JP2005219904A - Paper conveying device, and image forming device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper conveying device capable of reducing the deflection of a follower roller and a rotary shaft having the same in the paper conveying direction, and to provide an image forming device having the same. <P>SOLUTION: The paper conveying device 1 having a drive roller 2 for conveying a paper and the follower roller 4 has a sheet spring (regulation member) 7 for regulation so that the paper conveying device 1 comes into contact with a follower roller shaft 5, thus regulating the move of the follower roller 4 in the paper conveying direction, and stably conveying the paper along with a screw coil spring 6 for pressure-welding that is provided so that it comes into contact with the follower roller shaft 5. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sheet conveying device and an image forming apparatus including the same, and more specifically, in a sheet conveying apparatus including a driving roller and a driven roller driven by rotation of the driving roller, the driven roller at the time of conveying the sheet. In addition, the present invention relates to a sheet conveying apparatus that reduces bending in a sheet conveying direction of a rotation shaft including the same and an image forming apparatus including the sheet conveying apparatus.

  In an image forming apparatus such as a printer or a copying machine, several sheet conveying apparatuses for feeding, conveying, and discharging a sheet for forming an image are installed in the image forming apparatus.

  In an image forming apparatus provided with such a paper transport device, the image has not been formed in the correct position on the paper so far, the image is formed obliquely on the paper, or the paper transport is not successful and the image formation There has been a problem that a paper jam occurs in the apparatus. The main cause of these problems is in a paper transport device that transports paper.

  The sheet transport device includes two rollers facing each other. One of these rollers is a driving roller, and this driving roller drives the other driven roller. The sheet is conveyed by rotating while the two rollers are pressed. However, when the paper is transported between the driving roller and the driven roller, the driven roller moves in a direction away from the driving roller by the thickness of the paper, that is, in a direction opposite to the direction of load on the driven roller. If the driven roller moves in a direction away from the driven roller and bends, the sheet conveying device becomes weak in conveying force, and it becomes difficult to convey the sheet to be conveyed next.

  Depending on the application, the image forming apparatus may use paper that is thicker and harder than paper that is generally used frequently, such as paper that is small in size, such as postcards, and cardboard. is there. In such a case, the above-described problem appears remarkably, so that the performance as the image forming apparatus is significantly lowered.

  Therefore, a paper transport device has been developed to solve the above-described problems. That is, there is provided means for returning the driven roller that has been moved away from the drive roller to the original position. Specifically, the paper conveying device disclosed in Patent Document 1 includes a leaf spring having elasticity. The leaf spring is in contact with a rotation shaft provided with a driven roller, and always has a force in the direction of the driving roller with respect to the driven roller. Therefore, by providing the leaf spring, even if the driven roller moves away from the drive roller, the driven roller is returned to the original position after the conveyed paper is conveyed from the paper conveying device. Therefore, the above-described problems are solved, and the paper can be efficiently conveyed.

  Further, the paper conveying device disclosed in Patent Document 2 includes a bearing piece. By the bearing piece in contact with the rotating shaft provided with the driven roller, the driven roller moved in the direction away from the driving roller by the thickness of the sheet can be returned to the original position. Since the bearing piece is provided in contact with the rotating shaft provided with the driven roller, the driven roller that has moved in the direction away from the driving roller can be returned to the original position as in Patent Document 1. As a result, the paper conveying apparatus provided with the bearing piece can also solve the above-described problems and efficiently convey the paper.

The above-described conventional paper transport device will be described with reference to FIG. FIG. 6 is a cross-sectional view showing a configuration of a sheet conveying apparatus in the prior art. As shown in FIG. 6A, the sheet conveying apparatus 100 includes a driven roller 101 and a driving roller 102 that face each other, and each rotates about a rotation axis. The sheet conveying device 100 is provided with a torsion coil spring 6 for pressure contact for preventing bending in the direction opposite to the load direction in the direction of the driving roller 102, and the driven roller 101 and the driven roller shaft. A load in a direction opposite to the bending, that is, a direction approaching the driving roller 102 is applied to the 103.
Japanese Patent Laid-Open No. 1-220650 (Publication Date: September 4, 1989) Japanese Utility Model Publication No. 5-46449 (publication date: June 22, 1993)

  However, in the paper transport device as described above, the rotary shaft having the driven roller driven by the rotation of the driving roller among the rotary shafts having two opposed rollers constituting the paper transport device is There arises a problem of bending in the paper transport direction.

  Specifically, it is as follows. As shown in FIG. 6A, the paper conveying apparatus 100 according to the prior art has a torsion coil spring 6 for press contact for preventing the sheet conveying apparatus 100 from bending in the direction opposite to the load direction toward the drive roller 102. The load is applied to the driven roller 101 and the driven roller shaft 103 in the direction opposite to the bending, that is, the direction approaching the driving roller 102. Accordingly, it is possible to prevent the driven roller 101 and the driven roller shaft 103 from being bent in a direction opposite to the load direction in the direction of the driving roller 102 during the conveyance of the paper. However, even when the paper conveying device 100 including the torsion coil spring 6 for pressure contact is used, the above-described image is not formed on the paper at the correct position but is formed obliquely, or the paper is in the image forming apparatus. The problem of causing paper jams was not completely resolved.

