JP2015209945A - Torque adjustment mechanism of revolving shaft, and paper conveying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a torque adjustment mechanism of revolving shaft capable of adding a certain degree of torque to a revolving shaft and adjusting properly a torque of the revolving shaft also at the time of high temperature.SOLUTION: A torque adjustment mechanism 41 of a revolving shaft 32 is the torque adjustment mechanism 41 of the revolving shaft 32 to adjust a torque of the revolving shaft 32 and this mechanism comprises an intermediate member 42 made of resin that is arranged at an outer diameter side of the revolving shaft 32, fixed to the revolving shaft 32 and rotated together with the revolving shaft 32; a metallic angle spring 46 in which the intermediate member 42 is arranged in its inner side; and motion restricting means for restricting motion of the angle spring 46 to at least one of the end parts 47a, 47b. At a temperature less than the first temperature, the intermediate member 42 is slid in respect to the angle spring 46 and at a temperature more than the first temperature, an outer diameter surface 45 of the intermediate member 42 presses against the inner diameter surface 48 of the angle spring 46 due to thermal expansion.

Description

  The present invention relates to a torque adjusting mechanism for a rotating shaft (hereinafter sometimes simply referred to as “torque adjusting mechanism”) and a sheet conveying apparatus.

  An image processing apparatus typified by a digital multi-function peripheral is provided with a sheet conveying apparatus that conveys a sheet to be printed together with an image forming unit that forms an image. The paper transport device includes a motor that is a drive source for transporting paper, a plurality of transport rollers that transport the paper in contact with the paper, and a clutch that matches the transport timing of the paper. The motor rotates the transport roller via the rotation shaft, and transports the paper by the rotation of the transport roller. The clutch transmits power from the motor to the rotating shaft by connection, and interrupts transmission of power to the rotating shaft by releasing. The clutch estimates the timing and transmits the power from the motor to the rotating shaft, and conveys the sheet to the image forming unit at an appropriate timing.

  Here, the technique regarding the spring clutch using a spring is disclosed by Unexamined-Japanese-Patent No. 2005-321045 (patent document 1). According to Patent Document 1, in the spring clutch, a diameter expansion limiting means is provided on the free end side of the coil spring, thereby providing a limiter function for idling the outer ring during high load torque.

Japanese Patent Laid-Open No. 2005-321045

  When the clutch is driven at a high frequency, the temperature of the clutch and its surroundings rises due to heat generation. As a result, the temperature rises as a factor, and the torque for rotating the rotating shaft increases excessively. As a result, the life of the clutch may be shortened, and the clutch engagement time and release time may vary.

  Here, a torque limiter mechanism that idles the rotating shaft as shown in Patent Document 1 may be provided in preparation for a case where a certain amount or more of torque is applied to the rotating shaft. However, even with such a torque limiter, there is a possibility that the above problem due to temperature rise cannot be solved.

  Further, in order to drive the clutch stably, it is necessary to apply a certain amount of torque to the clutch. That is, it is necessary to adjust the torque within a certain range. In many cases, a brake is provided in order to generate a certain amount of torque. However, even with this brake, heat is likely to be generated.

  An object of the present invention is to provide a torque adjusting mechanism for a rotating shaft that can add a certain amount of torque to the rotating shaft and can appropriately adjust the torque of the rotating shaft even at high temperatures.

  Another object of the present invention is to provide a paper transport device that can transport paper more accurately.

  The torque adjusting mechanism for the rotating shaft according to the present invention is a torque adjusting mechanism for the rotating shaft that adjusts the torque of the rotating shaft, and is disposed on the rotating shaft and the outer diameter side of the rotating shaft, and is fixed to the rotating shaft. An intermediate member made of resin that rotates together with the rotating shaft, a metal coil spring in which the intermediate member is disposed on the inner side thereof, and a movement restricting means that restricts movement of at least one end of the coil spring. Prepare. Below the first temperature, the intermediate member slides relative to the coil spring, and above the first temperature, the outer diameter surface of the intermediate member presses the inner diameter surface of the coil spring due to thermal expansion.

