JP2017193394A - Conveyance device and image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in which: when a conveyance object medium enters a nip part of a roller pair or the conveyance object medium is conveyed by the roller pair, inclination of the conveyance object medium may occur.SOLUTION: A conveyance device comprises a roller pair 31a, 31b which conveys a conveyance object medium by rotating in a state of being brought into pressure-contact with each other and holding the conveyance object medium. One roller 31b of the roller pair 31a, 31b includes: a drive shaft 32b which is rotationally driven; a central roller part 33b which is provided at the center in the axial direction of the drive shaft 32b so as not to rotate with respect to the drive shaft 32b; and end roller parts 34b which are rotatably provided with respect to the drive shaft 32b on both end sides in the axial direction of the drive shaft 32b with respect to the central roller part 33b. The end roller parts 34b rotate following the rotation of the drive shaft 32b with the frictional force generated between the end roller parts 34b and the drive shaft 32b in a state of being brought into pressure-contact with the other roller 31a of the roller pair 31a, 31b.SELECTED DRAWING: Figure 15

Description

  The present invention relates to a conveyance device that conveys a medium to be conveyed, and an image forming apparatus including the conveyance device.

  2. Description of the Related Art Image forming apparatuses such as copying machines and printers are provided with a transport device that sandwiches and transports recording paper or the like as a transported medium with a pair of rotating rollers.

  By the way, when the transported medium is transported, the transported medium may be inclined with respect to the transport direction or may be laterally shifted in a direction perpendicular to the transport direction. Conventionally, in order to correct such inclination and lateral deviation, a conveyance device has been proposed in which a medium to be conveyed is rotated in a direction opposite to the inclination direction or moved in a direction opposite to the lateral deviation direction and returned to the correct position. .

  For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2014-88263), based on the amount of inclination or lateral displacement of the recording medium detected by the detecting means, the holding roller is rotated or axially held with the recording medium held therebetween. A conveyance device that corrects inclination and lateral deviation by moving the image has been proposed.

  As in the transport apparatus described in Patent Document 1, the tilt and lateral deviation of the recording medium can be corrected by rotating or axially moving the clamping roller based on the detected inclination amount and lateral deviation amount. is there. However, when the recording medium enters the nip portion of the sandwiching roller or when the recording medium is conveyed by the sandwiching roller, a new tilt of the recording medium may occur. In this case, even if the nipping roller is rotated or moved in the axial direction based on the detected tilt amount or lateral shift amount, the newly generated tilt is not corrected, so that the correction accuracy decreases.

  In order to solve the above-described problem, the present invention provides a transport device including a pair of rollers that are in pressure contact with each other and transport the medium to be transported by rotating in a state of sandwiching the medium to be transported. The roller includes a drive shaft that is rotationally driven, a central roller portion that is provided on an axially central side of the drive shaft so as not to rotate with respect to the drive shaft, and both axial ends of the drive shaft that are closer to the central roller portion An end roller portion provided rotatably on the drive shaft with respect to the drive shaft, wherein the end roller portion is in pressure contact with the other roller of the roller pair and the end roller portion It rotates with the rotation of the said drive shaft by the frictional force produced between drive shafts, It is characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, when a to-be-conveyed medium approachs the nip part of a roller pair, or when a to-be-conveyed medium is conveyed by a roller pair, the inclination of the to-be-conveyed medium can be suppressed. Thereby, the positional accuracy of the medium to be transported can be improved and the medium to be transported can be transported.

1 is a schematic diagram illustrating an overall configuration of an image forming apparatus according to an embodiment of the present invention. It is the schematic which shows the whole structure of a conveying apparatus. It is a top view of a conveying apparatus. It is a front view of a conveying apparatus. It is a top view which shows the drive mechanism of a conveying apparatus. It is a front view which shows the structure of the relay support member of a conveying apparatus. It is a figure which shows the movement operation | movement to the width direction of a holding frame. It is a top view which shows rotation operation | movement of a holding frame. It is the schematic which shows the structure of a two-stage spline coupling. It is a figure which shows the structure of an attachment member, Comprising: (a) is a cross-sectional top view, (b) is a side view of one clamping part, (c) is a side view of the other clamping part. It is a cross-sectional top view which shows the structure of another attachment member. It is the schematic which shows the correction | amendment operation | movement of a conveying apparatus. It is the schematic which shows the correction | amendment operation | movement of a conveying apparatus. FIG. 6 is a diagram illustrating a state in which one side end portion of a recording medium is conveyed to a pair of nipping rollers in a state where the one side end portion is positioned below the other side end portion. It is a front view which shows the structure of a clamping roller pair and its peripheral part. (A) is a side view which shows the structure of a center roller part, (b) is a side view which shows the structure of an end roller part. It is a figure which shows arrangement | positioning of a conveyance guide pair. It is a front view which shows the structure of the clamping roller pair which concerns on other embodiment of this invention, and its periphery part. It is a top view of the lower clamping roller which concerns on another embodiment of this invention. It is a side view of a clamping roller pair. It is the schematic which shows the conveyance operation of a conveying apparatus. It is a front view of the conveying apparatus concerning another embodiment of the present invention.

  Hereinafter, the present invention will be described with reference to the accompanying drawings. In the drawings for explaining the present invention, components such as members and components having the same function or shape are denoted by the same reference numerals as much as possible, and once described, the description will be given. Omitted.

First, the overall configuration and operation of the image forming apparatus will be described with reference to FIG.
In FIG. 1, reference numeral 1 denotes a copying machine as an image forming apparatus, 2 denotes a document reading unit that optically reads image information of a document D, and 3 denotes 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 (sheet) P 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 recording medium P Nip roller pair which serves the positional deviation as a correction roller for conveying while correcting, 15 is a timing roller for conveying the recording medium P to the transfer unit 7 at a predetermined timing.

With reference to FIG. 1, an operation during normal image formation in the copying machine 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 electrical signal and then transmitted to the exposure unit 3. Then, exposure light (laser light) L 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 clockwise 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 pair of clamping rollers 31 and the pair of timing rollers 15 in the transfer unit 7 as an image forming unit.

Further, the recording medium P conveyed to the transfer unit 7 is conveyed as follows.
First, as shown in FIG. 2, one of the plurality of paper feeding units 12 to 14 of the copying machine 1 is automatically or manually selected. For example, when the paper feed unit 12 provided in the copier 1 is selected, the uppermost sheet of the recording medium P stored in the paper feed unit 12 is fed by the paper feed roller 41 to the first transport roller. The pair 42 and the second transport roller pair 43 are fed toward the curved transport path where the pair is installed.

  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 copying machine 1 merge), and then the third medium. It passes through the straight conveyance path in which the conveying roller pair 44 and the aligning unit 51 are installed, and reaches the position of the nipping roller pair 31 constituting the aligning unit 51. Then, the pair of clamping rollers 31 constituting the aligning unit 51 performs tilt correction and lateral shift correction of the recording medium P, and further, a timing roller pair for aligning with an image formed on the photosensitive drum 5. 15 is conveyed toward the transfer unit 7 at the same timing.

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 is fixed is delivered from between the fixing roller 21 and the pressure roller 22 (nip portion), and then discharged from the copying machine 1.
Thus, a series of image forming processes is completed.

