JP6579062B2 - Sheet conveying apparatus and image forming apparatus - Google Patents

Description

    The present invention relates to an image forming apparatus including a sheet conveying apparatus that conveys a sheet.

  2. Description of the Related Art Image forming apparatuses such as copying machines and printers are provided with a sheet conveying apparatus that conveys a sheet to an image forming unit along a conveying path. The sheet conveying apparatus includes a pickup roller that sends out a sheet, and a paper feeding roller that feeds and conveys the sheets sent out by the pickup roller one by one. In addition, the conveyance path is provided with a pair of registration rollers for correcting the skew of the sheet conveyed by the sheet feeding roller on the downstream side in the conveyance direction from the sheet conveyance apparatus.

  Further, depending on the layout of the conveyance path and the like, as described in Patent Document 1, an intermediate roller pair that assists the conveyance of the sheet may be disposed between the paper feed roller and the registration roller pair. Generally, the intermediate roller pair includes a rubber roller and a resin pulley that are pressed against each other. In order to sufficiently secure the sheet conveying force, it is necessary to widen the width of the nip between the roller and the pulley.

JP 2013-184821 A

  By the way, when a resin pulley is molded using a mold, an outer diameter difference is generated in the axial direction of the pulley due to a draft. Then, there is a difference in the sheet conveyance speed in the axial direction, and the sheet may skew in a predetermined direction. The greater the nip width between the roller and pulley, the more pronounced the skew. When there is one pair of intermediate rollers disposed between the paper feed roller and the registration roller pair, if the degree of skew is large, the skew may not be reliably corrected by the registration roller pair. Moreover, when there are a plurality of pairs of intermediate rollers, there is a problem that the sheet is easily bent and wrinkled between the pairs of intermediate rollers.

  SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide an image forming apparatus including a sheet conveying device that can prevent a skew and a wrinkle generated in a pair of intermediate rollers and can move a sheet straight.

  In order to solve the above-described problem, a sheet conveying apparatus according to the present invention includes a sheet placing unit on which a sheet is placed, a conveying path on which a sheet placed on the sheet placing unit is conveyed, and the conveying path. A conveying member that conveys the sheet along the conveying path, and the conveying member includes a driving roller and a driven roller that is pressed against the driving roller and is driven to rotate, and the driven roller. Has a rotating shaft and a roller body rotatably supported by the rotating shaft, and the roller body is arranged in at least two roller portions that can be independently rotated in the axial direction of the rotating shaft. It is characterized in that it is divided and at least two roller parts that can rotate independently of each other.

  By adopting such a configuration, when skew is likely to occur in the sheet due to the shape of the roller section, the appearance of the skew is dispersed by the individual rotation of the roller section. Can be made.

  In the sheet conveying apparatus of the present invention, the at least two roller portions are resin molded products molded using a mold, and the axial direction of the rotating shaft is in a direction in which the direction of the draft of the mold is different. It is good also as the characteristic that it is arranged.

  By adopting such a configuration, even when the roller portion of the resin molded product is used, the appearance of skew is dispersed, so that the sheet can be straightened more reliably.

  In the sheet conveying apparatus of the present invention, the roller body has two roller portions, and the two roller portions are formed to have a large diameter with end portions formed to have a small diameter by a draft angle facing each other in opposite directions. It is good also as the feature that it arrange | positions so that the edge part may mutually oppose.

  By adopting such a configuration, the conveyance speed at the center of the sheet is increased, so that wrinkles can be prevented from occurring.

In the sheet conveying apparatus of the present invention, the conveying member may be arranged in a central portion in the width direction of the sheet orthogonal to the conveying direction.

  By adopting such a configuration, even if the width of the conveying member is reduced, the sheet can be stably conveyed regardless of the size of the sheet.

  The sheet conveying apparatus of the present invention is disposed on the downstream side in the conveying direction of the sheet feeding roller, and feeds the sheet placed on the sheet placing portion to the conveying path, and the leading edge of the sheet is applied. A pair of registration rollers for correcting a skew of the sheet by forming a loop in contact with the sheet, and a pair of intermediate rollers disposed in the conveyance path between the sheet feeding roller and the pair of registration rollers The conveying member may be the intermediate roller pair.