  According to such a torque adjustment mechanism of the rotating shaft, since the movement of at least one end of the coil spring is restricted, the intermediate member and the coil spring that rotate together with the rotating shaft if the temperature is lower than the first temperature. And a certain amount of torque can be applied to the rotating shaft. Moreover, if it is more than 1st temperature, the outer-diameter surface of resin-made intermediate members will press the inner-diameter surface of a coil spring by thermal expansion, and will try to rotate a coil spring. In this case, since the movement of at least one end of the coil spring is restricted, the torque can be increased or the torque can be decreased according to the winding direction, the amount of twist, and the tightening force of the coil spring. Therefore, according to such a torque adjusting mechanism for the rotating shaft, a certain amount of torque can be applied to the rotating shaft and the torque of the rotating shaft can be adjusted appropriately even at high temperatures.

  In another aspect of the present invention, the paper transport device is disposed on the outer diameter side of the rotary shaft, and is fixed to the rotary shaft. The transport roller transports the paper, the rotary shaft that rotates the transport roller, and the rotary shaft. A resin intermediate member that rotates together with the rotating shaft, a metal coil spring on which the intermediate member is disposed, and a movement that restricts movement of at least one end of the coil spring. The intermediate member slides with respect to the coil spring at a temperature lower than the first temperature, and the outer diameter surface of the intermediate member is increased by thermal expansion at a temperature equal to or higher than the first temperature. Press the inner surface.

  Such a paper transport device can transport paper more accurately.

  According to such a torque adjustment mechanism of the rotating shaft, since the movement of at least one end of the coil spring is restricted, the intermediate member and the coil spring that rotate together with the rotating shaft if the temperature is lower than the first temperature. And a certain amount of torque can be applied to the rotating shaft. Moreover, if it is more than 1st temperature, the outer-diameter surface of resin-made intermediate members will press the inner-diameter surface of a coil spring by thermal expansion, and will try to rotate a coil spring. In this case, since the movement of at least one end of the coil spring is restricted, the torque can be increased or the torque can be decreased according to the winding direction, the amount of twist, and the tightening force of the coil spring. Therefore, according to such a torque adjusting mechanism for the rotating shaft, a certain amount of torque can be applied to the rotating shaft and the torque of the rotating shaft can be adjusted appropriately even at high temperatures.

  Further, such a paper transport device can transport paper more accurately.

1 is a schematic perspective view illustrating an external appearance of a digital multifunction peripheral when an image processing apparatus including a paper conveyance device according to an embodiment of the present invention is applied to the digital multifunction peripheral. 1 is a block diagram illustrating a configuration of a digital multifunction peripheral when an image processing apparatus including a paper transport device according to an embodiment of the present invention is applied to the digital multifunction peripheral. FIG. 3 is an external view illustrating a part of the sheet conveying apparatus. A part of the sheet conveying apparatus shown in FIG. 3 is an external view seen from one side in the axial direction of the rotary shaft to be described later shown in the direction of arrow D ₁ of the in Figure 3. A part of the sheet conveying apparatus shown in FIG. 3 is an external view seen from the other side in the axial direction of the rotating shaft indicated by the arrow D ₁ in the opposite direction in FIG. 3, on one side of the corner spring to be described later end The state which the part moved to the end surface of the one side of a groove part is shown. FIG. 4 is a cross-sectional view of a part of the sheet conveying device shown in FIG. FIG. 4 is a cross-sectional view of a part of the sheet conveying device shown in FIG. 3, and is a cross-sectional view taken along the plane indicated by VII-VII in FIG. It is a perspective view of an intermediate member. It is a perspective view of a coil spring. A part of the sheet conveying apparatus shown in FIG 3 is an external view seen from the other side of axial direction of the rotary axis shown by the arrow D ₁ in the opposite direction in FIG. 3, the end portion of one side of the corner spring The state which moved to the end surface of the other side of a groove part is shown.

  Embodiments of the present invention will be described below. First, the configuration of an image processing apparatus including a paper transport device according to an embodiment of the present invention will be described. FIG. 1 is a schematic perspective view showing an external appearance of a digital multi-function peripheral when an image processing apparatus including a paper transport device according to an embodiment of the present invention is applied to the digital multi-function peripheral. FIG. 2 is a block diagram illustrating a configuration of a digital multifunction peripheral when an image processing apparatus including a sheet conveying device according to an embodiment of the present invention is applied to the digital multifunction peripheral.