  As a result of examining this cause, it was found that the positions of the driven roller 101 and the driven roller shaft 103 in a state where the sheet conveying apparatus is not operated are bent in the sheet conveying direction when the apparatus is operated. .

  More specifically, in the sheet conveying apparatus 100 including the driving roller 102 and the driven roller 101, when the driving roller 102 is driven, the driven roller shaft 103, which is a rotating shaft that supports the driven roller 101, is received. It was found that in the driven roller bearing, a bending moment due to the frictional force that the driven roller receives from the driving roller and the force that the driven roller shaft receives from the bearing is applied to the driven roller shaft, and the driven roller shaft is bent in the paper transport direction. .

  FIG. 6B is a cross-sectional view of the sheet conveying apparatus 100 showing a state in which the positions of the driven roller 101 and the driven roller shaft 103 are bent in the sheet conveying direction during sheet conveyance. In a state where the sheet conveying apparatus 100 is not operated, the driven roller 101 is formed at a position as indicated by a solid line. However, when the paper transport device 100 is operated and the paper is transported, the positions of the driven roller 101 and the driven roller shaft 103 are bent in the paper transport direction as indicated by the dotted lines.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to follow driven by the rotation of a driving roller among the respective rotating shafts having two opposed rollers constituting the sheet conveying device. An object of the present invention is to realize a paper transport device in which a rotation shaft provided with a roller reduces bending in the paper transport direction during paper transport.

  In order to solve the above problems, a sheet conveying apparatus according to the present invention is a sheet conveying apparatus having a driving roller and a driven roller for conveying a sheet, and a restriction for restricting movement of the driven roller in the sheet conveying direction. It is characterized by having a member.

  By providing the above configuration, it is possible to prevent the driven roller from moving in the sheet conveying direction, that is, bending, which has been a problem in the sheet conveying apparatus including the driving roller and the driven roller driven by the driving roller.

  Therefore, it is possible to prevent paper meandering and paper clogging caused by a decrease in the conveying force of the driven roller due to bending of the driven roller in the paper conveying direction, and paper conveyance capable of stable paper conveyance. There exists an effect that an apparatus can be provided.

  Further, the sheet conveying apparatus according to the present invention is characterized in that the regulating member has elasticity.

  As a result, a dimensional error due to the dimensional accuracy and assembly accuracy of the components can be absorbed by the restriction member, which is an elastic member, so that it is possible to achieve stable paper conveyance.

  Further, even when a regulating member for regulating the movement of the driven roller is newly provided for the conventional paper conveying device, the steps such as the arrangement position of the driven roller in the manufacturing of the paper conveying device are as follows. This can be carried out without change, and there is an effect that it is possible to provide a paper transport device capable of stable paper transport without greatly changing the manufacturing efficiency of the paper transport device.

  In the sheet conveying device according to the present invention, the predetermined surface of the regulating member is a surface formed by the axis of the driven roller shaft and the shaft center of the driving roller shaft that supports the driving roller. From the parallel position to a position rotated by less than 90 ° in the rotational direction of the driven roller from the parallel position at a position on the paper discharge side with respect to the surface. It is characterized by being in contact with each other.

  In other words, by bringing the regulating member into contact with the driven roller shaft within the above-described range, the regulating member can return the driven roller and the driven roller shaft bent in the paper transport direction from a predetermined position to the original position. If the restricting member is not in contact with the above range, for example, if it is contacted at a position rotated from the parallel position to the opposite side of the rotation direction of the driven roller, the restricting member is bent in the sheet conveying direction. The driven roller and the driven roller shaft are moved to the paper carry-in side from the predetermined position by the restriction member. By providing such a restriction member, the driven roller and the driven roller shaft are bent toward the paper carry-in side from the original position.

  Therefore, by contacting the regulating member in the above-described range, it is possible to efficiently prevent the meandering of the paper and the paper jam caused by the decrease in the conveying force of the driven roller due to the bending of the driven roller in the paper conveying direction. can do. In other words, there is an effect that it is possible to provide a paper transport device capable of stable paper transport.

  Further, the sheet conveying apparatus according to the present invention is characterized in that the regulating member is a leaf spring.

  As a result, since the occupied area is not large even if the restriction member is provided, it is possible to provide a paper transport device capable of stable paper transport without changing the size of the conventional paper transport device. Play.

  The sheet conveying apparatus according to the present invention is characterized in that the leaf spring is a bending spring.

  As a result, there is an effect that the regulating member can be installed in a very small occupation range in the sheet conveying apparatus.

  In addition, by using a bending spring, a leaf spring with a large secondary moment of inertia and a leaf spring with a small spring constant is provided, and there is no need to strictly measure the dimensional accuracy and assembly accuracy of the parts. The manufacturing method of the transport device can be used, and an effect is provided that a paper transport device capable of stable paper transport can be provided.