  By adopting such a configuration, the sheet can be conveyed without causing bending or wrinkling.

  An image forming apparatus according to the present invention includes any one of the sheet conveying apparatuses described above, and an image forming unit that forms an image on a sheet conveyed by the sheet conveying apparatus.

  According to the present invention, since the appearance of the skew is dispersed by rotating the roller portions individually, it is possible to prevent the skew of the sheet and to advance straight.

1 is a side view schematically showing an internal structure of a printer according to an embodiment of the present invention. 1 is a perspective view illustrating a part of a sheet conveying apparatus according to an embodiment of the present invention. In the sheet conveying apparatus which concerns on one Embodiment of this invention, it is a top view which shows an intermediate | middle roller pair. In the sheet conveying apparatus which concerns on one Embodiment of this invention, it is a top view which shows a driven roller. In the sheet conveying apparatus which concerns on one Embodiment of this invention, it is a top view which shows the modification of a driven roller.

  Hereinafter, an image forming apparatus and a sheet conveying apparatus according to an embodiment of the present disclosure will be described with reference to the drawings.

  First, an overall configuration of a printer 1 as an image forming apparatus will be described with reference to FIG. FIG. 1 is a schematic diagram showing an outline of a printer. In the following description, the front side of the page in FIG. 1 is the front side (front side) of the printer 1, and the left and right directions are based on the direction when the printer 1 is viewed from the front.

  The apparatus main body 2 of the printer 1 includes a sheet conveying device 4 that feeds the sheet S, an image forming unit 6 that forms a toner image on the fed sheet S, and a fixing device 7 that fixes the toner image on the sheet S. And a discharge device 8 for discharging the sheet S on which the toner image is fixed, and a discharge tray 9 for receiving the discharged sheet S.

  In the apparatus main body 2, a conveyance path 10 through which the sheet S is conveyed from the sheet conveyance device 4 through the image forming unit 6 and the fixing device 7 toward the discharge device 8 is formed. The conveyance path 10 includes a curved portion 10 a that is curved by approximately 180 ° toward the image forming unit 6 in the sheet conveying device 4. The conveyance path 10 is formed so as to extend in a substantially horizontal direction from the curved portion 10 a to the fixing device 7 through the image forming portion 6 and to be curved upward from the fixing device 7 to the discharge device 8.

  Next, the sheet conveying device 4 will be described with reference to FIGS. 1 and 2. FIG. 2 is a perspective view showing a part of the sheet conveying apparatus. The sheet conveying device 4 includes a sheet placing unit 21 on which the sheet S is placed, a pickup roller 22, a sheet feeding roller 23, and a conveyance that are sequentially arranged from the sheet placing unit 21 toward the downstream side in the conveying direction. An intermediate roller pair 24 as a member and a registration roller pair 5 are provided.

  The sheet placing portion 21 is formed in a tray shape having a dimension capable of placing a sheet. A pair of side cursors 31 that regulate the width direction of the sheet S orthogonal to the transport direction are supported on the sheet placement unit 21 so as to be slidable in the width direction. Further, an end cursor 32 that regulates the rear end of the sheet S in the transport direction is supported by the sheet placement unit 21 so as to be slidable in the transport direction. Further, the sheet placement portion 21 supports a placement plate 33 on which the sheet S is placed so as to be rotatable around the upstream end portion in the transport direction. The downstream end of the loading plate 33 in the conveyance direction is urged upward by an urging member (not shown), and the downstream end of the sheet S placed on the loading plate 33 is directed upward. It is held in an inclined posture. A friction pad 34 is attached to the center in the width direction of the downstream end of the mounting plate 33 in the conveying direction.

  The pickup roller 22 has a rotating shaft 22a and a roller body 22b provided so as to be rotatable integrally with the rotating shaft 22a. The pickup roller 22 is rotatably supported at the center in the width direction above the downstream end of the mounting plate 33. When the mounting plate 33 on which the sheet S is mounted rotates to the above-described tilted posture, the sheet S is sandwiched between the friction pad 34 and the roller body 22b, and is sent to the downstream side as the pickup roller 22 rotates. .