  Here, in the present embodiment, there are a conveyance path from the paper feeding unit 12 installed inside the copying machine 1 and a conveyance path from the two paper feeding units 13 and 14 installed outside the copying machine 1. As a transport path from the joining section X to the transfer section 7, a straight transport path formed in a substantially linear shape along the transport direction of the recording medium P is provided. This linear transport path is formed by a linear transport guide plate or the like installed so as to sandwich the front and back surfaces of the recording medium P to be transported, and the third transport roller pair 44, CIS (lateral deviation detection means) along the transport direction. ) 36, a skew detection sensor (tilt detection means) 35, a pair of clamping rollers 31, and a pair of timing rollers 15 are provided.

  Including the third conveying roller pair 44, the sandwiching roller pair 31, and the timing roller pair 15, the conveying roller pairs 42 to 44 (including conveying roller pairs not denoted by reference numerals) installed in the conveying device 30 are all included. Also, this is a roller pair composed of a driving roller that is rotationally driven by a driving mechanism and a driven roller that is driven to rotate by frictional resistance with the driving roller. The recording medium P is conveyed while being sandwiched between these conveying roller pairs. Further, the pair of nipping rollers 31 serves as an alignment unit 51 for performing an alignment operation of inclination correction for correcting the inclination of the recording medium P with respect to the conveyance direction and lateral deviation correction for correcting a positional deviation in the width direction orthogonal to the conveyance direction. Also works.

  Specifically, as shown in FIG. 3 when the conveying device 30 is viewed from above, the sandwiching roller pair 31 has an inclination direction of the recording medium P around a support shaft 73 serving as a rotation fulcrum and a direction opposite thereto (FIG. 3). And is configured to be movable in the width direction of the recording medium P (in the direction of the broken line arrow S in FIG. 3). The clamping roller pair 31 rotates around the support shaft 73 based on the detection result of the skew detection sensor 35 to correct the inclination of the recording medium P, or the width of the recording medium P based on the detection result of the CIS 36. The lateral shift of the recording medium P is corrected by moving in the direction.

  The skew detection sensor 35 detects a positional deviation amount (skew amount) in the tilt direction of the recording medium P conveyed in the conveyance path. Specifically, as illustrated in FIG. 3, the skew detection sensor 35 is disposed upstream of the conveyance path with respect to the sandwiching roller pair 31 and downstream of the conveyance path with respect to the third conveyance roller pair 44. ing. The skew detection sensor 35 is two photosensors (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 inclination amount (skew amount) β of the recording medium P is detected by detecting the deviation of the passing timing. In the present embodiment, based on the detection result of the skew detection sensor 35, tilt correction is performed while the recording medium P is sandwiched and conveyed by the pair of sandwiching rollers 31.

  For example, as shown in FIG. 3, the recording medium P is in the positive direction (in the rotational direction) with respect to the reference position Y indicated by the alternate long and short dash line (the reference position at the end in the width direction of the recording medium P conveyed without tilting or lateral displacement). When the skew detecting sensor 35 detects that the state is tilted in the positive direction) by the angle β, the control unit sets the tilt amount β as a correction amount and sandwiches the recording medium P by the sandwiching roller pair 31. The roller pair 31 is rotated by an angle β in the reverse direction (the reverse direction of the rotation direction and clockwise in FIG. 3).

  On the other hand, the CIS 36 includes a plurality of photosensors (a light emitting element such as an LED, a light receiving element such as a photodiode, and an imaging lens) arranged in parallel in the width direction. The shift amount in the width direction is detected by detecting the position of the side end portion Pa (edge portion). Similar to the skew detection sensor 35, the CIS 36 is installed on the upstream side of the conveyance path with respect to the sandwiching roller pair 31 and on the downstream side of the conveyance path with respect to the third conveyance roller pair 44. Then, based on the detection result of the CIS 36, lateral deviation correction by the clamping roller pair 31 is performed.

  For example, as shown in FIG. 3, the recording medium P is displaced by a distance α on one end side in the width direction (downward in FIG. 3) with respect to the reference position Y indicated by the alternate long and short dash line. When detected by the CIS 36, the control unit sets the positional deviation amount α as a correction amount, and the clamping roller pair 31 is moved in the other end in the width direction (in FIG. 3) while the recording medium P is clamped and conveyed by the clamping roller pair 31. Move upward (distance) by a distance α.

Next, based on FIGS. 4-11, the structure of the conveying apparatus 30 is demonstrated in detail.
As shown in FIG. 4, the pair of sandwiching rollers 31 includes a driving roller 31b to which a driving force from a motor 61 as a sandwiching roller driving unit is applied, and a driven roller 31a that is driven to rotate together with the driving roller 31b. These rollers 31a and 31b are held rotatably around a roller axis by a holding frame 72 as a holding member.

  The holding frame 72 is supported by a base frame 71 as a fixed support fixed to a main body frame 70 constituting a frame on the apparatus main body side, and a movable frame 81 as a movable support provided on the base frame 71. Yes.

  As shown in FIG. 5, the holding frame 72 is installed on the upper surface of the base frame 71 via a free bearing (ball transfer) 95 as a relay support member. As a result, the holding frame 72 is configured to be movable relative to the base frame 71 in the front / rear / left / right (substantially horizontal) direction along the upper surface thereof.

  As shown in FIG. 6, the free bearing 95 is a known bearing in which a sphere (steel ball) 95a is rotatably mounted in a recess of a pedestal 95b, and the top of the sphere 95a makes point contact with the bottom surface of the holding frame 72. To do. In the present embodiment, four free bearings 95 are arranged at the four corners on the bottom surface of the holding frame 72 so as to support the holding frame 72 at four places, but there are three places where the holding frame 72 is supported by the free bearing 95. That is all you need.

  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, the friction load caused thereby is extremely reduced. Can be small. For this reason, lateral shift correction and inclination correction described later can be performed at high speed and with high accuracy.

  As shown in FIG. 4, a support shaft 73 is provided on the bottom surface of the holding frame 72 so as to extend downward. A lower end portion of the support shaft 73 is inserted into a width direction guide portion 71 a formed on the base frame 71. The width direction guide portion 71a is a hole formed so as to extend substantially linearly in the width direction of the recording medium P (the direction of the broken line arrow S in FIG. 5). In the present embodiment, the width direction guide portion 71a is configured by a hole portion that penetrates the upper surface portion of the base frame 71, but may be a groove portion that has a bottom portion without penetrating. Further, a guide roller 79 is rotatably provided at the lower end portion of the support shaft 73, and the guide roller 79 is inserted into the guide portion 71a.

  The support shaft 73 and the guide roller 79 are movable in the extending direction of the width direction guide portion 71a (the width direction S of the recording medium P). As the support shaft 73 moves along the width direction guide portion 71 a, the holding frame 72 can reciprocate in the width direction S of the recording medium P with respect to the base frame 71. The holding frame 72 is also configured to rotate with respect to the base frame 71 about the support shaft 73 (in the direction of the broken line arrow W in FIG. 5).

  The movable frame 81 is configured to be rotatable on the upper surface of the base frame 71 (in the direction of the broken line arrow Z in FIG. 5) around the rotation shaft 63 a of the motor 63 installed on the base frame 71. The movable frame 81 and the holding frame 72 are interlocked and connected via a connecting shaft 74. Specifically, the connecting shaft 74 is provided so as to extend downward from the holding frame 72, and a lower end portion thereof is substantially straight in a radial direction (direction of a broken line arrow R in FIG. 5) intersecting the rotation direction of the movable frame 81. It is inserted in the radial direction guide part 81a formed so that it may extend in a shape. In the present embodiment, the radial guide portion 81a is configured by a hole portion that penetrates the movable frame 81, but may be a groove portion that has a bottom portion without penetrating. Further, similarly to the support shaft 73, a guide roller 82 is rotatably provided at the lower end portion of the connecting shaft 74, and the guide roller 82 is inserted into the radial guide portion 81a.