  Referring to FIGS. 1 and 2, a digital multifunction peripheral 11 as an image processing apparatus includes a control unit 12 that controls the entire digital multifunction peripheral 11, information transmitted from the digital multifunction peripheral 11, and user input contents. An operation unit 13 including a display screen 21 for displaying, an image forming condition such as the number of copies and gradation, and input of power on / off, and an ADF (Auto Document Feeder) that automatically conveys a set document to a reading unit. ) 22 and includes an image reading unit 14 that reads an image of a document and a developing device 23 that performs development using toner, and forms an image based on the read image and image data transmitted through the network 25. An image forming unit 15; a hard disk 16 as storage means for storing transmitted image data, input image forming conditions, and the like; It is connected to the line 24 and includes a facsimile communication unit 17 for performing facsimile transmission and reception, a network interface unit 18 for connecting to a network 25, and a paper feed cassette 28 for storing a plurality of sheets. A paper transport device 31 that transports the paper on which the visualized image is transferred to the image forming unit 15 or the like. The digital multi-function peripheral 11 includes a DRAM (Dynamic Random Access Memory) for writing and reading image data, and the illustration and description thereof are omitted. In addition, arrows in FIG. 2 indicate the flow of data regarding control signals, control, and images. Note that the control of the paper transport device 31 is also performed by the control unit 12 provided in the digital multi-function peripheral 11.

  The digital multifunction machine 11 operates as a copying machine by forming an image in the image forming unit 15 using the original read by the image reading unit 14. The digital multi-function peripheral 11 forms an image in the image forming unit 15 using the image data transmitted from the computers 26a, 26b, and 26c connected to the network 25 through the network interface unit 18 as a printer. Operate. That is, the image forming unit 15 operates as a printing unit that prints the requested image. Further, the digital multifunction peripheral 11 forms an image in the image forming unit 15 via the DRAM using the image data transmitted from the public line 24 through the facsimile communication unit 17, and also by the image reading unit 14. The image data of the read original is transmitted to the public line 24 through the facsimile communication unit 17, thereby operating as a facsimile apparatus. That is, the digital multifunction peripheral 11 has a plurality of functions such as a copying function, a printer function, and a facsimile function with respect to image processing. Further, each function has functions that can be set in detail.

  The image processing system 27 including the digital multifunction peripheral 11 includes the digital multifunction peripheral 11 and a plurality of computers 26a, 26b, and 26c. Specifically, the image processing system 27 includes the digital multifunction peripheral 11 having the above-described configuration and a plurality of computers 26 a, 26 b, and 26 c connected to the digital multifunction peripheral 11 via the network 25. In this embodiment, three computers 26a to 26c are shown. Each of the computers 26 a to 26 c can print by making a print request to the digital multi-function peripheral 11 via the network 25. The digital multi-function peripheral 11 and the computers 26a to 26c may be connected by wire using a LAN (Local Area Network) cable or the like, or may be connected wirelessly. A configuration in which a digital multifunction peripheral or a server is connected may be used.

Next, the configuration of the paper transport device 31 according to an embodiment of the present invention will be described. FIG. 3 is an external view showing a part of the sheet transport device 31. FIG. 3 corresponds to the case where the sheet conveying device 31 is viewed from the so-called side. Figure 4 is a part of the sheet conveying device 31 shown in FIG. 3 is an external view seen from one side in the axial direction of the rotary shaft to be described later shown in the direction of arrow D ₁ of the in Figure 3. FIG. 4 corresponds to a view of a side plate, which will be described later, as viewed from the conveyance roller side, which will be described later. 5, a portion of the sheet conveying device 31 shown in FIG. 3 is an external view seen from the other side in the axial direction of the rotating shaft indicated by the arrow D ₁ in the opposite direction in FIG. FIG. 5 corresponds to a view of a fixing member, which will be described later, as viewed from the motor side, which will be described later. 6 and 7 are cross-sectional views of a part of the sheet conveying device 31 shown in FIG. 6 is a cross-sectional view taken along the plane indicated by VI-VI in FIG. 3, and FIG. 7 is a cross-sectional view taken along the plane indicated by VII-VII in FIG. The states shown in FIGS. 3 to 7 are so-called normal temperature states, which are lower than a first temperature described later.