  The paper feed roller 23 has a rotation drive shaft 23a and a roller body 23b provided so as to be rotatable integrally with the rotation drive shaft 23a. The paper feed roller 23 is supported at the center in the width direction on the downstream side in the transport direction of the pickup roller 22. The rotational drive shaft 23a is rotationally driven by a drive source (not shown) such as a motor. The paper feed roller 23 is connected to the pickup roller 22 via an idle gear or a timing belt. Accordingly, the pickup roller 22 is rotated in the same direction as the paper feed roller 23 as the paper feed roller 23 is rotated in the transport direction (counterclockwise direction in FIG. 1).

  A separation roller 35 is pressed against the paper feed roller 23 from below to form a separation nip between the paper feed roller 23 and the separation roller 35. When the paper feed roller 23 rotates, the separation roller 35 is driven to rotate in the direction opposite to that of the paper feed roller 23, and the sheet S sent to the separation nip is conveyed.

  The separation roller 35 stops rotating until a constant torque is applied, and rotates when the torque equal to or greater than a predetermined value is applied. When the sheet S sent out from the pickup roller 22 is a single sheet, the torque applied to the separation roller 35 is larger than a certain value, so that the separation roller 35 is rotated by the paper feed roller 23 to convey the sheet S. . On the other hand, when a plurality of sheets S are sent out, the torque applied to the separation roller 35 becomes a certain value or less, and the uppermost sheet S moves downward by stopping the sheet S with the sheet feeding roller 23 interposed therebetween. The sheet S is separated and conveyed downstream by the sheet feeding roller 23.

  Next, the intermediate roller pair 24 will be described with reference to FIGS. 3 and 4. FIG. 3 is a plan view showing the driving roller and the driven roller, and FIG. 4 is a plan view showing the driven roller.

  As shown in FIG. 1, the intermediate roller pair 24 includes a driving roller 41 disposed on the inner peripheral side of the transport path 10 and a driven roller 42 disposed on the outer peripheral side of the transport path 10. . The intermediate roller pair 24 is disposed in the center in the width direction in the vicinity of the top of the curved portion 10 a of the conveyance path 10 between the paper feed roller 23 and the registration roller pair 5.

  As shown in FIG. 3, the drive roller 41 includes a rotation drive shaft 41 a and a roller body 41 b provided on the rotation drive shaft 41 a so as to be integrally rotatable. The roller body 41 b is made of, for example, rubber, and has a wider width than the roller body 23 b of the paper feed roller 23. The rotational drive shaft 41a is rotationally driven by a drive source (not shown) such as a motor.

  As shown in FIG. 4, the driven roller 42 includes a rotating shaft 51 and a roller body 52 that is rotatably supported by the rotating shaft 51. The roller body 52 is divided into two roller portions 53 that can rotate independently of each other in the axial direction of the rotation shaft 51. The two roller portions 53 are arranged at a predetermined interval d, and are restricted from moving in the axial direction of the rotation shaft 51. The distance d between the two roller parts 53 is preferably as narrow as possible. In addition, the width W between both ends of the two roller portions 53 is wider than the width of the roller body 41 b of the drive roller 41.

  The two roller parts 53 are demonstrated with reference to FIG. FIG. 5 is a plan view showing the shapes and arrangement examples of the two roller portions.

  The two roller portions 53 are molded products obtained by molding a resin using a mold, and are arranged so that the draft angles are opposite to each other, as shown in FIG. Specifically, the end portions 53a formed to have a small diameter due to the draft angle face each other, and the end portions 53b formed to have a large diameter face each other.

  As shown in FIG. 4, both end portions of the rotation shaft 51 of the driven roller 42 are urged toward the drive roller 41 by coil springs 55, respectively. Thereby, the two roller parts 53 are press-contacted with the roller body 41b of the drive roller 41, and a nip is formed between the two roller parts 53 and the roller body 41b. When the sheet S is conveyed to the nip, the drive roller 41 rotates and is conveyed downstream.