  Since the holding frame 72 and the movable frame 81 are connected as described above, both the frames 72 and 81 are interlocked with each other. For example, in FIG. 7, when the support shaft 73 is moved in the right direction in the drawing along the width direction guide portion 71a and the holding frame 72 is moved in the same direction, the connecting shaft 74 is also moved in the right direction in the drawing. Moving. As the connecting shaft 74 moves, the movable frame 81 is interlocked so as to rotate clockwise around the rotating shaft 63a. On the other hand, as shown in FIG. 8, when the connecting shaft 74 is moved upward along the radial guide portion 81a without moving the support shaft 73, the movable frame 81 is centered on the rotating shaft 63a. While rotating clockwise in the figure, the holding frame 72 is interlocked so as to rotate clockwise around the support shaft 73 in the figure. 7 and 8, when the support shaft 73 or the connecting shaft 74 is moved in the opposite direction, the moving direction or the rotating direction of the frames 72 and 81 is opposite.

  Here, as shown in FIG. 4, the driving roller 31 b of the clamping roller pair 31 and the motor 61 that rotationally drives the driving roller 31 b are connected to each other via transmission members of gear trains 66 and 67. Therefore, when the holding frame 72 moves or rotates in the width direction as described above, the relative position between the drive roller 31b and the motor 61 changes. Therefore, in the present embodiment, the two-stage spline cup is added to the gear trains 66 and 67 so that the drive transmission from the motor 61 to the drive roller 31b can be satisfactorily performed even if the holding frame 72 moves or rotates in the width direction. It is connected via a ring 65.

  As shown in FIG. 9, 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 65 a is an external gear, and is provided on the rotation shaft 67 a of one gear 67 of the gear trains 66 and 67. The second spline gear 65 b is an external gear, and is provided on the shaft portion of the drive roller 31 b of the clamping roller pair 31. The intermediate spline gear 65c is an internal gear, and extends in the width direction of the recording medium P so as to mesh with the two spline gears 65a and 65b even if the holding frame 72 moves in the width direction of the recording medium P. ing. 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 holding frame 72 rotates. The guide ring 65d is a substantially annular stopper member, and prevents 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. 65c is provided at both ends in the width direction.

  By using such a two-stage spline coupling 65, even if the holding frame 72 rotates or moves in the width direction, the driving force of the motor 61 fixed to the frames 69 to 71 of the apparatus main body is used as a pair of clamping rollers. It is reliably and accurately transmitted to the drive roller 31b of 31. Thereby, the clamping roller pair 31 is driven to rotate favorably.

  As shown in FIG. 4, a rotary encoder 96 as a rotation detecting means for detecting the amount of rotation of the drive roller 31b is provided at the end of the drive roller 31b opposite to the side to which the rotational driving force is applied. It has been. The sandwiching roller pair 31 feeds back the detection result of the rotary encoder 96, and the rotation speed and rotation timing are controlled with high accuracy.

  Further, the apparatus body (main body frame 70, base frame 71, movable frame 81) of the conveying device 30 is provided with a pair of sandwiching rollers 31 together with the holding frame 72 based on the detection result of the CIS 36 as the lateral deviation detection means. And the holding belt 72 together with the holding belt 72 based on the detection result of the first belt drive mechanism 75 that reciprocates in the width direction and the skew detection sensor 35 as the tilt detection means. And a second belt drive mechanism 76 that rotates in the opposite direction.

  As shown in FIG. 4, the first belt drive mechanism 75 includes an endless belt 77 stretched by a drive pulley 83 and a tension pulley 84 as a rotation support, and a belt 77 that rotates the drive pulley 83 to rotate. The motor 62 or the like as belt driving means for rotating the belt. The motor 62 is provided on the base frame 71, and a drive pulley 83 is attached to the upper end portion of the rotating shaft 62 a of the motor 62. On the other hand, a rotary encoder 57 as a rotation detecting means for detecting the amount of rotation of the motor 62 is attached to the opposite end (lower end) of the rotation shaft 62a of the motor 62.

  As shown in FIG. 5, the tension pulley 84 is attached to a support portion 87 provided on the base frame 71 via a tension spring 89 as an urging member. The belt 77 is held by the tension spring 89 in a state where a predetermined tension is applied.

  A support shaft 73 that is a rotation fulcrum of the holding frame 72 is integrally attached to the belt 77. Specifically, a support shaft 73 is attached to a linear portion of a belt 77 stretched between the drive pulley 83 and the tension pulley 84 via an attachment member 91.

FIG. 10A is a cross-sectional view of the attachment member 91 of the first belt drive mechanism 75 as viewed from above.
As shown in FIG. 10A, the attachment member 91 has a pair of clamping portions 91a and 91b for holding the belt 77 with the belt 77 interposed therebetween. FIG. 10B is a side view of the upper holding portion 91a in FIG. 10A, and FIG. 10C is a side view of the lower holding portion 91b in FIG.

  A plurality of fitting grooves 91c into which the convex portions 77a arranged in the circumferential direction (moving direction) of the belt 77 are fitted are formed in the upper clamping portion 91a in FIG. In the present embodiment, the fitting groove 91c is configured by a hole that penetrates the clamping portion 91a, but may be a groove having a bottom that does not penetrate. On the other hand, the lower holding portion 91b in FIG. 10A is provided with a cylindrical shaft holding portion 91e having an insertion hole 91d into which the support shaft 73 is rotatably inserted.

  The pair of sandwiching portions 91 a and 91 b are fixed to the belt 77 by being connected by a fixing tool such as a screw in a state where the belt 77 is sandwiched. Further, when the belt 77 is sandwiched between the pair of sandwiching portions 91a and 91b, the convex portion 77a of the belt 77 is fitted into the fitting groove 91c. Then, the support shaft 73 is integrally attached to the belt 77 by inserting the support shaft 73 into the insertion hole 91d of the shaft holding portion 91e.

  As shown in FIG. 10A, an encoder sensor 53 is attached to the holding portion 91a in which the fitting groove 91c is formed. The encoder sensor 53 is a transmissive photosensor or the like, and reads a predetermined pattern of an encoder scale 54 (see FIG. 5) provided on the base frame 71. These encoder sensor 53 and encoder scale 54 constitute a linear encoder as belt movement detecting means for detecting movement of the belt 77.

Next, the configuration of the second belt drive mechanism 76 will be described.
As shown in FIGS. 4 and 5, the second belt drive mechanism 76 is an endless belt stretched by a drive pulley 85 and a tension pulley 86 as a rotation support, similarly to the first belt drive mechanism 75. 78 and a motor 63 as belt driving means for rotating the driving pulley 85 to move the belt 78 around. However, unlike the belt 77 of the first belt drive mechanism 75, the belt 78 is provided on the movable frame 81 and is configured to be rotatable integrally with the movable frame 81. Here, when the movable frame 81 rotates around the rotating shaft 63a of the motor 63, the tension pulley 86 rotates around the driving pulley 85 attached to the upper end portion of the rotating shaft 63a of the motor 63 as the rotating shaft, thereby the belt 78. Rotate together.

  The tension pulley 86 is attached to a support portion 88 provided on the movable frame 81 via a tension spring 90 as an urging member. As a result, the belt 78 is held in a state where a predetermined tension is applied, like the belt 77 of the first belt drive mechanism 75. A rotary encoder 58 is attached to the lower end of the motor 63 as rotation detecting means for detecting the amount of rotation.