1 to 7, a sheet transport device 31 according to an embodiment of the present invention includes a rotating shaft 32, a motor 33 indicated by a two-dot chain line as a driving source for rotating the rotating shaft 32, and a motor 33. The conveyance roller 34 shown with the dashed-two dotted line rotated by the drive of this, the electromagnetic clutch 35 interposed between the motor 33 and the conveyance roller 34, and the paper feed cassette 28 which accommodates several paper are included. The rotating shaft 32 has a round bar shape extending straight, and is made of metal. Note that a part of the rotating shaft 32 is not shown from the viewpoint of easy understanding. The outer diameter of the rotary shaft 32 is indicated by the length L ₁ in FIG. Rotary shaft 32 by a motor 33, rotates in the direction indicated by the arrow _{D 2} in FIG. A rotation center 37 of the rotation shaft 32 is indicated by a one-dot chain line in FIG. The side on which the motor 33 serving as a drive source is disposed is the input side, and the side on which the transport roller 34 is disposed is the output side. Note that a plurality of transport rollers 34 are included in the paper transport device 31 and are provided throughout the digital multifunction peripheral 11.

  The paper transport device 31 sequentially transports the paper stored in the paper feed cassette 28 to the image forming unit 15 in response to a request for image formation. After the image formed in the image forming unit 15 is transferred to the paper, the paper transport device 31 discharges the image to the outside of the digital multi-function peripheral 11, specifically, to the paper discharge section 36 provided in the digital multi-function peripheral 11. Transport the paper. The paper transport device 31 rotates the rotating shaft 32 by driving the motor 33 and rotates the transport roller 34 to transport the paper so as to feed the paper in one direction. The electromagnetic clutch 35 provided between the motor 33 and the rotating shaft 32 connects the motor 33 and the rotating shaft 32 when the power is turned on, that is, when power is supplied to the electromagnetic clutch 35. Is transmitted to the rotating shaft 32. Further, the electromagnetic clutch 35 releases the connection between the motor 33 and the rotating shaft 32 and shuts off the transmission of power to the rotating shaft 32 when the power is turned off, that is, the electric power supplied to the electromagnetic clutch 35 is interrupted. The timing of conveying the sheet to the image forming unit 15 and the like is adjusted by turning on / off the power of the electromagnetic clutch 35.

The paper transport device 31 includes a torque adjustment mechanism 41 of the rotary shaft 32 that adjusts the torque of the rotary shaft 32. The torque adjustment mechanism 41 includes a rotating shaft 32 and an intermediate member 42 that is disposed on the outer diameter side of the rotating shaft 32, is fixed to the rotating shaft 32, and rotates together with the rotating shaft 32. FIG. 8 is a perspective view of the intermediate member 42. Referring to FIG. 8 and the like, the intermediate member 42 has a cylindrical shape having a predetermined thickness. The inner diameter of the intermediate member 42 shown by the length L ₂ is substantially made equal to the outer diameter of the rotary shaft 32 indicated by the length L _1. Incidentally, showing the outer diameter of the intermediate member 42 by a length L _3. Both end faces 43a and 43b of the intermediate member 42 are flat. The longitudinal length of the cylindrical intermediate member 42, the end surface 43a in FIG. 8, represented by the length L ₄ between 43b. The intermediate member 42 is disposed on the outer diameter side of the rotation shaft 32. The intermediate member 42 is fixed to the rotating shaft 32. In this case, the inner diameter surface 44 of the intermediate member 42 is bonded and fixed to a part of the outer diameter surface 38 of the rotating shaft 32 with an adhesive.

The intermediate member 42 is made of resin. Specifically, the material of the intermediate member 42 is POM (Polyoxymethylene). POM is also called polyacetal. The linear expansion coefficient of this POM is 9 × 10 ⁻⁵ / ° C.

The torque adjustment mechanism 41 includes an angular spring 46 that is a kind of coil spring. FIG. 9 is a perspective view of the square spring 46. Referring to FIG. 9 and the like, the square spring 46 is manufactured by bending an elongated rod-like member having a square cross section into a spiral shape so as to have a predetermined inner diameter. Winding direction of the corner spring 46 is a direction indicated by arrow D ₃ in FIG. The inner diameter of the corner spring 46 is represented by a length _{L 5.} The inner diameter of the corner spring 46 shown by the length L ₅ represents, is substantially made equal to the outer diameter of the intermediate member 42 shown by the length L _3.

Both end portions 47 a and 47 b of the angular spring 46 have a shape protruding outward from the angular spring 46. That is, both end portions 47a and 47b do not extend in the winding direction as they are, but are configured to be bent in a direction perpendicular to the winding direction so as to extend in the longitudinal direction. Incidentally, longitudinal length of the corner spring 46 except both end portions 47a, and 47b is represented by a length _{L 6} in FIG.