  In the sheet conveying apparatus according to the present invention, the restricting member biases a driven roller shaft that supports the driven roller.

  Accordingly, a paper transport device that can prevent the driven roller from being bent in the paper transport direction without hindering the function of the driven roller, such as applying a load directly to the driven roller, and capable of stable paper transport. There is an effect that it can be provided.

  Further, the sheet conveying apparatus according to the present invention is characterized in that the regulating member urges at least a substantially central portion of the driven roller shaft.

  In the conventional paper conveying apparatus, the restriction member is provided at the substantially central portion of the driven roller shaft where the driven roller is most bent in the paper conveying direction, thereby efficiently preventing the driven roller from being bent in the paper conveying direction. It is possible to do this.

  In the sheet conveying apparatus according to the present invention, a load unit for loading the driven roller in the direction of the driving roller is provided in the middle of the driven roller adjacent to the driven roller provided on the driven roller shaft. It is characterized by being.

  As a result, the sheet conveying apparatus of the present invention is provided with a load means in the direction of the drive roller of the driven roller in the middle of the adjacent driven rollers, so that the load is applied at both ends of the driven roller shaft. In comparison, it is possible to reduce the bending in the load direction.

  Further, the sheet conveying apparatus according to the present invention is characterized in that the bearing supporting the driven roller shaft is a sliding bearing.

  When the bearing that supports the driven roller shaft is a sliding bearing, the load torque on the driven roller shaft is larger than that of the rolling bearing, and the force acting in the bending direction is increased. The increase in the load torque not only makes it difficult for the sheet conveying apparatus to stably convey the sheet, but also causes a decrease in durability and the like.

  Therefore, the provision of the regulating member produces an effect that the effect can be particularly exerted in the sheet conveying device provided with the sliding bearing.

  The sheet conveying apparatus according to the present invention is characterized in that the sheet is conveyed on one side.

  In a paper transport apparatus of a type that transports paper on a one-sided basis, paper meandering and paper jams are noticeable when transporting small-size paper such as postcards. For this reason, the provision of the regulating member can exert an effect particularly in this one-side reference sheet conveying apparatus.

  In addition, since the image forming apparatus of the present invention includes any one of the above-described sheet conveying apparatuses, the oblique image due to the meandering of the sheet and the paper jam in the image forming apparatus are solved.

  Therefore, there is an effect that it is possible to provide an image forming apparatus capable of stably transporting paper.

  As described above, the sheet conveying apparatus according to the present invention includes a regulating member that regulates the movement of the driven roller in the sheet conveying direction in the sheet conveying apparatus including the driving roller and the driven roller for conveying the sheet. It is characterized by having.

  By providing the above configuration, it is possible to prevent the driven roller from moving in the sheet conveying direction, that is, bending, which has been a problem in the sheet conveying apparatus including the driving roller and the driven roller driven by the driving roller.

  Therefore, it is possible to prevent paper meandering and paper clogging caused by a decrease in the conveying force of the driven roller due to bending of the driven roller in the paper conveying direction, and paper conveyance capable of stable paper conveyance. There exists an effect that an apparatus can be provided.

  An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram showing a paper conveying apparatus of the present invention. The sheet conveying apparatus 1 is provided in, for example, an electrophotographic image forming apparatus, and conveys sheets from a sheet feeding apparatus to an output tray after performing image formation and fixing processing. Therefore, the sheet conveying apparatus 1 includes a driving roller 2 (2a to 2d), a driving roller shaft 3, a driven roller 4 (4a to 4d), a driven roller shaft 5, and a torsion coil spring (load means) 6 (6a and 6b for pressure contact). ), A regulating leaf spring (regulating member) 7 and a driven roller bearing (not shown).

  The drive rollers 2a to 2d have the drive roller shaft 3 as an axis, receive a current output from a drive circuit (not shown), and rotate in the direction of arrow R1 (see FIG. 2). In the present embodiment, the driving rollers 2a to 2d are in pressure contact with the driven rollers 4a to 4d. Therefore, the driven rollers 4a to 4d are driven by the rotation of the driving rollers 2a to 2d. The drive rollers 2a to 2d may be made of a material having a high friction coefficient such as rubber. The outer diameters of the drive rollers 2a to 2d are appropriately set depending on the size of the image forming apparatus in which the sheet conveying device is installed and the structure of the image forming apparatus.

  In the present embodiment, a paper conveying apparatus having a configuration in which the driving rollers 2a to 2d and the driven rollers 4a to 4d are in pressure contact with each other is described. Therefore, the driven rollers 4a to 4d can be driven simultaneously with the rotation of the driving rollers 2a to 2d. However, the present invention is not limited to this, as long as the driving rollers 2a to 2d are rotated and the driven rollers 4a to 4d can be driven to drive the driven rollers 4a to 4d. The roller 2a-2d and the driven roller 4a-4d may be in the state which is not press-contacting. For example, a structure in which the driven roller shaft 5 is driven by the rotation of the driving roller shaft 3 by being connected to the driving roller shaft 3 and the driven roller shaft 5 with a roller or a gear mechanism, respectively. You may prepare. Moreover, when connecting with the said roller or a gear mechanism etc., the structure which interlock | cooperates both roller shafts via connecting means, such as a belt mechanism, may be provided.