  A connecting shaft 74 that connects the holding frame 72 and the movable frame 81 is integrally attached to the belt 78. Specifically, the connecting shaft 74 is attached to the linear portion of the belt 78 stretched between the drive pulley 85 and the tension pulley 86 via the attachment member 92.

FIG. 11 is a cross-sectional view of the attachment member 92 of the second belt drive mechanism 76 as viewed from above.
The mounting member 92 has basically the same configuration as the mounting member 91 shown in FIG. As shown in FIG. 11, the attachment member 92 has a pair of clamping parts 92a and 92b. A plurality of fitting grooves 92c into which convex portions 78a arranged in the circumferential direction (moving direction) of the belt 78 are fitted are formed in one clamping portion 92a, and the connecting shaft 74 is rotatable in the other clamping portion 92b. A cylindrical shaft holding portion 92e in which an insertion hole 92d to be inserted is formed is provided. Here, the connecting shaft 74 is inserted through the bearing 93 into the shaft holding portion 92e. As in the case of the mounting member 91, the fitting groove 92c formed in the one sandwiching portion 92a may be a hole portion that penetrates the sandwiching portion 92a or a groove portion that has a bottom portion that does not penetrate.

  Similarly to the above, these sandwiching portions 92a and 92b also sandwich the belt 78 so that the convex portion 78a of the belt 78 fits into the fitting groove 92c, and are connected to each other by a fixing tool such as a screw. It is fixed against. Then, the connecting shaft 74 is integrally attached to the belt 78 by inserting the connecting shaft 74 into the insertion hole 92 d of the shaft holding portion 92 e through the bearing 93.

  The second belt drive mechanism 76 is also provided with a linear encoder as belt movement detection means for detecting the movement of the belt 78, as with the first belt drive mechanism 75. The linear encoder includes an encoder sensor 55 attached to the attachment member 92 and an encoder scale 56 provided on the movable frame 81. As shown in FIG. 11, here, the encoder sensor 55 is attached to the holding portion 92b provided with the shaft holding portion 92e. However, depending on the component layout, the encoder sensor 55 is attached to the holding portion 92a formed with the fitting groove 92c. May be.

Here, the operation of the holding frame 72 by the first belt driving mechanism 75 and the second belt driving mechanism 76 will be described with reference to FIGS.
First, when the holding frame 72 is moved in the width direction of the recording medium P, the belt 77 is moved around by driving the motor 62 of the first belt drive mechanism 75, and the support shaft 73 is moved to the width direction guide portion 71a. Move along. For example, in FIG. 7, when the support shaft 73 is moved in the right direction in the drawing, the holding frame 72 is also moved in the right direction in the drawing, that is, in the width direction of the recording medium P. Further, when the motor 62 is rotated in the reverse direction, the support shaft 73 moves in the left direction in the figure, and the holding frame 72 also moves in the left direction in the figure.

  Next, when rotating the holding frame 72, the belt 63 is moved around by driving the motor 63 of the second belt drive mechanism 76, and the connecting shaft 74 is moved along the radial guide portion 81a. For example, in FIG. 8, when the connecting shaft 74 is moved upward in the figure, the holding frame 72 rotates in the clockwise direction in the figure around the support shaft 73. On the other hand, when the motor 63 is rotated in the reverse direction, the connecting shaft 74 is moved downward in the figure, and the holding frame 72 is rotated counterclockwise in the figure.

Hereinafter, based on FIG.12 and FIG.13, an example of operation | movement of the conveying apparatus 30 comprised as mentioned above is demonstrated.
12 (a1) to (c1) and FIGS. 13 (a1) to (b1) are plan views showing the operation of the conveying device 30 in the order shown in FIGS. 12 (a2) to (c2). FIGS. 13 (a2) to (b2) are side views of the transfer device 30 corresponding to the operations of FIGS. 12 (a1) to (c1) and FIGS. 13 (a1) to (b1), respectively.

  First, as shown in FIGS. 12A1 and 12A2, the recording medium P fed from one of the paper feeding units is nipped toward the nipping roller pair 31 by the third conveying roller pair 44.・ Conveyed. The white arrow direction in the figure is the conveyance direction of the recording medium P. At this time, the nipping roller pair 31 has a rotation direction position at a first reference position (a normal position corresponding to the recording medium P without inclination), and a width direction position at a second reference position (a recording medium without lateral deviation). A normal position corresponding to P). In the present embodiment, the support shaft 73 that serves as the rotation fulcrum of the holding frame 72 that holds the sandwiching roller pair 31 is located at a position corresponding to the reference position Y in the width direction end of the recording medium P that is conveyed without being inclined or laterally displaced. Has been placed.

  When the recording medium P reaches the position of the CIS 36 as the lateral deviation detecting means, the lateral deviation amount (position deviation amount in the width direction) 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 as the tilt detection means, the skew detection sensor 35 detects the tilt amount (skew amount) β of the recording medium P. Note that the lateral deviation amount directly detected by the CIS 36 is in a state where the recording medium P is tilted, and therefore, the skew detection is detected from the detection result detected by the skew detection sensor 35 and the position of the CIS 36 thereafter. Based on the distance to the position of the sensor 35 and the like, the amount of lateral deviation when there is no inclination is obtained by the calculation unit (control unit).

  Then, based on the detection results of the skew detection sensor 35 and the CIS 36, the holding frame 72 is moved and rotated in the width direction, and as shown in FIGS. The recording medium P is rotated and moved in the width direction in accordance with the inclination and lateral deviation of the recording medium P. That is, the clamping roller pair 31 is rotated from the first reference position by the angle β around the support shaft 73 in the same inclination direction according to the detected inclination amount β, and the same according to the detected displacement amount α. It is moved in the width direction from the second reference position by a distance α in the width direction. Further, the pinching roller pair 31 starts to be rotated immediately before the leading end of the recording medium P reaches the pinching roller pair 31.

  Then, as shown in FIGS. 12C1 and 12C2, when the leading end portion of the recording medium P reaches the sandwiching roller pair 31, and the recording medium P is sandwiched and transported by the sandwiching roller pair 31, the third transport roller. The pair 44 moves away in a direction in which the conveyance path is opened and the recording medium P is not pinched. Note that the timing at which the leading edge of the recording medium P reaches the clamping roller pair 31 is the timing at which the leading edge 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. The calculation unit (control unit) can determine the distance from the position of 35 or CIS 36 to the position of the sandwiching roller pair 31.

  Then, as shown in FIGS. 13A1 and 13A2, the sandwiching roller pair 31 supports the tilt amount β detected by the skew detection sensor 35 while offsetting and transporting the recording medium P. The shaft 73 rotates around the shaft 73 so as to return to the first reference position, and moves in the width direction so as to return to the second reference position so as to cancel out the lateral shift amount α detected by the CIS 36. In this way, the recording medium P is conveyed toward the timing roller pair 15 while the inclination correction and the lateral deviation correction are performed. Then, as shown in FIGS. 13B1 and 13B2, the recording medium P is further conveyed to the downstream side (transfer unit 7) by the timing roller pair 15 and the sandwiching roller pair 31. Further, the third conveying roller pair 44 that has been in the separated state is returned to the abutting state to prepare for the conveying operation of the recording medium P to be conveyed next.

