JP2016088702A - Conveyance device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a conveyance device and an image forming apparatus performing skew correction and lateral registration correction of a recording medium with good responsiveness and with high accuracy without deteriorating productivity of the devices and without increasing sizes and cost of the devices.SOLUTION: A holding frame 72 which rotatably holds a holding roller 31 and is supported on a base frame 71 via a free bearing includes a support shaft 73 fitted to a guide section 71a of the base frame 71. The holding frame 72 is rotated with the support shaft 73 as a center by second driving means installed in the base frame 71 on the basis of a detection result of a skew detection sensor 35 so as to rotate the holding roller 31 in an oblique direction together with the holding frame 72. The support shaft 73 is moved along a guide section 71a by third driving means installed in the base frame 71 on the basis of a detection result of CIS36 so as to move the holding roller 31 in a width direction together with the holding frame 72.SELECTED DRAWING: Figure 3

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 skew correction, and an image forming apparatus.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine or a printer, a positional deviation (skew) in a diagonal direction of a recording medium is corrected in a conveyance path, and the width direction of the recording medium (a direction perpendicular to the conveyance direction). There is known a technique for correcting the deviation of the position (hereinafter referred to as “lateral resist” as appropriate) to a regular position (see, for example, Patent Documents 1 and 2).

Specifically, the image forming apparatus disclosed in Patent Document 1 is provided with a correction unit that performs skew correction and lateral registration correction. The correction unit includes a conveyance roller (clamping roller) that conveys the recording medium, a CD moving frame (holding member) that rotatably holds the conveyance roller, and a CD moving frame that is movably held in the width direction and is conveyed. A skew correction frame in which a motor for rotationally driving a roller and a motor for moving a CD moving frame in the width direction are respectively installed, and a motor for rotating the skew correction frame while holding the skew correction frame rotatably in an oblique direction And a base plate (frame) on which is installed.
Based on the detection result detected by the skew sensor (first detection means), the skew correction frame is rotated to perform skew correction (skew correction), and further detected by the CD sensor (second detection means). The lateral registration correction is performed by sliding the CD moving frame based on the detection result. Thereafter, the recording medium in which the skew feeding and the horizontal registration are corrected is conveyed toward the image forming unit.

The above-described conventional technique is provided with a correction unit that performs skew feeding correction and lateral registration correction, and performs skew feeding correction and lateral registration correction of the recording medium almost simultaneously while transporting the recording medium without stopping. Therefore, an effect of improving the productivity of the apparatus can be expected as compared with the case where the recording medium is temporarily stopped and the skew feeding correction and the lateral registration correction are performed at different timings.
However, since the skew correction frame that holds the CD moving frame (holding member) that holds the transport roller so as to be movable in the width direction is provided with two motors, the skew correction frame is increased in weight and size. As a result, there have been problems such as an increase in the size and cost of the motor that rotates the skew correction frame, and a decrease in responsiveness when rotating the skew correction frame.

  The present invention has been made to solve the above-described problems, and does not reduce the productivity of the apparatus, and does not increase the size and cost of the apparatus. An object of the present invention is to provide a transport device and an image forming apparatus in which correction is performed with high responsiveness and high accuracy.

  A transport apparatus according to a first aspect of the present invention is a transport apparatus that transports a recording medium in a transport path, and detects a positional deviation amount of the recording medium transported in the transport path in an oblique direction. Detection means, second detection means for detecting the amount of positional deviation in the width direction of the recording medium conveyed in the conveyance path, and a clamping roller that is rotationally driven by the first driving means and conveys the recording medium in a nipped state And a holding member that rotatably holds the pinching roller, and a relay that is installed on a frame of the apparatus and supports the holding member so that the holding member can move in either a width direction or an oblique direction with respect to the frame. A support member, and the holding member includes a support shaft that is fitted to a guide portion that is formed to extend in the width direction of the frame, and is disposed on the frame, Second driving means configured to rotate the holding roller together with the holding member in an oblique direction by rotating the holding member around the support shaft based on a detection result of the first detection means; A third frame is installed on the frame and configured to move the holding roller in the width direction together with the holding member by moving the support shaft along the guide portion based on the detection result of the second detection means. Driving means.

  According to the present invention, it is possible to carry out the skew correction and lateral registration correction of a recording medium with high responsiveness and high accuracy without reducing the productivity of the apparatus and without increasing the size and cost of the apparatus. An apparatus 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 the schematic which shows a conveying apparatus. It is a top view which shows a part of conveying apparatus. It is a block diagram which shows the principal part of a conveying apparatus. It is a schematic top view which shows the principal part of a conveying apparatus. It is a figure which shows the state in which the holding member was supported on the flame | frame by the relay support member in the conveying apparatus. It is a block diagram which shows a two-stage spline coupling. The holding member is (A) the figure which operates in the width direction, (B) the figure which operates in the diagonal direction, and (C) the figure which operates in the width direction and the diagonal direction simultaneously. It is the schematic which shows operation | movement of a conveying apparatus. FIG. 10 is a schematic diagram illustrating an operation of the conveyance device following FIG. 9. It is a block diagram which shows the principal part of the conveying apparatus as a modification.