  The drive roller shaft 3 includes the drive rollers 2a to 2d as described above, and the drive roller bearings are provided at both ends thereof.

  The driven rollers 4a to 4d have the driven roller shaft 5 as an axis, and receive the rotation of the driving rollers 2a to 2d as described above and are driven to rotate in the direction of the arrow R2 (see FIG. 2). The material of the driven rollers 4a to 4d may be rubber, resin, metal or the like. The outer diameters of the driven rollers 4a to 4d are appropriately set depending on the size of the image forming apparatus in which the sheet conveying device is installed and the structure of the image forming apparatus.

  The driven roller shaft 5 supports the driven rollers 4a to 4d as described above, and the driven roller bearings are provided at both ends thereof.

  The number of the driven rollers 4 and the driving rollers 2 is four in the present embodiment. However, the present invention is not limited to this, and the size of the paper conveying device or the paper conveying device is not limited thereto. Is appropriately set depending on the size of the image forming apparatus including

  The press-contact torsion coil springs 6 a and 6 b are provided such that their tips abut against the driven roller shaft 5. Specifically, as shown in FIG. 1, the torsion coil spring 6a for pressure contact has a contact surface on the driven roller shaft 5 between the driven rollers 4a and 4b and to the axis of the drive roller shaft 3. It is provided so that it may contact | abut so that it can load vertically toward it. Similarly, the torsion coil spring 6b for pressure contact is provided so as to come into contact with the driven roller shaft 5 in the middle of the driven rollers 4c and 4d so that a load can be applied vertically toward the axis of the drive roller shaft 3.

  As described above, the torsion coil springs 6a and 6b for pressure contact are loaded in the axial direction of the drive roller shaft 3 (F direction in FIG. 1). When the sheet conveying device 1 is operated to convey a sheet by applying a load in the F direction, the driven rollers 4a to 4d and the driven roller shaft 5 bend in a direction opposite to the F direction, and the meandering of the sheet or the paper Clogging can be prevented.

  It should be noted that a plurality of the torsion coil springs 6a and 6b for pressure contact are preferably brought into contact with each other, and are provided at two locations in the present embodiment, but the number is not limited to this. Further, as the contact position, it is preferable that the contact position is closer to the center portion than both ends of the driven roller shaft 5. This is because the sheet conveying device generally tends to bend the central portion of the driven roller shaft in the longitudinal direction mainly away from the driving roller, that is, in the direction opposite to the F direction.

  The regulating leaf spring 7 will be described with reference to FIG. FIG. 2 is a cross-sectional view illustrating a configuration of a main part of the sheet conveying device 1 of FIG. The tip of the regulating plate spring 7 is urged against the driven roller shaft 5. Since the regulating plate spring 7 biases the driven roller shaft 5, the spring force of the regulating plate spring 7 is not directly applied to the driven roller 4, so that even if the regulating plate spring 7 is provided, the original driven The function of the roller 4 is not hindered. By providing the regulating leaf spring 7, the driven rollers 4a to 4d and the driven roller shaft 5 are prevented from being bent in the sheet conveying direction. Specifically, as shown in FIG. 2, the regulating leaf spring 7 prevents bending in the sheet conveying direction by applying a spring force in the direction of the arrow S. Further, as shown in FIG. 1, the regulating leaf spring 7 is preferably provided so as to be in contact with a central portion in the longitudinal direction of the driven roller shaft 5. The reason is that the center portion of the driven roller shaft 5 in the longitudinal direction is most easily bent by the driven roller shaft 5.

  Further, the regulating member according to the present invention is preferably a leaf spring having a bending spring structure having elasticity like the regulating leaf spring 7. That is, by making the regulating member a bent spring structure, the paper conveying device of the present invention has a small occupation range even when the regulating member is provided, so the size of the conventional paper conveying device is reduced. There is no need to change. In the present embodiment shown in FIG. 2, a substantially U-shaped bending spring structure is formed. Other bent spring structures may be a dogleg shape, an S shape, or the like. By having a bent spring structure, a Young's modulus can be reduced to produce a leaf spring having the same spring constant. Thereby, manufacturing errors in dimensions and shapes are allowed, and the spring constant can be easily set to a target value.

  The material of the regulating leaf spring 7 may be any material that is a leaf spring and is suitable for processing into a bent spring structure. Metal such as stainless steel or copper alloy is preferable, and stainless steel is more preferable. preferable. The thickness of the regulating leaf spring 7 is appropriately set depending on the size of the driven rollers 4a to 4d and the driven roller shaft 5, and is a stainless steel plate having a thickness of 0.2 mm in the embodiments described later.

