary roller),
33 Feed roller (conveying roller pair),
34 Abutting member,
36 CIS (detection means),
45 Registration roller (conveying roller pair),
51 alignment section,
52A 1st alignment assistance part, 52B 2nd alignment assistance part,
K1, K2 curved conveyance path, K3 linear conveyance path,
X junction, P recording medium (sheet).

JP 2008-50069 A

Claims (7)

A transport device for transporting a recording medium in a transport path,
A first clamping roller formed so as to be movable in the width direction in a state where the recording medium is sandwiched, and capable of conveying the recording medium by rotating;
The first clamping roller is installed on the upstream side of the conveyance path, and is formed so as to be movable in the width direction while sandwiching the recording medium, and is formed so as to be able to convey the recording medium by rotating. Two clamping rollers;
An abutting member that is installed at a position downstream of the conveying path with respect to the first clamping roller and is configured to be movable so as to be able to switch between a closed state and an opened state of the conveying path;
A state where the recording medium is transported by being rotated in a state where the recording medium is sandwiched and installed in a position between the second sandwiching roller and the first sandwiching roller, and the recording medium is sandwiched; A feed roller formed so as to be separable so as to be able to switch between a state in which it is not sandwiched;
A registration roller that is installed at a position downstream of the abutting member with respect to the abutting member, and is formed so that the recording medium can be conveyed by rotating in a state of sandwiching the recording medium;
Detection means for detecting a positional deviation amount in the width direction of the recording medium conveyed in the conveyance path;
With
The first clamping roller is formed to be separable so as to switch between a state in which the recording medium is sandwiched and a state in which the recording medium is not sandwiched,
In a state where the first clamping roller is separated so as not to clamp the recording medium, the abutting member is moved so as to close the conveyance path, and the leading end of the recording medium is abutted against the abutting member. When the recording medium is conveyed by the feed roller so that the bending of the recording medium is formed between the feed roller and the abutting member, the recording medium is displaced in the conveying direction or / and in the conveying direction. Correct the positional deviation in the diagonal direction,
After correcting the positional deviation in the conveying direction of the recording medium conveyed in the conveying path and / or the positional deviation in the oblique direction with respect to the conveying direction , the feed roller is moved to the recording medium based on the detection result of the detecting means. the a state spaced so as not to sandwich, while holding the recording medium in the first nip roller and said second nip roller, and said second nip roller and said first nip roller in the widthwise direction To correct the positional deviation in the width direction of the recording medium conveyed in the conveyance path ,
After the positional deviation in the width direction of the recording medium conveyed in the conveyance path is corrected, when the recording medium is sandwiched between the registration rollers, the first sandwiching roller does not sandwich the recording medium. The conveying apparatus characterized by being spaced apart .   When a recording medium shorter than the distance of the conveying path from the second clamping roller to the first clamping roller is conveyed, the recording medium is clamped only by the first clamping roller based on the detection result of the detection means. 2. The transport device according to claim 1, wherein the first sandwiching roller is moved in the width direction in a state where the recording medium is transported to correct a positional shift in the width direction of the recording medium transported in the transport path. The detection means is installed on the downstream side of the transport path with respect to the abutting member,
In the state where the first clamping roller and the second clamping roller are rotated so as to be able to convey the recording medium, the detection unit detects a positional shift amount of the recording medium in the width direction, and the recording based on the detection result. The transport apparatus according to claim 1, wherein a positional deviation in the width direction of the medium is corrected. The accuracy of the movement of the second clamping roller in the width direction based on the detection result of the detection means is compared with the accuracy of the movement of the first clamping roller in the width direction based on the detection result of the detection means. The conveying apparatus according to any one of claims 1 to 3, wherein the conveying apparatus is set to be low. The first clamping roller is installed in a linear conveyance path formed linearly along the conveyance direction,
5. The transport device according to claim 1, wherein the second sandwiching roller is installed in a curved transport path formed in a curved shape along the transport direction or in the vicinity thereof. The transport apparatus according to claim 5, wherein the curved transport path is formed so that a curvature radius thereof is 50 mm or less. An image forming apparatus comprising the transport device according to claim 1.

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