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 overall configuration and operation of the image forming apparatus will be described with reference to FIG.
In FIG. 1, 1 is a copying machine as an image forming apparatus, 2 is a document reading unit that optically reads image information of a document D, and 3 is a photosensitive member that exposes light L based on the image information read by the document reading unit 2. An exposure unit for irradiating the drum 5, 4 is an image forming unit for forming a toner image (image) on the photosensitive drum 5, and 7 is a transfer for transferring the toner image formed on the photosensitive drum 5 to the recording medium P. Section (image forming section), 10 is a document transport section that transports a set document D to the document reading section 2, and 12 to 14 are sheet feeding sections (sheet feeding) in which a recording medium P (sheet) such as transfer paper is stored. 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 a recording medium P. A transport device 31 for transporting along the transport path, 31 is a transfer unit 7 (image Registration rollers (nip roller that serves as a timing roller) for conveying the recording medium P toward the forming unit) (horizontal resist skew correction 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 sandwiching roller 31 functioning as a registration roller 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 feed unit 12 is directed by the paper feed roller 41 toward the curved conveyance path where the first conveyance roller pair 42 and the second conveyance roller pair 43 are installed. Be fed.

  Thereafter, the recording medium P passes through the curved conveyance path through the position of the merging portion X (the portion where the conveyance paths from the two paper feeding units 13 and 14 installed outside the apparatus main body 1 merge). The third conveying roller pair 44 and the linear conveying path on which the aligning unit 51 is installed pass through and reach the position of the sandwiching roller 31 constituting the aligning unit 51. Then, the skew feeding correction and the lateral registration correction are performed by the sandwiching roller 31 constituting the aligning unit 51, and further, the transfer unit is aligned with the timing in order to align with the image formed on the photosensitive drum 5. 7 (image forming unit).

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.
Further, the conveyance roller pairs 42 to 44 (including a conveyance roller pair not attached with a reference numeral) installed in the conveyance device 30 are all drive rollers (rollers driven by a drive mechanism (not shown)). And a driven roller (a roller that is driven to rotate by frictional resistance with the driving roller), and is configured to be able to convey the recording medium P while being sandwiched between the two rollers.

  Here, the transfer unit 7 (image forming unit) starts 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. As a transport path up to, a linear transport path formed in a substantially straight line along the transport direction of the recording medium P is provided. This linear transport path is formed by a linear transport guide plate (not shown) (installed so as to sandwich the front and back surfaces of the transported recording medium P), and the third transport roller pair 44 along the transport direction. , CIS 36 (second detection means), skew detection sensor 35 (first detection means), and clamping roller 31 (alignment portion 51) are installed. Each of the third transport roller pair 44 and the sandwiching roller 31 is a roller pair composed of a driving roller and a driven roller, and transports the recording medium P while being sandwiched between the two rollers. The sandwiching roller 31 performs an alignment operation between skew correction (correction for a positional deviation in the oblique direction with respect to the conveyance direction) and lateral registration correction (correction for a positional deviation in the width direction). This will also function as the matching unit 51, which will be described in detail later.

Next, with reference to FIGS. 2 to 10, the conveyance device 30 that is characteristic in the present embodiment will be described in detail.
Hereinafter, the configuration in the transport path from the junction X to the transfer unit 7 (image forming unit) and the operations performed there will be mainly described.
2 and 3, the conveyance device 30 includes a third conveyance roller pair 44, along a linear conveyance path of the recording medium P (a conveyance path from the merging portion X to the transfer portion 7). CIS 36 (contact image sensor) as second detection means, skew detection sensor 35 as first detection means, and sandwiching roller 31 (horizontal registration / skew correction that functions as a registration roller 51 as well as a registration unit 51) Laura) is installed.

Here, the sandwiching roller 31 is a roller pair having a roller portion divided into a plurality of parts in the width direction, and is a driving roller that is rotationally driven by a first motor 61 (see FIG. 4) as a first driving means. 31b and a driven roller 31a that rotates following the rotation of the driving roller 31b. The sandwiching roller 31 is formed so as to be able to transport the recording medium P by rotating in a state where the recording medium P is sandwiched.
In the present embodiment, a pair of rollers having a plurality of roller portions divided in the width direction is used as the sandwiching roller 31, but a pair of rollers having a roller portion extending in the width direction without being divided in the width direction. (The clamping roller 31 shown in FIG. 11 can be referred to.).

In addition, the holding roller 31 is formed so as to be able to rotate in an oblique direction (in the direction of the broken line double arrow W in FIG. 3) around the support shaft 73 together with a holding frame 72 as a holding member. It is formed so that it can move in the direction of the broken line arrow S in FIG.
The sandwiching roller 31 rotates around the support shaft 73 together with the holding frame 72 based on the detection result of the skew detection sensor 35 as the first detection means, and performs skew correction of the recording medium P. Based on the detection result of the CIS 36 as the second detection means, the recording medium P is moved along the guide portion 71a together with the holding frame 72 to perform lateral registration correction.

Specifically, with reference to FIGS. 4 to 6, the sandwiching roller 31 (the driven roller 31 a and the driving roller 31 b) is rotatably supported by a holding frame 72 as a holding unit. The holding frame 72 (holding portion) is formed by forming a sheet metal in a substantially box shape, and has both ends in the width direction (the vertical direction in FIG. 2 and the left-right direction in FIGS. 4 to 6). The shaft portion of the pinching roller 31 (the driven roller 31a and the driving roller 31b) is inserted into the hole portion formed in the portion through a bearing. The holding frame 72 moves in the width direction together with the sandwiching roller 31 and rotates around the support shaft 73.
At one end in the width direction of the driving roller 31b, the driving roller 31b is fixedly installed on a bracket 69 in a frame (a main body frame 70, a base frame 71, a bracket 69 and the like are fixed by screw fastening). The first drive means (comprised of the first motor 61, gear trains 66, 67, etc.) is connected via a two-stage spline coupling 65. As a result, the rotational driving force of the first motor 61 fixed to the frames 69 to 71 of the transport device 30 is transmitted to the driving roller 31b via the gear trains 66 and 67 and the two-stage spline coupling 65, and the pinching roller 31 Is driven to rotate.
In addition, an encoder 96 for controlling the rotation speed and rotation timing of the pinching roller 31 (drive roller 31b) is installed on the other end side in the width direction of the drive roller 31b.