  Thus, in the present embodiment, the pair of clamping rollers 31 rotates in the tilt direction based on the detection result of the skew detection sensor 35 while holding the recording medium P without stopping the conveyance of the recording medium P. Thus, the positional deviation amount of the recording medium P in the tilt direction is corrected, and the positional deviation amount of the recording medium P in the width direction is corrected by moving in the width direction based on the detection result of the CIS 36. 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 inclination correction or the lateral deviation correction is performed separately.

  Moreover, in the configuration of the present embodiment, the first belt driving mechanism 75 and the second belt driving mechanism 76 having the heavy motors 62 and 63 and the motor 61 for driving the pair of clamping rollers 31 are provided on the apparatus main body side. Since these are not provided on the holding frame 72, the structure installed on the holding frame 72 can be reduced in weight. As a result, it is easy to move the holding frame 72 at high speed and with high accuracy, and it is possible to correct the tilt and lateral deviation of the recording medium P at high speed and with high accuracy. In addition, a relatively small output motor (drive source) can be used to drive the holding frame 72, and the apparatus can be reduced in size and weight.

  In the present embodiment, the support shaft 73 or the connecting shaft 74 is attached to the belts 77 and 78 of the first belt drive mechanism 75 and the second belt drive mechanism 76 so that they are moved. There are few gaps between the components constituting the drive mechanism, and the motor drive response is excellent.

  Further, in the present embodiment, the motors 62 and 63 are affected by the effects of a gap between components, tension fluctuation and expansion / contraction of the belts 77 and 78, frictional resistance between the recording medium P and the conveyance guide, or driving frictional resistance of the holding frame 72. The rotary encoders 57 and 58 that detect the rotation amount of the motors 62 and 63 and the linear encoder that detects the movement amount of the belts 77 and 78 even if an error occurs between the rotation amount of the belts 77 and 78. The error can be grasped based on the detection results of the encoder sensors 53 and 55 and the encoder scales 54 and 56). Then, by adjusting the rotation amounts of the motors 62 and 63 based on the grasped error, it is possible to perform more accurate inclination correction and lateral deviation correction.

  Further, in this embodiment, the pair of clamping rollers 31 and the motor 61 are connected using the two-stage spline coupling 65, so that the pair of clamping rollers 31 rotates or slides together with the holding frame 72. Even in this case, the connection state between the two can be maintained satisfactorily, and the drive can be reliably transmitted to the pair of clamping rollers 31.

  By the way, conventionally, when a recording medium is transported by the transport apparatus as described above, there is a case where the positional deviation of the recording medium cannot be corrected with high accuracy. As a result of intensive studies on the cause, the present inventor has found the following.

  First, when the recording medium enters the nip portion of the pair of sandwiching rollers or when the recording medium is transported while being sandwiched by the pair of sandwiching rollers, a new tilt of the recording medium may occur, which causes high accuracy. It became clear that it was impossible to correct. That is, if a new tilt occurs when the recording medium enters the nip portion or during nipping and conveying, even if correction is performed based on the previously detected tilt amount, the newly generated tilt is not corrected. The accuracy of correction decreases.

  The inclination that occurs when the recording medium enters the nip portion is such that one end side in the width direction of the recording medium comes into contact with the surface of the clamping roller before the other end side, or one end side precedes the other end side. And it enters the nip part. For example, as shown in FIG. 14, when the left end Pa1 (front side in the figure) of the recording medium P is positioned below the right end Pa2 (back side in the figure), the left end Pa1 is Prior to the right end Pa2, it contacts the lower clamping roller 31b. At this time, since the contact force with the pinching roller 31b acts only on the left end Pa1, an inclination occurs. Further, the timing at which the leading end portion of the recording medium P enters the nip portion of the sandwiching roller pair 31a, 31b varies depending on the parallelism of the leading end portion of the recording medium P with respect to the axis of the sandwiching roller pair 31a, 31b. For example, when the left end Pa1 of the recording medium P enters the nip portion of the sandwiching roller pair 31a, 31b ahead of the right end Pa2, the conveyance force by the sandwiching roller pair 31a, 31b is applied only to the left end Pa1. Or a contact force due to contact with the pair of sandwiching rollers 31a and 31b acts to cause inclination.

  The inclination of the recording medium that occurs during nipping and conveyance is caused by a deviation in conveying force due to a roller diameter deviation, a rubber hardness deviation, a pressure deviation between the rollers, and the like in the axial direction of the nipping roller. For example, when the pressing force of the pressure spring that presses the sandwiching rollers is strong on one side in the axial direction, the transport force increases on the strong pressurizing side, so that the recording medium is tilted during the sandwiching transport.

  As a method of correcting the inclination of the recording medium when entering the nip portion or during nipping and conveying as described above, for example, after the recording medium is nipped by the pair of nipping rollers, that is, when the nip portion enters or is nipped and conveyed. Then, a method of detecting the tilt amount of the recording medium and correcting the tilt based on the detection result can be considered. However, a certain amount of time is required until the correction operation (rotation operation in the tilt direction) of the pair of sandwiching rollers is completed after the tilt amount is detected. For this reason, when the method of detecting the tilt after the recording medium is sandwiched by the pair of sandwiching rollers is adopted, the pair of sandwiching rollers is aligned in the tilt direction within a short time while the recording medium is conveyed by the pair of sandwiching rollers (during the sandwiching). It is necessary to reversely rotate, and the time constraint becomes severe. In particular, when a recording medium having a short length in the transport direction is transported, it is necessary to take a measure of slowing the transport speed in order to keep the correction operation in time, and it is considered that rapid transport cannot be performed.

  Therefore, in the present embodiment, the following measures are taken in order to suppress the inclination of the recording medium when entering the nip portion or during nipping and conveying while maintaining the conveying speed.

FIG. 15 is a front view showing the configuration of the pair of clamping rollers 31a and 31b and their peripheral portions according to the present embodiment.
As shown in FIG. 15, in this embodiment, the pair of sandwiching rollers 31a and 31b are formed by center roller portions 33a and 33b and center roller portions 33a and 33b provided on the center side in the axial direction of the roller shafts 32a and 32b, respectively. Also have end roller portions 34a and 34b provided on both axial ends of the roller shafts 32a and 32b. The upper clamping roller 31a is pressed against the lower clamping roller 31b by a pressure spring 40 as a pressure member. The pressure springs 40 are arranged symmetrically with respect to the center in the axial direction of the upper clamping roller 31a, and are provided on the roller shaft 32a between the central roller portion 33a of the upper clamping roller 31a and each end roller portion 34a. The clamping roller 31a is pressurized via the bearing 50. The roller shaft 32a may be directly pressed by the pressure spring 40 without using the bearing 50.

16A is a side view showing the configuration of the central roller portions 33a and 33b, and FIG. 16B is a side view showing the configuration of the end roller portions 34a and 34b.
The center roller portion 33a and the end roller portion 34a of the upper clamping roller 31a are both provided to be rotatable with respect to the roller shaft 32a. Specifically, as shown in FIG. 16A, the upper central roller portion 33 a is provided on the outer peripheral surface of the rolling bearing 10 and the rolling bearing 101 provided on the outer peripheral surface of the metal roller shaft 32 a. The resin layer 102 and the elastic layer 103 made of rubber or sponge provided on the outer peripheral surface of the resin layer 102. Also, as shown in FIG. 16B, the upper end roller portion 34a includes a rolling bearing 104 provided on the outer peripheral surface of the roller shaft 32a, a resin layer 105 provided on the outer peripheral surface of the rolling bearing 104, And an elastic layer 106 made of rubber provided on the outer peripheral surface of the resin layer 105. Thus, the center roller part 33a and the end roller part 34a of the upper clamping roller 31a have the rolling bearings 101 and 104, respectively, so that they can rotate with respect to the roller shaft 32a.