The square spring 46 is made of metal. Specifically, the material of the square spring 46 is SWP-B. The linear expansion coefficient of SWP-B is 11 × 10 ⁻⁶ / ° C.

  An intermediate member 42 is disposed on the inner side of the square spring 46. Specifically, the cylindrical intermediate member 42 and a part of the rotating shaft 32 are disposed inside the inner diameter surface 48 of the angular spring 46. At normal temperature as the first temperature, the inner diameter surface 48 of the angular spring 46 and the outer diameter surface 45 of the intermediate member 42 are provided so as to come into light contact.

  The torque adjustment mechanism 41 includes a movement restricting means 51 that restricts the movement of both end portions 47 a and 47 b of the angular spring 46. Specifically, the movement restricting means 51 restricts the movement in the circumferential direction that is the winding direction of the both end portions 47 a and 47 b of the angular spring 46. In this case, the movement restricting means 51 includes a side plate 52 and a fixing member 56.

The side plate 52 is a thin flat plate-like member, and constitutes a part of the frame inside the digital multifunction peripheral 11. The side plate 52 is provided with an insertion hole 53 through which the rotary shaft 32 is inserted. Diameter of the insertion hole 53 is substantially made equal to the outer diameter of the rotary shaft 32 indicated by the length L _1. The side plate 52 is provided with an engagement hole 54 that engages one end 47a of the square spring 46. The engagement hole 54 is provided so as to open in a shape that engages with the end 47 a on one side of the square spring 46. That is, it is provided so as to penetrate the side plate 52 so that the outline thereof is a quadrangular shape. By engaging the end 47a on one side of the square spring 46 with the engagement hole 54, the movement of the end 47a in the circumferential direction is restricted. In this case, the movement of the end 47a in the radial direction is also restricted.

The fixing member 56 is a member obtained by bending a flat plate-like member so that the cross section has a U-shape when viewed from above. That is, the fixing member 56 has a shape in which three flat plate members 57a, 57b, and 57c are joined to each other so as to be perpendicular to each other. An insertion hole 58 through which the rotary shaft 32 is inserted is provided in the central region of the flat plate member 57b located in the center of the fixed member 56. For even the diameter of the insertion hole 58, and is substantially made equal to the outer diameter of the rotary shaft 32 indicated by the length L _1. Of the flat members 57a and 57c, the end portions 59a and 59c on the side not connected to the flat member 57b are perpendicular to the direction opposite to the side where the flat member 57b is located for mounting the fixing member 56, respectively. Is bent.

The fixing member 56 is provided with a groove portion 61 that engages with the other end portion 47 b of the square spring 46. The groove 61 is provided in a flat plate member 57 b located in the center of the fixed member 56. Specifically, the groove 61 has a shape that engages with the other end 47b of the angular spring 46, that is, the through hole so that the outline thereof is a quadrangle, and the angular spring It is provided so as to open in an arc shape with the inner diameter of 46 as a radius. Angle A ₁ of the other side in the circumferential direction of the end face 62b on one side in the circumferential direction of the end surface 62a and the groove 61 of the groove 61 provided in a circular arc shape is approximately about 45 degrees. As for the engagement between the groove portion 61 and the end portion 47b, the end portion 47b engaged with the groove portion 61 is fitted and engaged so as not to move in the circumferential direction unless a certain amount of torque is applied. The end portion 47 b is restricted from moving in the circumferential direction between the end surfaces 62 a and 62 b of the groove portion 61. That is, the circumferential range in which the end portion 47 b can move is between the end surfaces 62 a and 62 b of the groove portion 61. Further, the end portion 47 b is also restricted from moving in the radial direction by the groove portion 61.

  The fixing member 56 is attached to the side plate 52 by fixing the end portions 59a, 59c of the two flat plate members 57a, 57c bent vertically to the side plate 52. In this case, it is attached so that the position of the insertion hole 58 provided in the flat plate member 57 b faces the insertion hole 53 provided in the side plate 52. Attachment to the side plate 52 is performed using screws, bolts or the like (not shown). In this case, in the state seen from the upper side shown in FIG. 3, the side plate 52 and the flat plate member 57b are attached so as to be approximately parallel.