Here, as shown in FIG. 7, the two-stage spline coupling 65 includes a first spline gear 65a, a second spline gear 65b, an intermediate spline gear 65c, a guide ring 65d, and the like.
The first spline gear 65a is an external gear, and is rotatably held by a rotating shaft 68 (with a bracket 69 via a bearing) that rotates together with one gear 67 of the gear trains 66 and 67 of the first driving means. )).
The second spline gear 65 b is an external gear and is installed on the shaft portion of the drive roller 31 b of the pinching roller 31.
The intermediate spline gear 65c is an internal gear and extends in the width direction so as to mesh with the two spline gears 65a and 65b even if the clamping roller 31 (holding frame 72) moves (slides) in the width direction. Has been. Further, the two spline gears 65a and 65b are formed in a crown shape so as to mesh with the intermediate spline gear 65c even when the sandwiching roller 31 (holding frame 72) rotates in an oblique direction.
By using such a two-stage spline coupling 65, even if the clamping roller 31 rotates about the support shaft 73 in a substantially horizontal plane direction or slides in the width direction, the frames 69 to 71 of the main body. The driving force of the first motor 61 (first driving means) fixedly installed on the motor is reliably and accurately transmitted to the clamping roller 31 (driving motor 31b), and the clamping roller 31 is driven to rotate well. become.
The guide ring 65d is a substantially annular stopper member, and is provided in order to prevent the two spline gears 65a and 65b from moving relative to each other in the width direction and falling off the two-stage spline coupling 65. The spline gear 65c is installed at both ends in the width direction.

5 and 6, the holding frame 72 (holding member) has a free bearing 95 (ball transfer) as a relay support member installed on the frames 69 to 71 (base frame 71) of the apparatus. The frame 69 to 71 (base frame 71) are supported so as to be movable in both the width direction and the oblique direction (so that the plane perpendicular to the paper surface of FIG. 6 can be moved freely). Supported). In FIG. 4, the illustration of the free bearing 95 is omitted to make it easy to visually recognize other components.
Here, the free bearing 95 (ball transfer) is a known bearing in which a steel ball 95a (sphere) is inserted into the recess of the pedestal 95b, and the top of the steel ball 95a makes point contact with the bottom surface of the holding frame 72. It will be. Three or more free bearings 95 as relay support members are arranged so as to support the holding frames 72 at three or more positions with respect to the frames 69 to 71 (base frame 71) (this embodiment). Then, four free bearings 95 are installed.) In the present embodiment, as shown in FIG. 5, positions corresponding to the four corners on the bottom surface of the holding frame 72 (positions at which the holding frame 72 can be contacted even if it is slid or rotated to the maximum) are respectively provided. A free bearing 95 is fixedly installed on the base frame 71.
In this way, by supporting the holding frame 72 with respect to the base frame 71 via the free bearing 95, even if the holding frame 72 moves relative to the base frame 71 in the surface direction, the friction generated thereby. Since the load can be made extremely small, lateral registration correction and skew correction (skew correction) to be described later are performed with high responsiveness and high accuracy.

Here, referring to FIG. 4, FIG. 5, etc., the holding frame 72 (holding member) is fitted into a guide portion 71a formed to extend in the width direction in the base frame 71 (main body frame). A supporting shaft 73 (stud) is provided.
Specifically, on the bottom surface of the holding frame 72, a support shaft 73 (stud) is erected downward at a position relatively close to the end of the drive side (right side in FIGS. 4 and 5). Is fixed by caulking or the like. On the other hand, on the ceiling surface of the base frame 71, a guide portion 71a (a substantially rectangular hole portion) is located at a position relatively close to the end portion on the driving side (on the right side in FIGS. 4 and 5). Is formed. Then, the support shaft 73 of the holding frame 72 is fitted into the guide portion 71a (hole portion) of the base frame 71 via a guide roller 76 (a roller-shaped member rotatably installed on the support shaft 73). It is formed to do. Then, the holding frame 72 slides in the width direction in conjunction with the movement of the support shaft 73 along the guide portion 71 a together with the holding roller 31, and rotates around the support shaft 73.
In the present embodiment, the guide portion 71a with which the support shaft 73 of the holding frame 72 is fitted is a substantially shaped hole portion. However, the guide portion 71a may enable the operation of the holding frame 72 described above. For example, without being limited thereto, the guide portion 71a can be formed in a substantially elongated hole shape, or the guide portion 71a can be a groove portion.

With such a configuration, the second drive means 63, 81 to 84, 98 installed on the base frame 71 (main body frame) allows the holding frame based on the detection result of the skew detection sensor 35 (first detection means). By rotating 72 around the support shaft 73, the holding roller 31 and the sandwiching roller 31 are rotated in an oblique direction.
Further, the support shaft 73 is moved along the guide portion 71a based on the detection result of the CIS 36 (second detection means) by the third drive means 62, 74, 97 installed on the base frame 71 (frame of the main body). As a result, the clamping roller 31 is moved in the width direction together with the holding frame 72.