  As illustrated in FIG. 1, the registration roller pair 5 includes a driving roller 61 and a driven roller 62 that is pressed against the driving roller 61. The drive roller 61 is driven to stop rotating at a predetermined timing. When the driving roller 61 stops rotating, the leading edge of the sheet comes into contact with the nip between the driving roller 61 and the driven roller 62.

  The sheet conveying operation of the sheet conveying apparatus 4 having the above configuration will be described. The position of the sheet S placed on the placement plate 33 of the sheet placement unit 21 shown in FIG. 2 is regulated by the pair of side cursors 31 and end cursors 32 in the width direction and the conveyance direction, respectively. Thereafter, when the rotation driving shaft 23a of the paper feed roller 23 is driven to rotate the pickup roller 22 and the paper feed roller 23, the pickup roller 22 causes the sheet to enter the separation nip between the paper feed roller 23 and the separation roller 35. S is sent out. In the separation nip, the sheet S is rolled as described above, and the sheets S are conveyed one by one from the separation nip to the conveyance path 10. The sheet S that has passed through the separation nip is conveyed to the nip between the pair of intermediate rollers 24 and is conveyed downstream by the conveyance force generated between the driving roller 41 and the driven roller 42.

  Here, since the two roller portions 53 of the driven roller 42 of the intermediate roller pair 24 have different draft directions as shown in FIG. 5A, the two roller portions 53 have different outer diameters. The appearance of the skew is offset, and the skew is less likely to occur in the sheet S. In particular, the two roller portions 53 are arranged so that the end portions 53a formed with a small diameter by the draft angle face outward and the end portions 53b formed with a large diameter face each other. That is, as for the two roller parts 53, the center side as a whole has a large diameter and both ends have a small diameter. Accordingly, the conveyance speed of the central portion of the sheet S is increased, and the central portion of the sheet S is conveyed so as to be pulled, so that wrinkles are hardly generated.

  Further, since the width of the roller body 41b of the drive roller 41 is wider than the width of the roller body 23b of the paper feed roller 23, paper dust generated due to friction between the paper feed roller 23 and the sheet S is difficult to pass, and the paper Generation of image unevenness due to powder is prevented. Furthermore, since the width W between both ends of the two roller portions 53 of the driven roller 42 is wider than the width of the roller body 41 b of the driving roller 41, there is an influence of a step generated at the ends when the two roller portions 53 are formed. It becomes difficult to reach the sheet S, and the generation of fold lines can be prevented.

  When the sheet S conveyed from the intermediate roller pair 24 is conveyed to the registration roller pair 5, the driving roller 61 of the registration roller pair 4 stops rotating. As a result, the leading edge of the conveyed sheet S comes into contact with the nip between the driving roller 61 and the driven roller 62. However, since the driving roller 41 of the intermediate roller pair 24 is rotating, the sheet S is continuously conveyed by the intermediate roller pair 24. As a result, a loop is formed in the sheet S and the skew of the sheet S is corrected until the entire front end of the sheet S comes into contact with the nip. Thereafter, when the driving roller 61 of the registration roller pair 5 is rotated at a predetermined timing, the sheet S is conveyed from the nip to the image forming unit 6 on the downstream side.

  As described above, according to the sheet feeding device 4 of the present invention, the roller body 52 of the driven roller 42 of the intermediate roller pair 24 is configured by the two roller portions 53 that rotate independently of each other. Thus, the skew of the sheet S is less likely to occur. Therefore, the skew can be corrected more accurately by the registration roller pair 5. Therefore, the sheet S can be moved straight with a simple configuration.

  Further, the two roller portions 53 are arranged so that the end portions 53a formed with a small diameter by a draft angle face each other and the end portions 53b formed with a large diameter face each other. Large diameter and small diameter at both ends. As a result, the conveyance speed of the central portion of the sheet S is increased and the central portion of the sheet S is pulled, so that wrinkles can be prevented from occurring.