  Therefore, the sheet conveying apparatus of the present invention can prevent the driven rollers 4a to 4d and the driven roller shaft 5 from being bent in the sheet conveying direction only by providing the regulating plate spring 7 as described above. That is, the paper transport apparatus of the present invention can manufacture the paper transport apparatus of the present invention that enables stable paper transport without greatly changing the manufacturing process of the conventional paper transport apparatus.

  Further, the contact position of the regulating leaf spring 7 will be described. As shown in FIG. 3, the contact surface of the regulating leaf spring 7 with the driven roller shaft 5 is a surface formed by the shaft center of the driven roller shaft 5 and the shaft center of the drive roller shaft 3. 8, a position substantially parallel to the paper carry-out side is θ = 0 °, and from this position, immediately before θ = 90 ° with the rotation direction of the driven roller 4 (direction R2) as the positive direction of the angle. It is preferable that it is contact | abutting between.

  Here, “becoming 90 °” means being perpendicular to the plane 8. The fact that it is perpendicular to the surface 8 overlaps with the effect obtained by the torsion coil springs 6a and 6b for pressure contact, and when there is only a force of a vertical component, it is in the paper conveyance direction by the regulating leaf spring 7. Therefore, the effect of the restricting leaf spring 7 is lost. The contact surface of the regulating leaf spring 7 is preferably in a range from a position substantially parallel to the surface 8 to immediately before 90 ° in the R2 direction. That is, it is preferable that the contact surface of the regulating leaf spring 7 is in contact with the angle θ in FIG. 3 at 0 ° ≦ θ <90 °.

  4 is a position where the contact position of the regulating leaf spring 7 is on the paper carry-out side with respect to the surface 8 but is substantially parallel to the surface 8 in contrast to FIG. From (θ = 0 °), it is in contact with the driven roller shaft 5 at a position (−90 ° <θ <0 °) up to 90 ° in the direction opposite to the R2 direction. That is, the restricting leaf spring 7 is in contact with the driven roller shaft 5 at a position other than the preferred range of the restricting leaf spring 7 shown in FIG. In this case, the driven roller 4 is bent in the direction opposite to the sheet conveying direction by the regulating plate spring 7, the pressure contact force is weakened, and the regulating plate spring 7 cannot exert the intended effect, on the contrary. This will adversely affect the meandering of the paper.

  Furthermore, the sheet conveying device generally tends to bend the central portion of the driven roller shaft 5 in the longitudinal direction mainly in the sheet conveying direction. Therefore, it is preferable that the regulating leaf spring 7 is brought into contact with the approximate center in the longitudinal direction of the driven roller shaft 5.

  In the present embodiment, the restricting leaf spring 7 has been described with respect to the sheet conveying device provided only at one place. However, the present invention is not limited to this, and a plurality of the restricting leaf springs are provided. It may be provided.

  Further, in the present embodiment, the installation location of the regulating leaf spring 7 is shown as being provided on the paper carry-out side. However, the present invention is not limited to this, and as long as the load in a preferable direction as described above is applied, the installation position of the regulating leaf spring 7 is on the paper carry-in side with respect to the surface 8. It may be installed in.

  Next, a driven roller bearing (not shown) will be described. Generally, there are a rolling bearing and a sliding bearing as the bearing of the driven roller shaft. The paper conveying apparatus according to the present invention may be the rolling bearing or the sliding bearing. However, the sliding bearing has a larger load torque on the shaft than the rolling bearing. Therefore, when a sliding bearing is used as a driven roller bearing in a conventional paper transport device, the force acting on the shaft in the direction of deflection becomes larger because the load torque on the shaft is larger than that of the rolling bearing. Therefore, by providing the regulating leaf spring 7 according to the present invention, the sheet conveying device in which the sliding roller bearing is used as the driven roller bearing can effectively reduce the deflection of the shaft.

  In addition, the sheet conveying apparatus according to the present invention may be a sheet conveying apparatus that conveys a sheet on a one-side basis or a sheet conveying apparatus that conveys a sheet on a center basis. However, in the type in which the paper is transported on the basis of one side, the meandering of the paper and the paper jam appear remarkably when the paper of a small size such as a postcard is transported. Therefore, the regulation leaf spring 7 can be particularly effective by being provided in this type of sheet conveying device.

  Next, an image forming apparatus provided with the above-described sheet conveying device will be described with reference to FIG. FIG. 5 shows a digital copying machine 30 to which the paper conveying apparatus of the present invention is applied.

  The main body of the digital copying machine 30 is roughly composed of a scanner unit 31 and a laser recording unit 32.

  The scanner unit 31 includes a document table 35, a double-sided automatic document feeder (RADF) 36, and a scanner unit 40. The double-sided automatic document feeder 36 includes a single-sided document conveyance path, a double-sided document conveyance path, a conveyance path switching unit, a sensor group, and a control unit. The scanner unit 40 includes a first scanning unit 40a, a second scanning unit 40b, a lamp reflector assembly 41, a first reflecting mirror 42a, a second reflecting mirror 42b, a third reflecting mirror 42c, an optical lens 43, and a CCD element 44. I have.