Specifically, the second driving means is for rotating the holding frame 72 (the clamping roller 31) around the support shaft 73, and includes a second motor 63, a timing belt 98, a first cam 84, a first cam. It comprises a first tension spring 92 as an urging member, a lever member 81 (rotating lever), and the like.
The first tension spring 92 as the first urging member urges the holding frame 72 in an obliquely forward direction (clockwise around the support shaft 73 in FIG. 5). And the base frame 71.
The first cam 84 is held by the base frame 71 so as to be rotatable about the rotation support shaft 84a, and the holding frame 72 biased in the forward direction of the diagonal direction by the first tension spring 92 is reversed in the diagonal direction. It is pushed indirectly via the lever member 81 in the counterclockwise direction around the support shaft 73 in FIG. In other words, the second drive means is configured to push the holding frame 72 via the lever member 81.
The lever member 81 is held by the base frame 71 so as to be rotatable about a rotation support shaft 81a, and a cam follower 82 (first roller-shaped member) that contacts the first cam 84 is rotatably installed at one end thereof. On the other end side, an action roller 83 (second roller-shaped member) that abuts against the protrusion 72a of the holding frame 72 is rotatably installed (axially supported).
The second motor 63 is fixedly installed on the base frame 71. A timing belt 98 is wound around the drive pulley installed on the motor shaft of the second motor 63 and the driven pulley installed on the rotation support shaft 84 a of the first cam 84.

  With such a configuration, referring to FIG. 8B, when the second motor 63 is driven, the rotational driving force is transmitted to the first cam 84 via the timing belt 98, and the lever member 81 is moved. The holding frame 72 is pushed by the lever member 81 at the position of the protrusion 72 a by being pushed by the first cam 84 and pivoting about the rotation support shaft 81 a, and the spring force of the first tension spring 92 is increased. The holding frame 72 rotates to resist.

The first cam 84 and the lever member 81 (cam follower 82) are always in contact with each other by the spring force of the first tension spring 92, and the holding frame 72 (projecting portion 72a) and the lever member 81 ( It is always in contact with the action roller 83), and the rotation angle (posture in the rotation direction) of the holding frame 72 around the support shaft 73 depending on the rotation angle (posture in the rotation direction) of the first cam 84. Will be determined.
As described above, the cam follower 82 as the first roller-shaped member is installed at the contact position between the first cam 84 and the lever member 81, and the contact position between the holding frame 72 (protrusion 72 a) and the lever member 81 is set. By installing the action roller 83 as the second roller-shaped member, the frictional load generated at each contact position can be extremely reduced, so that skew correction (skew correction) is performed with high responsiveness and high accuracy. It will be.

In the present embodiment, as shown in FIG. 4, an encoder wheel 86 is installed on the rotation support shaft 84 a of the first cam 84, and an encoder sensor 87 is fixed at the position of the base frame 71 corresponding thereto. Then, the rotation angle (posture in the rotation direction) of the first cam 84 (holding frame 72) is adjusted and controlled by the control of the second motor 63 based on the detection of the encoder wheel 86 by the encoder sensor 87, and the recording medium P is skewed. Correction will be performed.
Here, the first cam 84 is formed so that its cam curve becomes a constant velocity cam curve. As a result, the amount of change in the rotation angle of the first cam 84 and the amount of change in the rotation angle of the holding frame 72 can be proportional to each other, so that the skew correction control of the recording medium P is performed with high accuracy. be able to.

On the other hand, the third driving means is for slidably moving the holding frame 72 (the sandwiching roller 31) in the width direction together with the support shaft 73 moving along the guide portion 71a. The second cam 74, the second tension spring 91 as the second urging member, and the like.
The second tension spring 91 as the second urging member is connected to the holding frame 72 and the base frame 71 so as to urge the holding frame 72 in the positive direction of the width direction (the left direction in FIG. 5). Has been.
The second cam 74 is held by the base frame 71 so as to be rotatable about the rotation support shaft 74a, and the holding frame 72 biased in the forward direction in the width direction by the second tension spring 91 is reversed in the width direction. (It is the right direction in FIG. 5). A cam follower 75 is installed (axially supported) on the support shaft 73 of the holding frame 72 at a position where it abuts on the second cam 74, and at a position where it abuts on the guide portion 71a (base frame 71), a guide roller 76 (roller) is provided. (Like member) is installed (axially supported).
The third motor 62 is fixedly installed on the base frame 71. A timing belt 97 is wound around the drive pulley installed on the motor shaft of the third motor 62 and the driven pulley installed on the rotation support shaft 74 a of the second cam 74.

  With this configuration, referring to FIG. 8A, when the third motor 62 is driven, the rotational driving force is transmitted to the second cam 74 via the timing belt 97, and the second cam 74 is driven. As a result, the holding frame 72 slides so as to resist the spring force of the second tension spring 91.

The second cam 74 and the support shaft 73 (cam follower 75) are always in contact with each other by the spring force of the second tension spring 91, and depending on the rotation angle of the second cam 74 (posture in the rotation direction). The moving distance (position in the width direction) of the holding frame 72 (support shaft 73) is determined.
As described above, since the second cam 74 and the support shaft 73 are in contact with each other via the cam follower 75 as a roller-shaped member, the friction load generated at the contact position can be extremely reduced. The resist correction is performed with high response and high accuracy.