  On the other hand, the lower central roller portion 33b is fixed so as not to rotate with respect to the roller shaft 32b. Specifically, as shown in FIG. 16A, the lower central roller portion 33b includes a roller base 107 made of metal or resin fixed so as not to rotate with respect to the metal roller shaft 32b, And an elastic layer 108 made of rubber provided on the outer peripheral surface of the roller base 107.

  Unlike the lower central roller portion 33b, the lower end roller portion 34b is provided to be rotatable with respect to the roller shaft 32b. Specifically, as shown in FIG. 16B, a roller shaft 32b is rotatably inserted into a hole portion of the lower end roller portion 34b. That is, a sliding bearing structure is provided in which the inner peripheral surface of the lower end roller portion 34b and the outer peripheral surface of the roller shaft 32b can slide relative to each other in the rotational direction. In the present embodiment, the lower end roller portion 34b is made of a resin roller such as polyacetal (POM) having self-lubricating properties.

Next, the operation (action) of each roller unit during conveyance of the recording medium will be described.
As described above, since the lower end roller portion 34b is rotatably provided with respect to the roller shaft 32b that is a drive shaft, even if the roller shaft 32b rotates, the roller shaft 32b, the end roller portion 34b, If no frictional force is generated between them, the end roller portion 34b does not rotate. However, as shown in FIG. 15, when the pair of sandwiching rollers 31a and 31b are attached to the conveying device and brought into pressure contact with each other, the lower end roller portion 34b is pressed against the roller shaft 32b. A frictional force is generated between the inner peripheral surface of the lower end roller portion 34b and the outer peripheral surface of the roller shaft 32b, or the frictional force is increased. As a result, when the pair of nipping rollers 31a and 31b are in pressure contact with each other, when the lower roller shaft 32b is driven to rotate, the lower end roller portion 34b rotates (follows) together with the roller shaft 32b. For example, when a polyacetal roller having a friction coefficient of about 0.2 is used as the lower end roller portion 34b, the pressing force of the pressure spring 40 is set to about 10 [N], so that the lower end roller portion 34b has a lower end. The roller portion 34b can be rotated together with the roller shaft 32b.

  Further, when the lower central roller portion 33b and the lower end roller portion 34b rotate in accordance with the rotation drive of the roller shaft 32b, the upper central roller portion 33a and the upper end roller portion 34a become the lower central roller. Together with the portion 33b and the lower end roller portion 34b, it is driven to rotate. At this time, when one end portion in the width direction of the recording medium P comes into contact with the lower end roller portion 34b ahead of the other end portion side, the rotation speed (surface movement speed) of the lower end roller portion 34b is brought about by this contact. ) Temporarily changes in accordance with the conveyance speed of the recording medium P. That is, when the conveyance speed of the recording medium P is slower than the rotation speed of the lower end roller section 34b, the rotation speed of the lower end roller section 34b temporarily decreases, and the conveyance speed of the recording medium P decreases. When the rotational speed of the lower end roller portion 34b is higher than the rotational speed of the lower end roller portion 34b, the rotational speed of the lower end roller portion 34b temporarily increases. The rotational speed changes in this way because the lower end roller portion 34b is provided so as to be rotatable with respect to the roller shaft 32b. That is, when the recording medium P comes into contact with the lower end roller portion 34b, an external force is applied to the lower end roller portion 34b by the contact with the recording medium P, so that the lower end roller portion 34b rotates the roller shaft 32b. The speed changes in accordance with the conveyance speed of the recording medium P without being restricted by the recording medium P. Further, when the rotational speed of the lower end roller portion 34b changes, the rotational speed of the upper end roller portion 34a also changes temporarily following this.

  On the other hand, when one end portion in the width direction of the recording medium P comes into contact with the upper end roller portion 34a ahead of the other end portion side, the recording medium P is in contact with the upper end roller portion 34a. External force due to contact is applied. As a result, the upper end roller portion 34a temporarily changes in speed according to the conveyance speed of the recording medium P, and the lower end roller portion 34b also changes temporarily following this.

  Even when one end portion in the width direction of the recording medium P enters between the end roller portions 34a and 34b (nip portion) ahead of the other end portion side, the upper end roller portion 34a and the lower end roller Due to the contact of the recording medium P with the portion 34b, the speeds of the end roller portions 34a and 34b temporarily change in accordance with the conveyance speed of the recording medium P.

  As described above, since the speeds of the end roller portions 34a and 34b change in accordance with the conveyance speed of the recording medium P, the recording medium P does not receive a large contact force or conveyance force from the contacted end roller portions 34a and 34b. . Thereby, the inclination of the recording medium P due to the contact force or the conveying force being applied only to one side of the recording medium P can be suppressed.

  In order to further reduce the contact force acting on the recording medium P due to contact with the end roller portions 34a and 34b, it is desirable that the surface layers (outer peripheral surfaces) of the end roller portions 34a and 34b are made of a low friction material. Examples of the low friction material include resin materials such as polyacetal and metal materials used in the present embodiment. Since the transport device according to the present embodiment is configured to transport the recording medium P in the horizontal direction, the front end portion of the recording medium P tends to face downward, and the lower end roller portion 34b is lower than the upper end roller portion 34a. On the other hand, the tip of the recording medium P tends to come into contact. For this reason, in the present embodiment, only the surface layer of the lower end roller portion 34b that is likely to come into contact with the recording medium P is made of polyacetal (low friction material). In consideration of the case where the recording medium P is curled and the leading end is directed upward, the surface layer of the upper end roller portion 34a may also be made of a low friction material. In this way, by configuring the surface layer of at least one of the upper end roller portion 34a and the lower end roller portion 34b with a low friction material, the influence of the contact force applied to the recording medium P can be further reduced. The inclination of the recording medium P can be further suppressed.

  When only one of the upper end roller portion 34a and the lower end roller portion 34b is made of a low friction material, the recording medium P is preferentially guided to the roller side made of the low friction material. It is good to be able to do it. For example, as in this embodiment, when the surface layer of the lower end roller portion 34b is made of a low friction material, the conveyance guide pair disposed on the upstream side in the conveyance direction of the pair of nipping rollers 31a and 31b is lowered. It arrange | positions near the side clamping roller 31b. Specifically, as shown in FIG. 17, when the distance between the upper conveyance guide 200a and the lower conveyance guide 200b is 2 mm, the intermediate position M between the guide surfaces of the conveyance guide pair 200a, 200b facing each other. However, the conveyance guide pairs 200a and 200b are arranged so as to be positioned 0.5 mm below the tangent line Q that passes through the nip portion N of the pair of sandwiching rollers 31a and 31b and contacts the pair of sandwiching rollers 31a and 31b.

  By disposing the conveyance guide pair 200a, 200b at such a position, the recording medium P can be preferentially guided to the roller side having a low friction coefficient, and the effect of suppressing the tilt occurring when the roller contacts can be more reliably obtained. Be able to. Note that when it is desired to preferentially guide the recording medium P to the upper clamping roller 31a, the intermediate position M between the guide surfaces of the conveyance guide pair 200a, 200b opposite to each other is opposite to the example shown in FIG. The conveyance guide pairs 200a and 200b may be disposed so as to be positioned above the tangent line Q.