  The laser recording unit 32 includes a laser writing unit 46, an electrophotographic process unit 47, and a paper conveyance system. The laser writing unit 46 further includes a semiconductor laser light source, a polygon mirror, an f-θ lens, and the like. The electrophotographic process unit 47 further includes a photosensitive drum 48 and a charger, a developing device, a transfer device, a peeling device, a cleaning device, and a static eliminator around the photosensitive drum 48. The paper transport system further includes a transport unit 33, a fixing device 49, cassette paper feeders 51, 52, and 53, a manual paper feeder 54, a refeed path 55, a post-processing device, and a paper discharge roller (paper transport device). 57).

  The double-sided automatic document feeder 36 sets a plurality of documents at once on a document tray (not shown) provided, and automatically sets the set documents one by one on the document placement table 35 of the scanner unit 40. It is a device that feeds up. The document table 35 is made of transparent glass. As described above, the double-sided automatic document feeder 36 includes the single-sided document conveyance path, the double-sided document conveyance path, and the conveyance path switching means. The sensor group grasps the state of the document passing through these parts. to manage. The control unit causes the scanner unit 40 to read one or both sides of the document according to the operator's selection.

  The scanner unit 40 is a document image reading unit for scanning and reading an image of a document placed on the document placement table 35. A lamp reflector assembly 41 provided in the scanner unit 40 is provided for exposing the document surface. Similarly, the first scanning unit 40a is equipped with a first reflection mirror 42a for reflecting the reflected light from the document for guiding the reflected light image from the document to the photoelectric conversion element (CCD element 44), and the second scanning unit 40b. Are mounted with second and third reflection mirrors 42b and 42c for guiding the reflected light image from the first reflection mirror unit 40a to the photoelectric conversion element (CCD element 44). The optical lens 43 forms an image of the reflected light from the original on an element (CCD element 44) that converts the image of the reflected light into an electrical image signal via the reflection mirrors described above. The CCD element 44 converts the reflected light image from the document into an electrical image signal.

  The scanner unit 31 scans along the lower surface of the document placing table 35 while sequentially placing the documents to be read on the document placing table 35 by operations related to the automatic document feeder 36 and the scanner unit 40. The unit 40 is moved to read the original image.

  In particular, the first scanning unit 40a travels from the left to the right along the document placement table at a constant speed V, and the second scanning unit 40b is parallel to the speed V at a speed of V / 2 in the same direction. The scanning is controlled. As a result, the image of the document placed on the document placement table 35 is sequentially formed on the CCD element 44 for each line, and the image is read.

  Image data obtained by reading a document image with the scanner unit 40 is sent to an image processing unit to be described later, subjected to various processes, temporarily stored in the memory of the image processing unit, and according to an output instruction. The image in the memory is read out and transferred to the laser recording unit 32 to form an image on the paper.

  The semiconductor laser light source provided in the laser writing unit 46 emits laser light in accordance with image data read from the memory after being read by the scanner unit 40 or image data transferred from an external device. To do. Similarly, the polygon mirror deflects laser light at an equal angular velocity. The f-θ lens corrects the laser light deflected at a constant angular velocity so that it is deflected at a constant velocity on the photosensitive drum constituting the electrophotographic process unit 47.

  The charger provided in the electrophotographic process unit 47 uniformly charges the surface of the photosensitive drum 48 according to image data. The charger may be a contact brush type, a roller type, or a non-contact charger type. The static eliminator irradiates the photosensitive drum 48 with light to remove residual charges. The developing device visualizes the electrostatic latent image formed on the surface of the photosensitive drum 48 using a powder developer (toner). The transfer unit transfers the toner image visualized on the photosensitive drum 48 onto the sheet. The stripper is a stripping unit that strips the sheet on which the toner image is transferred from the photosensitive drum 48 by, for example, AC corona discharge. The cleaning device is a cleaning unit that scrapes off the toner remaining on the photosensitive drum 48 after the transfer of the toner image.

  The cassette paper feeding devices 51, 52, 53 provided in the paper transport system or the manual paper feeding device 54 for appropriately feeding sheets of a necessary size are used in the electrophotographic process unit 47 that performs the above-described image formation. In particular, the sheet is conveyed to a transfer position where the transfer unit is disposed. The fixing device 49 fixes an image, particularly a toner image, formed on a sheet by the transfer device. The re-feeding path 55 re-feeds the sheet in order to form an image again on the back surface of the fixed sheet P. A post-processing device that receives a sheet on which an image is recorded and performs a predetermined process on the sheet is disposed downstream of the fixing unit 49, and the sheet on which the fixing of the image has been completed by the fixing unit 49. Is conveyed into the post-processing device 34.

  In the digital copying machine 30 configured as described above, the printing process is performed as follows. When the scanned image data is input to the scanner unit 40, the paper is separated one by one by the pickup roller 60 provided at the end of the cassette paper feeder 51, 52, 53 or the manual paper feeder 54. And send it out to the paper transport path. Thereafter, the sheet is conveyed to a registration roller (not shown), and the conveyance of the sheet is temporarily stopped in a state where the leading end of the sheet reaches the registration roller.