In the present embodiment, as shown in FIG. 4, an encoder wheel 77 is installed on the rotation support shaft 74 a of the second cam 74, and an encoder sensor 78 is fixed at the position of the base frame 71 corresponding thereto. Then, the rotation angle (posture in the rotation direction) of the second cam 74 is adjusted and controlled by the control of the third motor 62 based on the detection of the encoder wheel 77 by the encoder sensor 78, and the recording medium P of the recording medium P by the sliding movement of the holding frame 72 is controlled. Lateral registration correction is performed.
Here, the 2nd cam 74 is formed so that the cam curve may become a constant velocity cam curve. As a result, the amount of change in the rotation angle of the second cam 74 and the amount of change in the movement distance of the holding frame 72 can be made proportional to each other, so that the lateral registration correction control of the recording medium P is performed with high accuracy. be able to.

FIG. 8C is a diagram illustrating an example of the operation of the holding frame 72 when the skew feeding correction and the lateral registration correction of the recording medium P described above are performed at the same time.
As shown in FIG. 8C, when the second motor 63 is driven to rotate the first cam 84, the lever member 81 is pushed by the first cam 84 and rotates around the rotation support shaft 81a. As a result, the holding frame 72 is pushed by the lever member 81 at the position of the protrusion 72 a, and the holding frame 72 rotates to resist the spring force of the first tension spring 92. At the same time, when the third motor 62 is driven and the second cam 74 is rotated, the holding frame 72 slides and moves against the spring force of the second tension spring 91 by the second cam 74. At this time, the action roller 83 of the lever member 81 pushes the protrusion 72a (holding frame 72) while moving on the surface of the protrusion 72a.

As described above, in the present embodiment, since the support shaft 73 serving as the rotation fulcrum fixed to the holding frame 72 that rotatably holds the clamping roller 31 is slid, the rotation operation is performed with respect to one holding frame 72. And shift operation (slide movement) are possible. For this reason, it is not necessary to install either the second driving means for rotating the pinching roller 31 or the third driving means for shifting the pinching roller 31 on the holding frame 72, and it is fixed to the main body. It can be installed on the other frame (base frame 71). Accordingly, the structure that rotates and slides can be reduced in weight, so that the responsiveness of these operations can be improved, and the driving source of the second driving means and the third driving means (the second motor 63, The power of the third motor 62) can be reduced, and the size and cost of the apparatus can be reduced. In the present embodiment, the first driving means for rotationally driving the clamping roller 31 is also installed in the frame (bracket 69) of the apparatus, not in the holding frame 72, so that the above-described effects can be further ensured. Will be demonstrated.
Further, since the support shaft 73 is shifted and moved by the second cam 74, the contact point between the second cam 74 and the holding frame 72 to be moved becomes one point, and even if the support shaft 73 rotates, the second cam 74 rotates. The support shaft 73 can be smoothly moved along the guide portion 71 a while sliding on one point on the surface of the two cams 74. Further, since the first cam 84 is in contact with the lever member 81 to be rotated at one point, even if the holding frame 72 is shifted, the lever member 81 (holding is held while sliding one point on the surface of the first cam 84). The frame 72) can be rotated while being shifted smoothly.

The sandwiching roller 31 corrects the positional displacement amount of the recording medium in the oblique direction based on the detection result of the skew detection sensor 35 (first detection means) while transporting the recording medium P in the sandwiched state. Become. That is, the sandwiching roller 31 functions as means for performing skew correction (skew correction) of the recording medium P by displacing the recording medium P conveyed in the conveyance path in an oblique direction.
Further, the nipping roller 31 corrects the positional displacement amount in the width direction of the recording medium P based on the detection result of the CIS 36 (second detecting means) while transporting the recording medium P in the nipped state. In other words, the pinching roller 31 also functions as means for correcting the lateral registration of the recording medium P by displacing the recording medium P conveyed in the conveyance path in the width direction.

  Here, the third transport roller pair 44 is installed at a position upstream of the sandwiching roller 31 (upstream in the transport direction). The third conveying roller pair 44 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 separated 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. It is a pair of conveyance rollers formed so as to be possible. When the recording medium P reaches the position of the sandwiching roller 31 and is sandwiched and transported by the sandwiching roller 31, the third transport roller pair 44 is switched from the state in which the recording medium P is sandwiched to the state in which it is not sandwiched. become.

Further, in the present embodiment, the sandwiching roller 31 is a pair of conveyance rollers that is disposed at a position upstream of the conveyance path with respect to the transfer unit 7 (image forming unit) and also functions as a registration roller. By rotating the recording medium P in a sandwiched state, the recording medium P (the recording medium P after the skew feeding correction and the lateral registration correction are performed by the sandwiching roller 31 itself) is conveyed toward the image forming unit.
Here, the first motor 61 that rotationally drives the nipping roller 31 (drive motor 31b) is a drive motor with variable rotation speed, and is formed so that the conveyance speed of the recording medium P can be varied. When a timing at which the recording medium P is conveyed to the position of the nipping roller 31 is detected by a paper detection sensor (photo sensor) (not shown) (the recording medium P is conveyed to the position of the nipping roller 31 and the nipping roller 31 is moved). When the state where the recording medium P is clamped is detected), the desired lateral registration correction and skew feeding correction are performed by the clamping roller 31, and the clamping roller is further based on the detection result (detection timing) of the paper detection sensor. The conveyance speed by 31 is varied. That is, the conveyance speed by the nipping roller 31 is set so that the timing at which the recording medium P is conveyed to the transfer unit 7 by the nipping roller 31 and the timing at which the image formed on the photosensitive drum 5 reaches the transfer unit 7 are matched. (The conveyance timing of the recording medium P conveyed toward the image forming unit is adjusted). Thus, the image can be transferred to a desired position on the recording medium P while the lateral registration correction and the skew feeding correction of the recording medium P are performed without stopping the conveyance of the recording medium P by the sandwiching roller 31.
Note that the clamping roller 31 does not cause distortion in the image transferred onto the recording medium P due to a difference in linear velocity between it and the photosensitive drum 5 immediately after the leading edge of the recording medium P reaches the image forming unit. Thus, the conveyance speed is varied (the conveyance speed is varied so that the linear velocity ratio with respect to the photosensitive drum 5 is 1).