  Moreover, the width | variety of each roller part 53 becomes narrow because the roller part 53 of the driven roller 42 was made into two. For this reason, the outer diameter difference due to the draft is reduced, and the degree of skew can be reduced.

  As shown in FIG. 5B, the direction of the draft angle of the two roller portions 53 is such that the end portions 53a formed to have a small diameter by the draft angle face each other and the end portions 53b formed to have a large diameter. May be arranged so that they face each other. Alternatively, as shown in FIG. 5C, the draft direction may be the same. Also in such a case, since the roller parts 53 rotate independently of each other, the appearance of the skew is dispersed, and the skew can be hardly generated. Further, the number of roller portions 53 may be two or more. Alternatively, the roller portion 53 may be other than a resin molded product. In this case, even if an outer diameter difference in the axial direction of the roller portion 53 occurs in the formation process of the roller portion 53, the influence of the outer diameter difference is less likely to appear due to the individual rotation of the roller portion 53. Can be transported.

  In this embodiment, since the pair of intermediate rollers 24 is disposed between the paper feed roller 23 and the registration roller pair 5, it is possible to prevent the sheet S from being bent or wrinkled. However, depending on the layout and length of the conveyance path 10 between the paper feed roller 23 and the registration roller pair 5, a plurality of intermediate roller pairs 24 may be arranged.

  In addition, since the pickup roller 22, the paper feed roller 22, the separation roller 25, the intermediate roller pair 24, and the registration roller pair 5 are disposed in the center in the width direction, the sheet S can be stably conveyed regardless of the size of the sheet S. can do.

  The above description of the embodiment of the present invention describes a preferred embodiment of the sheet conveying apparatus and the image forming apparatus according to the present invention, and therefore may have various technically preferable limitations. However, the technical scope of the present invention is not limited to these embodiments unless specifically described to limit the present invention. That is, the above-described components in the embodiment of the present invention can be appropriately replaced with existing components and the like, and various variations including combinations with other existing components are possible. The description of the embodiment of the present invention described above does not limit the contents of the invention described in the claims.

1 Printer (image forming device)
4 Sheet conveying device 5 Registration roller pair 21 Sheet placement unit 23 Paper feed roller 24 Intermediate roller pair (conveying member)
41 Drive roller 42 Followed roller 51 Rotating shaft 52 Roller body 53 Roller part

Claims (4)

A sheet placement section on which the sheet is placed;
A conveyance path along which a sheet placed on the sheet placement unit is conveyed along a predetermined conveyance direction ;
A sheet feed roller that is disposed at a central portion in the width direction of the sheet orthogonal to the transport direction in the transport path, and that feeds the sheet placed on the sheet placement section to the transport path;
A pair of registration rollers arranged on the downstream side in the transport direction from the paper feed roller;
Near the top of the curved portion of the conveyance path between the paper feed roller and the registration roller pair, the conveyance member is disposed in the center in the width direction and conveys the sheet along the conveyance path,
The conveying member is
A driving roller, and a driven roller that is pressed against and rotated by the driving roller,
The drive roller is
A first rotating shaft and a first roller body supported so as to be integrally rotatable with the first rotating shaft;
The driven roller is
And a second rotary shaft, and a second roller member rotatably supported on the second rotating shaft and
The second roller body is divided in the axial direction of the second rotation shaft into at least two roller portions that can rotate independently of each other ,
The first roller body has a width wider than the third roller body of the paper feed roller,
The sheet conveying apparatus , wherein a width between both ends of the two roller portions is wider than a width of the first roller body . The at least two roller parts are resin molded products molded using a mold,
The sheet conveying apparatus according to claim 1, wherein the molds are arranged along the axial direction of the rotating shaft in different directions of the draft angle. The roller body has two roller parts,
3. The two roller portions are arranged such that end portions formed to have a small diameter by a draft angle face in opposite directions, and end portions formed to have a large diameter face each other. The sheet conveying apparatus according to 1. The sheet conveying device according to any one of claims 1 to 3 ,
An image forming unit that forms an image on the sheet conveyed by the sheet conveying device;
An image forming apparatus comprising:

Images