  In parallel with the paper feeding from the paper feeding device, the electrophotographic process unit 47 starts forming a toner image based on the input image data. That is, when image data is input to the digital copying machine 30, the surface of the photosensitive drum 48 is charged by the charger. Thereafter, an electrostatic latent image is formed on the surface of the photosensitive drum 48 charged by the laser beam irradiation from the laser writing unit 46 according to the input image data. In order to develop the electrostatic latent image, toner is supplied from a developing device to form a toner image. Next, the formed toner image and the sheet pass between the transfer units, whereby the toner image formed on the photosensitive drum 48 is transferred onto the sheet. In the case of forming an image with multi-color toner, the electrophotographic process unit 47 corresponds to each color (black, cyan, magenta, yellow), and the toner images of the respective colors are sequentially stacked on the sheet. A multicolor toner image is formed.

  Thereafter, when fixing of the toner image on the paper is completed by the fixing device 49, the paper is conveyed into the post-processing device 34. Finally, the paper is discharged onto the paper discharge tray 341 or the paper discharge tray 342.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example and a comparative example, this invention is not limited to this.

  The sheet conveying apparatus described in this embodiment has the same configuration as the sheet conveying apparatus 1 shown in FIG. 1 described above, and includes driving rollers 2a to 2d, driving roller shaft 3, driven rollers 4a to 4d, driven roller shaft 5, and pressure contact. Torsion coil springs 6a and 6b, a regulating leaf spring (regulating member) 7, and a driven roller bearing and a driving roller bearing (not shown).

  The drive rollers 2a to 2d have the drive roller shaft 3 as an axis, receive a driving force from a driving means (not shown), and rotate in the direction of an arrow R1 (see FIG. 2). The driving rollers 2a to 2d are in pressure contact with the driven rollers 4a to 4d, and the driven rollers 4a to 4d are also driven by the rotation of the driving rollers 2a to 2d.

  As the driving rollers 2a to 2d, rubber rollers having an outer diameter of 12 mm were used. The drive roller shaft 3 includes the drive rollers 2a to 2d as described above, and the drive roller bearings are provided at both ends. The drive roller shaft 3 was a stainless steel shaft having a diameter of 6 mm.

  The driven roller 4 has the driven roller shaft 5 as an axis, receives the rotation of the driving rollers 2a to 2d as described above, and is driven to rotate in the direction of the arrow R2 (see FIG. 2). As the driven rollers 4a to 4d, resin rollers having an outer diameter of 6 mm were used.

  The driven roller shaft 5 includes the driven rollers 4a to 4d as described above, and the driven roller bearings are provided at both ends thereof. The driven roller shaft 5 was a 4 mm stainless steel shaft.

  The press-contact torsion coil springs 6 a and 6 b are provided such that their tips abut against the driven roller shaft 5. Specifically, as shown in FIG. 1, the torsion coil spring 6a for pressure contact is provided so as to contact the driven roller shaft 5 between the driven rollers 4a and 4b, and the torsion coil spring 6b for pressure contact is It was provided so as to contact the driven roller shaft 5 between the driven rollers 4c and 4d. The torsion coil springs 6a and 6b for pressure contact are arranged so that the driven roller shaft 5 is perpendicular to the axial direction of the driving rollers 2a to 2d and the driving roller shaft 3 provided with the driven roller shaft 5 (F direction in the figure). To load.

  The regulating leaf spring 7 will be described with reference to FIG. FIG. 2 is an enlarged cross-sectional view of the sheet conveying apparatus 1 of FIG. As shown in FIG. 1, the regulating plate spring 7 is provided so that its tip abuts on the driven roller shaft 5 between the driven rollers 4b and 4c. Specifically, the contact surface of the regulating plate spring 7 with the driven roller shaft 5 is a surface 8 formed by the shaft center of the driven roller shaft 5 and the shaft center of the drive roller shaft 3. It was substantially parallel to the surface 8 and abutted against the surface 8 at a position on the paper discharge side. Stainless steel was used as the material of the regulating leaf spring 7. The thickness of the regulating leaf spring 7 was 0.2T.

[Comparative example]
Instead of the sheet conveying apparatus 1 having the configuration described in the embodiment, a sheet conveying apparatus that does not include the regulating leaf spring is used. The configuration other than the regulation leaf spring is the same as that of the sheet conveying apparatus 1 described in the embodiment.

  Using the sheet conveying device having the above-described configuration, the roller pressing force of each of the driven rollers 4a to 4d was measured. Specifically, it is as follows.

  As described above, by using the sheet conveying device having each configuration, the torsion coil spring 6a for pressure contact provided to contact the driven roller shaft 5 between the driven rollers 4a and 4b, and the driven roller 4c. And a torsion coil spring 6b for pressure contact provided so as to come into contact with the driven roller shaft 5 between 4d and 4d, a load of the same magnitude is driven on the driven roller shaft 5 in a direction perpendicular to the axial direction of the drive roller shaft 3. The roller pressing force of each of the driven rollers 4a to 4d was measured in the direction approaching the roller shaft 3 (the F direction in FIG. 1). The results are shown in the following table.