The skew detection sensor 35 as the first detection means detects the amount of positional deviation (skew amount) in the oblique direction of the recording medium P conveyed in the conveyance path.
Specifically, with reference to FIG. 3, the skew detection sensor 35 is installed on the upstream side of the conveyance path with respect to the sandwiching roller 31 and on the downstream side of the conveyance path with respect to the third conveyance roller pair 44. Yes. The skew detection sensor 35 is two photosensors (consisting of a light emitting element such as an LED and a light receiving element such as a photodiode) installed at positions equidistant from the center position in the width direction. The skew amount β (skew amount) of the recording medium P is detected by detecting the deviation of the timing when the leading end of the recording medium passes. In the present embodiment, skew correction is performed while the recording medium P is sandwiched and conveyed by the sandwiching roller 31 based on the detection result of the skew detection sensor 35.
As a specific example, referring to FIG. 3, the recording medium P is only in the positive direction (the positive direction of the rotation direction) by an angle β with respect to the reference position indicated by the alternate long and short dash line (the normal position without skew). When the skew detection state is detected by the skew detection sensor 35, the control unit sets the positional deviation amount β as a correction amount, and the holding roller 31 (holding frame) while the recording medium P is held by the holding roller 31. 72) is rotated by an angle β in the reverse direction (the reverse direction of the rotation direction and the clockwise direction in FIG. 3).

Referring to FIG. 3, the CIS 36 as the second detection means is installed on the upstream side of the conveyance path with respect to the sandwiching roller 31 and on the downstream side of the conveyance path with respect to the third conveyance roller pair 44. . 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 (second 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. Then, based on the detection result of the CIS 36, the lateral registration correction by the sandwiching roller 31 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.

Then, based on the detection result of the CIS 36 (second detection means), the holding roller 31 (holding frame 72) is moved in the width direction while the recording medium P is held and conveyed by the holding roller 31, and is conveyed in the conveyance path. The positional deviation (lateral registration) in the width direction of the recording medium P to be recorded is corrected.
As a specific example, referring to FIG. 3, the recording medium P is positioned at one end side in the width direction (below the lower side in FIG. 3) with respect to the reference position indicated by the alternate long and short dash line (the normal position without any positional deviation in the width direction). When the CIS 36 detects that the position is shifted by the distance α, the control unit sets the position shift amount α as a correction amount, and the recording medium P is sandwiched and conveyed by the sandwiching roller 31. The roller 31 (holding frame 72) is moved by the distance α to the other end in the width direction (upward in FIG. 3).

Thus, in the present embodiment, the clamping roller 31 is based on the detection result of the skew detection sensor 35 (first detection means) while holding the recording medium P without stopping the conveyance of the recording medium P. In addition to correcting the positional displacement amount of the recording medium P in the oblique direction by rotating in the oblique direction, the recording medium P is moved in the width direction based on the detection result of the CIS 36 (second detecting means). This is to correct the positional deviation amount. That is, in the present embodiment, the skew amount of the recording medium P is detected by the skew detection sensor 35 in a state where the pinching roller 31 is rotated so as to be able to transport the recording medium P, and the recording medium P is detected based on the detection result. Lateral registration correction is performed, and then the amount of lateral registration deviation of the recording medium P is detected by the CIS 36, and the lateral registration correction of the recording medium P is performed based on the detection result.
As a result, the productivity of the apparatus can be significantly improved as compared with the case where the conveyance of the recording medium P is stopped and the skew feeding correction and the lateral registration correction are separately performed. Further, when skew correction or lateral registration correction is performed, there is no difference in linear velocity between a plurality of roller portions installed in the width direction in the pinching roller 31, so that the recording medium P having a low friction coefficient on thin paper or the surface. Even when the paper is passed, the recording medium P is not bent or slipped.