  As described above, each of the end roller portions 34a and 34b rotates at a speed changing in accordance with the conveyance speed of the recording medium P, and therefore hardly imparts a conveyance force to the recording medium P. Accordingly, the end roller portions 34a and 34b mainly function as auxiliary roller portions that support the conveyance while sandwiching both ends of the recording medium P, or guide roller portions that guide the recording medium P in the conveyance direction. As described above, the end roller portions 34a and 34b function as auxiliary roller portions or guide roller portions, so that inclination due to contact force or conveyance force being applied to only one side of the recording medium P can be suppressed. At the same time, flapping at both ends in the width direction of the recording medium P can be suppressed and the recording medium P can be stably conveyed. Thereby, it is possible to suppress the occurrence of conveyance failure and noise due to flapping of both ends in the width direction of the recording medium P.

  On the other hand, unlike the end roller portions 34a and 34b, the lower central roller portion 33b is fixed to the roller shaft 32b, so that even if the recording medium P contacts the lower central roller portion 33b, The roller shaft 32b is driven to rotate integrally without being affected by the conveyance speed of the recording medium P. Further, the upper central roller portion 33a is driven to rotate together with the lower central roller portion 33b that is rotationally driven. For this reason, these central roller portions 33a and 33b mainly function as conveyance roller portions that apply conveyance force to the recording medium P.

  As described above, since each of the central roller portions 33a and 33b functions as a transport roller portion, if each of the central roller portions 33a and 33b has a roller diameter deviation or a rubber hardness deviation in the axial direction, this is a recording medium being nipped and conveyed. It becomes a factor of the inclination which arises in P. However, in the present embodiment, the portion that functions mainly as the transport roller portion is only a portion (center roller portions 33a and 33b) provided on the center side in the axial direction of the roller shafts 32a and 32b. It is not provided across. That is, by making the portion that functions as the transport roller portion a short roller portion in the axial direction, even if a roller diameter deviation or a rubber hardness deviation occurs, these deviations can be reduced. Thereby, it is possible to suppress the inclination of the recording medium P caused by the roller diameter deviation or the rubber hardness deviation of the transport roller parts (central roller parts 33a and 33b).

  In order to reduce the inclination of the recording medium P generated during nipping and conveying, it is also effective to reduce the pressure deviation generated between the rollers in addition to reducing the roller diameter deviation and the rubber hardness deviation of the conveying roller portion. Therefore, it is preferable that the pressing position by the pressing spring 40 is as close as possible to the axially central position of the pair of clamping rollers 31a and 31b. In the present embodiment, as shown in FIG. 15, the pressure position by the pressure spring 40 is not at both end portions of the roller shafts 32 a and 33 b (locations outside the end roller portions 34 a and 34 b) but at the end. The roller portions 34a and 34b are located on the inner side in the axial direction and on the outer side in the axial direction than the central roller portions 33a and 33b. As a result, the pressure deviation associated with the deflection of the roller shaft and the deviation of the roller diameter is less likely to occur, so that the inclination of the recording medium P during nipping and conveying caused by this can be suppressed.

  As described above, according to the configuration of the transport device according to the present embodiment, it is possible to suppress the tilt of the recording medium that occurs when entering the nip portion or during nipping and transporting, so that the accuracy of position correction of the recording medium is improved. Thus, highly accurate position correction can be performed. Further, by adopting the configuration of the transport device according to the present embodiment, it is possible to improve the accuracy of position correction without adopting a method of detecting the amount of inclination of the recording medium after entering the nip portion of the roller pair. Therefore, according to the configuration of the conveying device according to the present embodiment, a method of detecting the amount of inclination of the recording medium before entering the nip portion of the roller pair can be adopted. It is possible to secure a time margin until the correction operation is completed. Therefore, according to the present invention, it is possible to provide a transport apparatus that can maintain the transport speed and can perform high-precision position correction while performing high-speed transport.

  In the present embodiment, since the lower end roller portion 34b is made of polyacetal having a low friction coefficient, wear of the inner peripheral portion of the end roller portion 34b that contacts the outer peripheral surface of the metal roller shaft 32b is reduced. Is possible. However, since wear of the lower end roller portion 34b is unavoidable, the lower end roller portion 34b (particularly the inner peripheral portion) may be made of a metal material when wear becomes a problem. In this case, the traction oil (traction grease), which is a driving force transmission fluid, is interposed between the inner peripheral surface of the lower end roller portion 34b and the outer peripheral surface of the roller shaft 32b, whereby the lower end roller portion 34b. The lower end roller portion 34b can be rotated around the roller shaft 32b while suppressing wear of the roller shaft 32b. Traction oil is a lubricant that tends to vitrify under extreme pressure conditions, and maintains a coefficient of friction of about 0.1 under extreme pressure. For this reason, the traction oil is excellent in increasing the slip start torque, and is suitable for drive transmission by friction between the lower end roller portion 34b and the roller shaft 32b. When traction oil is used, if the pressure contact force between the sandwiching rollers 31a and 31b is set high, the friction coefficient is increased by 50% with respect to the friction coefficient when normal oil is used, and the transmittable torque is also increased by 50%.

FIG. 18 is a front view showing the configuration of the pair of clamping rollers 31a and 31b and their peripheral portions according to another embodiment of the present invention.
In the embodiment shown in FIG. 18, the upper roller shaft 32 a is divided into three parts at the axial center and both axial ends, and both ends of each roller shaft 32 a are pressurized by the pressure springs 40. With this configuration, the upper central roller portion 33a and the upper end roller portions 34a are pressurized independently of each other, so that each of them is affected by the roller diameter deviation and rubber hardness deviation of the other roller portions. Pressurized without receiving. As a result, the pressure deviation between the central roller portions 33a and 33b functioning as the transport roller portions is less likely to occur, and the tilt of the recording medium during nipping and transport can be further suppressed.

FIG. 19 is a plan view of a lower sandwiching roller 31b according to another embodiment of the present invention, and FIG. 20 is a side view of the sandwiching roller pair 31a, 31b according to the present embodiment.
In the embodiment shown in FIGS. 19 and 20, the pair of sandwiching rollers 31a and 31b are arranged on the upstream side and the downstream side in the conveying direction, respectively, and the central roller portions 33a and 33b and the end roller portions 34a and 34b are sandwiched separately. The roller pair 31a, 31b is provided. In the present embodiment, center roller portions 33a and 33b are provided on the pair of nipping rollers 31a and 31b on the downstream side in the transport direction (left side in FIG. 20), and the pair of nipping rollers 31a and 31b on the upstream side in the transport direction (right side in FIG. 20). End roller portions 34a and 34b are provided on 31b.

  The attachment structure of the central roller portions 33a and 33b and the end roller portions 34a and 34b with respect to the roller shafts 32a and 32b is the same as that of the above embodiment. That is, the upper central roller portion 33a and the upper end roller portion 34a are provided so as to be rotatable with respect to the roller shaft 32a using the rolling bearings 101 and 104, respectively, and the lower central roller portion 33b is provided with the roller shaft 32b. It is fixed so as not to rotate. Further, the lower end roller portion 34b is rotatably provided with a sliding bearing structure with respect to the roller shaft 32b, and is configured to rotate together with the roller shaft 32b in a state in which the pair of sandwiching rollers 31a and 31b are in pressure contact with each other. Has been. Further, the lower roller shafts 32a are configured so that the driving force from the motor 61 can be transmitted from one to the other via a timing belt 201 which is a power transmission member.