  As shown in the table, it can be seen that the roller conveying force of each of the driven rollers 4a to 4d in the sheet conveying device 1 shown in the embodiment provided with the regulating leaf springs is all uniform. On the other hand, the sheet conveying apparatus shown in the comparative example not provided with the regulating leaf spring has the driven rollers 4a to 4d, and the driven rollers 4a and 4d located at both ends of the driven roller shaft 5 and the coaxial center side. It can be seen that the pressure contact forces with the driven rollers 4b and 4c located are different. That is, since the pressure contact force with the driven rollers 4b and 4c located on the center side of the driven roller shaft 5 is lower than that of the driven rollers 4a and 4d located at both ends of the coaxial, the sheet conveying device in the comparative example is a driven roller. It turns out that it has bent in the center side of the axis | shaft.

  From this, it is apparent that the sheet conveying apparatus of the present invention provided with the regulating leaf spring (regulating member) is more clearly compared with the sheet conveying apparatus not provided with the regulating leaf spring. Can be prevented.

  The paper conveying apparatus of the present invention can prevent the driven roller from being bent by providing the regulating member. Therefore, in the paper transport device of the present invention, the driven roller does not bend even when various types of paper having different sizes and thicknesses are used. Therefore, unlike the prior art, there is no occurrence of slanting due to meandering of the transported paper or paper jam due to delay in transport.

  Therefore, the image forming apparatus provided with the paper conveyance device of the present invention enables smooth printing without any problem in paper conveyance even when various types of paper having different sizes and thicknesses are used. Therefore, the paper conveying apparatus of the present invention can be applied to any image forming apparatus.

1 illustrates an embodiment of the present invention and is a diagram illustrating a configuration of a sheet conveying device. FIG. 1 is a cross-sectional view illustrating a configuration of a main part of a sheet conveying apparatus according to an embodiment of the present invention. FIG. 5 is a cross-sectional view illustrating another embodiment of the present invention and illustrating a configuration of a main part of a sheet conveying device. FIG. 4 is a sheet conveying apparatus shown as a comparison with the sheet conveying apparatus shown in FIG. 3. FIG. 1 is a schematic configuration diagram illustrating an image forming apparatus including a sheet conveying device of the present invention. (A) And (b) is a figure which shows a prior art and shows the structure of a paper conveying apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Paper conveying apparatus 2 (2a-2d) Drive roller 3 Drive roller shaft 4 (4a-4d) Driven roller 5 Driven roller shaft 6 (6a, 6b) Torsion coil spring for pressure contact (load means)
7 Regulation leaf spring (regulation member)
8 sides 30 Digital copier (image forming device)
Reference Signs List 31 Scanner Unit 32 Laser Recording Unit 33 Conveying Unit 34 Post-Processing Device 35 Document Placement Table 36 Double Sided Automatic Document Feeder (RADF)
40 Scanner unit 40a First scanning unit 40b Second scanning unit 41 Lamp reflector assembly 42a First reflecting mirror 42b Second reflecting mirror 42c Third reflecting mirror 43 Optical lens 44 CCD element 46 Laser writing unit 47 Electrophotographic process section 48 Photoconductor Drum 49 Fixing device 51, 52, 53 Cassette paper feeder 54 Manual paper feeder 55 Refeed path 57 Paper discharge roller 100 Paper transport device 101 in the prior art (driven paper transport device in the prior art) Driven roller 102 (conventional technology) Drive rollers 341 and 342 in the paper transport device

Claims (11)

In a paper transport device having a driving roller and a driven roller for transporting paper,
A sheet conveying apparatus comprising a regulating member for regulating movement of the driven roller in the sheet conveying direction.   The sheet conveying apparatus according to claim 1, wherein the regulating member has elasticity.   The predetermined surface of the restricting member is substantially parallel to a surface formed by the axis of the driven roller shaft and the shaft center of the driving roller shaft that supports the driving roller, and the sheet is in the surface Contacted with the driven roller shaft at a position on the discharge side, or contacted with the driven roller shaft between the position and a position rotated by less than 90 ° in the rotational direction of the driven roller. The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus.   The sheet conveying device according to claim 1, wherein the regulating member is a leaf spring.   The sheet conveying device according to claim 4, wherein the leaf spring is a bending spring.   6. The sheet conveying device according to claim 1, wherein the restricting member biases a driven roller shaft that supports the driven roller. 7.   The sheet conveying device according to claim 6, wherein the regulating member biases at least a substantially central portion of the driven roller shaft.   The load means for loading the driven roller in the direction of the driving roller is provided in the middle of the driven rollers adjacent to each other of the driven rollers provided on the driven roller shaft. The sheet conveying apparatus according to any one of the above.   9. The paper conveying apparatus according to claim 1, wherein the bearing that supports the driven roller shaft is a sliding bearing.   The paper transport apparatus according to claim 1, wherein the paper is transported on a one-side basis.   An image forming apparatus comprising the sheet conveying device according to claim 1.

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