Hereinafter, an example of the operation of the transport apparatus 30 configured as described above will be described in detail with reference to FIGS. 9 and 10.
9 (A1) to (C1) and FIGS. 10 (A1) to (B1) are top views showing the operation of the conveying device 30 in the order shown in FIGS. 9 (A2) to (C2). FIGS. 10A2 to 10B2 are side views of the transfer device 30 corresponding to the operations of FIGS. 9A1 to 9C1 and 10A1 to 10B1, respectively.
First, as shown in FIGS. 9A1 and 9A2, the recording medium P fed from the paper feeding unit 12 is nipped and conveyed toward the position of the nipping roller 31 by the third conveying roller pair 44. (Conveyance in the direction of white arrow). At this time, the sandwiching roller 31 has a rotation direction position at a first reference position (a normal position corresponding to the recording medium P without skew), and a width direction position at a second reference position (horizontal). It is a normal position corresponding to the recording medium P with no registration position misalignment).
Then, when the recording medium P reaches the position of the CIS 36 (second detection means), the lateral registration positional displacement amount α of the recording medium P is detected by the CIS 36. Further, when the recording medium P reaches the position of the skew detection sensor 35 (first detection means), the skew detection sensor 35 detects the skew amount β of the recording medium P. Note that the amount of positional deviation detected directly by the CIS 36 is in a state where the recording medium P is skewed, so that the positional deviation is detected from the detection result detected by the skew detection sensor 35 and the position of the CIS 36. Based on the distance to the position of the row detection sensor 35, etc., the position registration amount α of the lateral registration when there is no skew is obtained by the calculation unit (control unit).

Thereafter, as shown in FIGS. 9B1 and 9B2, the sandwiching roller 31 is centered on the support shaft 73 in the same inclination direction in accordance with the skew amount β detected by the skew detection sensor 35 together with the holding frame 72. Is rotated from the first reference position by an angle β, and is shifted from the second reference position by the distance α in the same width direction in accordance with the positional deviation amount α detected by the CIS 36.
Then, as shown in FIGS. 9C1 and 9C2, immediately before the leading end of the recording medium P reaches the sandwiching roller 31, the rotational drive of the sandwiching roller 31 (rotation drive in the direction of the arrow in the figure) is started. Then, when the recording medium P is nipped and conveyed by the nipping roller 31, the third conveying roller pair 44 moves away from the conveying path so that the recording medium P is not nipped (indicated by the solid arrow). Note that the timing at which the leading end of the recording medium P reaches the pinching roller 31 is the timing at which the leading end of the recording medium P is detected by the skew detection sensor 35 or the CIS 36, the conveyance speed of the recording medium P, and the skew detection sensor 35. Alternatively, the calculation unit (control unit) can determine the distance from the position of the CIS 36 to the position of the pinching roller 31.

As shown in FIGS. 10A1 and 10A2, the sandwiching roller 31 supports the shaft so as to cancel the skew amount β detected by the skew detection sensor 35 while sandwiching and transporting the recording medium P. While rotating so as to return to the first reference position around 73, it moves in the width direction so as to return to the second reference position so as to cancel out the positional shift amount α detected by the CIS 35. In this way, the recording medium P is conveyed toward the transfer unit 7 (image forming unit) while performing skew feeding correction and lateral registration correction. At this time, the number of rotations of the nipping roller 31 (the conveyance speed of the recording medium P until reaching the transfer unit 7) is varied so as to match the timing on the image on the photosensitive drum 5.
Then, as shown in FIGS. 10B1 and 10B2, the recording medium P is conveyed toward the transfer unit 7 (image transfer unit), and the image is transferred to a desired position on the recording medium P. become. At this time, the nipping roller 31 is positioned at the first reference position and the second reference position in preparation for the skew correction and the lateral registration correction of the recording medium P to be conveyed next. Then, the nipping roller 31 that has been in the separated state is returned to the contact state (in the state of FIG. 7A2), assisting the conveyance of the recording medium P by the nipping roller 31, and then conveyed. In preparation for the conveyance operation of the recording medium P.

Here, as shown in FIG. 11, in the present embodiment, the support shaft 73 of the holding frame 72 (holding member) is substantially perpendicular to the rotational axis direction of the sandwiching roller 31 with respect to the two-stage spline coupling 65. It can also comprise so that it may be arranged in parallel. Specifically, in the example of FIG. 11, the support shaft 73 is disposed at a position directly below the two-stage spline coupling 65. In such a configuration, the deflection angle generated in the two-stage spline coupling 65 when the sandwiching roller 31 (holding frame 72) is rotated in accordance with the skew correction can be reduced. The rotational driving force can be transmitted from the first driving means to the pinching roller 31 (driving roller 31b) via the step spline coupling 65 with higher accuracy.
Further, as shown in FIG. 11, the sandwiching roller 31 in the present embodiment is not a pair of rollers having a plurality of roller portions divided in the width direction but a pair of rollers having a roller portion extending in the width direction. You can also.

As described above, in the present embodiment, the holding roller 31 is rotatably held, and can be moved in the surface direction to the base frame 71 (frame of the apparatus) via the free bearing 95 (relay support member). The support frame 73 (holding member) that is supported is provided with a support shaft 73 that fits into the guide portion 71 a formed on the base frame 71, and second drive means 63, 81 to 84 installed on the base frame 71, 98, by rotating the holding frame 72 around the support shaft 73 based on the detection result of the skew detection sensor 35 (first detection means) 98, the holding roller 72 and the holding roller 31 are rotated in an oblique direction. Based on the detection result of the CIS 36 (second detection means) by the third drive means 62, 74, 97 installed on the base frame 71, the support shaft 73 is guided by the guide portion 71. And it moves the holding rollers 31 in the width direction together with the holding frame 72 by moving along.
As a result, the skew correction and the lateral correction of the recording medium P can be performed without reducing the productivity of the transport apparatus 30 (image forming apparatus 1) and without increasing the size and cost of the transport apparatus 30 (image forming apparatus 1). Resist correction can be performed with high responsiveness and high accuracy.