  In the present embodiment, when the recording medium P is transported, as shown in FIG. 21A, the recording medium P is transported while being sandwiched between the central roller portions 33a and 33b and the end roller portions 34a and 34b. At this time, the operation of the central roller portions 33a and 33b and the end roller portions 34a and 34b with respect to the recording medium P is the same as in the above-described embodiment. That is, the end roller portions 34a and 34b function as auxiliary roller portions or guide roller portions, and the central roller portions 33a and 33b function as transport roller portions. At this time, the central roller portions 33a and 33b and the end roller portions 34a and 34b are integrally rotated or moved in the width direction based on the detection results of the skew detection sensor 35 and the CIS 36, so that the recording medium P The inclination or the lateral deviation is corrected.

  Thereafter, as shown in FIG. 21 (b), when the recording medium P is conveyed and its leading end is sandwiched between the timing roller pair 15, the central roller portions 33a and 33b are separated from each other. As described above, the central roller portions 33a and 33b are separated from each other, so that the conveyance force of the central roller portions 33a and 33b can be prevented from interfering with the conveyance force of the timing roller pair 15. That is, even when there is a difference in the conveyance speed between the central roller portions 33a and 33b and the timing roller pair 15, it is possible to avoid the influence on the recording medium P, and the recording medium P to the transfer portion 7 can be avoided. It is possible to prevent the conveyance timing of the recording medium from being shifted and the recording medium P from being wrinkled.

  On the other hand, the end roller portions 34a and 34b are held in pressure contact with each other even when the central roller portions 33a and 33b are separated from each other. Thereby, the end roller portions 34a and 34b prevent the posture change of the recording medium P and the flapping of both ends in the width direction, and the recording medium P can be stably conveyed.

  Thus, in this embodiment, even if the central roller portions 33a and 33b are separated from each other, the end roller portions 34a and 34b can be held in pressure contact with each other. That is, in the present embodiment, since the central roller portions 33a and 33b and the end roller portions 34a and 34b are provided in separate sandwiching roller pairs 31a and 31b, the other is held in a pressure contact state while separating one. Can be easily realized. Thereby, interference with the conveying force of the timing roller pair 15 can be avoided, and flapping at both ends of the recording medium P can be suppressed, and the recording medium P can be conveyed with high accuracy and stability.

FIG. 22 is a front view of a transport apparatus according to still another embodiment of the present invention.
In the embodiment shown in FIG. 22, the support shaft 73 of the holding frame 72 is juxtaposed with the two-stage spline coupling 65 in a direction substantially perpendicular to the rotation axis direction of the sandwiching roller pair 31. That is, the support shaft 73 is disposed at a position directly below the two-stage spline coupling 65. When configured in this manner, the deflection angle generated in the two-stage spline coupling 65 can be reduced when the clamping roller pair 31 (holding frame 72) is rotated along with the inclination correction. For this reason, it is possible to transmit the rotational driving force transmitted from the motor 61 to the clamping roller pair 31 via the two-stage spline coupling 65 with higher accuracy.

  While the embodiments of the present invention have been described above, the embodiments described with reference to FIGS. 18 to 22 are the same as those described with reference to FIGS. 1 to 17 except for the portions described above. Therefore, explanation is omitted.

  Further, the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention. In the above-described embodiment, the lower sandwiching roller 31b of the pair of sandwiching rollers 31a and 31b is a drive roller and the upper sandwiching roller 31a is a driven roller. However, the relationship between driving and driven may be reversed. In this case, the same effect as described above can be obtained by turning the configuration shown in FIGS. 15 and 16 upside down. In the above-described embodiment, the position of the side end portion on one side in the width direction of the recording medium P is detected by the CIS 36. However, the CIS 36 is arranged over the entire width direction of the recording medium P, and the recording medium P is arranged. The positions of the side end portions on both sides in the width direction may be detected.

  Further, the configuration of the present invention may be applied to the timing roller pair 15. In this case, since the inclination of the recording medium during the nip entry or the nipping conveyance in the timing roller pair 15 can be suppressed, the recording medium is moved downstream while maintaining the posture corrected by the upstream nipping roller pair 31a, 31b. It becomes possible to convey to the transfer section on the side.

  In addition, the present invention is not limited to a conveyance device that conveys transfer paper, but can also be applied to a conveyance device (original conveyance unit 10) that conveys a document. Further, the conveying device according to the present invention is not limited to the one mounted on the monochrome image forming apparatus as shown in FIG. 1, but the one mounted on the color image forming apparatus or the image forming apparatus other than the electrophotographic system. (For example, an inkjet image forming apparatus, an offset printing machine, or the like) may be mounted. The present invention is not limited to a conveyance device mounted on an image forming apparatus, but can be applied to a conveyance device that conveys a medium to be conveyed such as an electronic substrate.

1 Copying machine (image forming device)
30 Conveying device 31a Nipping roller 31b Nipping roller 32a Roller shaft 32b Roller shaft (drive shaft)
33a Central roller portion 33b Central roller portion 34a End roller portion 34b End roller portion 200a Conveying guide 200b Conveying guide P Recording medium (conveyed medium)

JP 2014-88263 A

Claims (10)

A conveying device comprising a roller pair that conveys the medium to be conveyed by rotating in a state of being pressed against each other and sandwiching the medium to be conveyed,
One roller of the roller pair is
A drive shaft for rotational driving;
A central roller portion provided on the axially central side of the drive shaft so as not to rotate with respect to the drive shaft;
An end roller portion provided to be rotatable relative to the drive shaft at both axial ends of the drive shaft with respect to the central roller portion;
Have
The end roller portion rotates with the rotation of the drive shaft by a frictional force generated between the end roller portion and the drive shaft in a state of being pressed against the other roller of the roller pair. Conveying device to do.   The conveying device according to claim 1, wherein a position to press the roller pair so as to be in pressure contact with each other is on the inner side in the axial direction than the end roller portion and on the outer side in the axial direction from the central roller portion.   The conveying device according to claim 1 or 2, wherein a surface layer of the end roller portion is made of a low friction material. The roller pair is
An upper roller;
A lower roller disposed below the upper roller;
Have
4. The conveyance according to claim 3, wherein the lower roller is a roller in which the central roller portion and the end roller portion are provided on the drive shaft, and a surface layer of the end roller portion is made of a low friction material. apparatus. An upper side and a lower side are arranged opposite to each other, and includes a conveyance guide pair that guides the medium to be conveyed to the roller pair,
The transport apparatus according to claim 4, wherein an intermediate position between the guide surfaces facing each other of the transport guide pair is located below a tangent line passing through a nip portion of the roller pair and in contact with the roller pair. The drive shaft is made of a metal material,
The conveying apparatus according to any one of claims 1 to 5, wherein an inner peripheral portion of the end roller portion that is in contact with an outer peripheral surface of the drive shaft is formed of a resin material. Both the drive shaft and the inner peripheral portion of the end roller portion that contacts the outer peripheral surface are made of a metal material,
The conveying device according to any one of claims 1 to 5, wherein a driving force transmission fluid is interposed between an outer peripheral surface of the driving shaft and an inner peripheral surface of the end roller portion. A plurality of the roller pairs are provided,
The central roller portion and the end roller portion are provided on separate drive shafts of the roller pair,
The conveying device according to claim 1, wherein the roller pair provided with the central roller portion is configured to be able to contact and be separated from each other.   9. The roller pair according to claim 1, wherein the pair of rollers can reciprocate in a width direction of the transported medium, and can rotate in an inclination direction of the transported medium and a direction opposite thereto. Conveying device.   An image forming apparatus comprising the transport device according to claim 1.

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