In the present embodiment, the present invention is applied to the conveying device 30 that causes the sandwiching roller 31 that functions as a horizontal registration / skew correction roller to also function as a registration roller. However, the conveyance to which the present invention can be applied is also described. The apparatus is not limited to this, and even if it is a transport apparatus having another configuration, it is a matter of course for all the transport apparatuses as long as the transport apparatus performs skew feeding correction and lateral registration correction. The present invention can be applied. For example, the present invention can naturally be applied to a conveyance device in which a registration roller is installed on the downstream side of the sandwiching roller 31 that functions as a horizontal registration / skew correction roller.
In the present embodiment, the present invention is applied to the conveyance device 30 that performs skew correction and lateral registration correction of the transfer paper as the recording medium P on which an image is formed. Naturally, the present invention can also be applied to a conveyance device that performs skew correction and lateral registration correction.
In the present embodiment, the present invention is applied to the conveyance device 30 installed in the monochrome image forming apparatus 1, but 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 inkjet image forming apparatus or an offset printing machine) can be used as long as the transport device performs skew feeding correction and lateral registration correction. Of course, the present invention can also be applied to all the transport apparatuses.
Even in those cases, the same effects as in the present embodiment can be obtained.

In the present embodiment, the first driving means is configured to push the holding frame 72 (protrusion 72a) indirectly via the lever member 81 by the first cam 84, but directly by the first cam. Alternatively, the first drive means can be configured to push the holding frame.
In the present embodiment, the second driving means is configured to push the holding frame 72 (support shaft 73) directly by the second cam 74, but the holding frame is indirectly pushed by the second cam. The second drive means can also be configured to move.
In the present embodiment, the cam mechanisms are used as the second and third driving units, respectively. However, the second and third driving units are not limited to these, and for example, as the second and third driving units. A solenoid mechanism, a pinion rack mechanism, or the like can also be used.
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.

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

1 image forming apparatus (image forming apparatus main body),
30 transport device,
31 Nipping roller (horizontal registration / skew correction roller, registration roller),
31a driven roller,
31b Driving roller,
35 Skew detection sensor (first detection means),
36 CIS (second detection means),
51 alignment section,
61 1st motor (1st drive means),
62 third motor (third driving means),
63 second motor (second driving means),
65 2-stage spline coupling,
70 body frame (device frame),
71 Base frame (device frame),
71a guide part (hole part),
72 holding frame (holding member),
73 spindle,
74 second cam (third drive means),
75 cam follower,
76 Guide rollers (rollers),
81 lever member,
82 cam follower (first roller-shaped member),
83 action roller (second roller-shaped member),
84 first cam (second driving means),
91 second tension spring (second biasing member),
92 first tension spring (first biasing member),
95 Free bearing (relay support member),
P Recording medium (sheet).

JP-A-9-175694 Japanese Patent Laid-Open No. 10-67448

Claims (10)

A transport device for transporting a recording medium in a transport path,
First detection means for detecting the amount of positional deviation in the oblique direction of the recording medium conveyed in the conveyance path;
Second detection means for detecting the amount of positional deviation in the width direction of the recording medium conveyed in the conveyance path;
A nipping roller that is rotationally driven by the first driving means and conveys the recording medium in a nipped state;
A holding member that rotatably holds the clamping roller;
A relay support member that is installed in a frame of the apparatus and supports the holding member so as to be movable in either a width direction or an oblique direction with respect to the frame;
With
The holding member comprises a support shaft that fits into a guide portion formed to extend in the width direction in the frame;
Installed on the frame, the holding member is rotated about the support shaft based on the detection result of the first detection means, so that the holding roller and the holding roller can be rotated in an oblique direction. Second driving means,
The nipping roller is installed in the frame and configured to move the holding roller together with the holding member in the width direction by moving the support shaft along the guide portion based on a detection result of the second detection means. 3 driving means;
A conveying apparatus further comprising: The second drive means includes a first cam that directly or indirectly pushes the holding member biased in the forward direction of the diagonal direction by the first biasing member in the reverse direction of the diagonal direction,
The third driving means includes a second cam that pushes the holding member biased in the forward direction of the width direction by the second biasing member directly or indirectly in the opposite direction of the width direction. The transport apparatus according to claim 1, wherein A lever member that is rotatably held by the frame and includes a rotatable first roller-shaped member that contacts the first cam and a rotatable second roller-shaped member that contacts the holding member;
The transport apparatus according to claim 2, wherein the second driving unit is configured to push the holding member via the lever member.   4. The transport device according to claim 2, wherein each of the first cam and the second cam is formed such that a cam curve thereof is a constant velocity cam curve. 5.   The guide portion is a hole or groove having a substantially rectangular shape or a substantially elongated hole shape, and the support shaft is formed to fit into the hole or the groove via a roller-shaped member. The transport apparatus according to any one of claims 1 to 4.   6. The relay support member according to claim 1, wherein the relay support member is three or more free bearings disposed so as to support the holding member at three or more locations with respect to the frame. The conveying apparatus as described in.   The first driving means is installed on the frame and configured to transmit a driving force to the clamping roller via a two-stage spline coupling. The conveying apparatus as described in.   The conveying device according to claim 7, wherein the support shaft of the holding member is juxtaposed in a direction substantially perpendicular to a rotation axis direction of the clamping roller with respect to the two-stage spline coupling.   9. The conveying apparatus according to claim 1, wherein the clamping roller is a registration roller that conveys a recording medium toward the image forming unit at a timing.   An image forming apparatus comprising the transport device according to claim 1.

Images