  The rotary shaft 32 is attached to the paper transport device 31 so as to pass through the insertion hole 53 provided in the side plate 52 and the insertion hole 58 provided in the flat plate member 57 b of the fixing member 56. The intermediate member 42 fixed to the rotating shaft 32 is disposed on the inner side of the fixing member 56, specifically, in a region surrounded by the flat plate members 57 a to 57 c and the side plate 52. The angular spring 46 is also disposed in a region surrounded by the flat plate members 57 a to 57 c and the side plate 52. The angular spring 46 is disposed on the outer diameter side of the intermediate member 42. The square spring 46 has one end 47a engaged with an engagement hole 54 provided in the side plate 52, and the other end 47b engaged with a groove 61 provided in the flat plate member 57b. It is attached. The outer diameter surface 49 of the square spring 46 and the flat plate members 57a and 57c are not in contact with each other, and are provided at an interval.

  Here, the torque adjustment mechanism 41 is configured such that the intermediate member 42 slides with respect to the angular spring 46 below the first temperature. Further, the torque adjusting mechanism 41 is configured such that the outer diameter surface 45 of the intermediate member 42 presses the inner diameter surface 48 of the angular spring 46 by thermal expansion above the first temperature.

Next, a description will be given of a case where the torque is increased and adjusted at a high temperature. First, a case where the temperature is lower than the first temperature, for example, a room temperature of about 25 ° C. will be described. Referring to FIG. 7 or the like, the rotation in the case of less than the first temperature, the electromagnetic clutch 35 is turned on, power from the motor 33 is transmitted to the rotation shaft 32, the rotary shaft 32 in the direction of arrow D ₂ Then, according to this, the intermediate member 42 also rotates. In this case, the intermediate member 42 hardly thermally expands, and the outer diameter surface 45 of the intermediate member 42 and the inner diameter surface 48 of the angular spring 46 are only in light contact. In this case, since the movement of both end portions 47a and 47b of the angular spring 46 is restricted by the movement restricting means 51, the angular spring 46 does not rotate, and the intermediate member 42 and the angular spring 46 slide. . That is, the intermediate member 42 rotates while generating some friction between the outer diameter surface 45 of the intermediate member 42 and the inner diameter surface 48 of the angular spring 46. Torque is generated on the rotating shaft 32 due to this sliding with friction. In this way, a certain amount of torque is generated in the rotating shaft 32 in a state below the first temperature.

Next, with reference to FIG. 7 etc., the case where it is more than 1st temperature, for example, the case where the temperature of the rotating shaft 32 rises to about 80 degreeC which is high temperature compared with normal temperature is demonstrated. When the rotating shaft 32 is rotated for a long time or the electromagnetic clutch 35 is frequently turned on and off, the temperature of the rotating shaft 32 rises. Then, the temperature of the intermediate member 42 conducts the heat from the rotating shaft 32 is also increased, the intermediate member 42 is thermally expanded toward the outer diameter side shown by the arrow D ₄ in FIG.

  In this case, the angular spring 46 also expands somewhat, but since the angular spring 46 is made of metal and the intermediate member 42 is made of resin, the amount of thermal expansion of the intermediate member 42 is larger. As a result, the outer diameter surface 45 of the intermediate member 42 presses the inner diameter surface 48 of the angular spring 46. Then, the angular spring 46 is rotated by the rotation of the rotation shaft 32. That is, the angular spring 46 is rotated together with the rotating shaft 32. In this case, one end portion 47a of the square spring 46 is engaged with the engagement hole 54, and movement is restricted. On the other hand, the end 47 b on the other side of the square spring 46 is engaged with a groove 61 provided in an arc shape, and the end 47 b moves to the end surface 62 a on one side of the groove 61. FIG. 5 corresponds to a diagram showing this state. Thereafter, the end portion 47b abuts on one end surface 62a of the groove portion 61, and the angular spring 46 is restricted from moving in the circumferential direction of the both end portions 47a and 47b. Thereafter, the angular spring 46 will be twisted. In this case, in order to rotate in the direction opposite to the winding direction of the square spring 46, a force acts in the direction in which the wound square spring 46 is unwound. As a result, the torque of the rotating shaft 32 decreases. Thus, torque can be reduced and torque can be adjusted.

  Next, a description will be given of a case where the torque is increased and adjusted at a high temperature. In this case, the rotation direction and the winding direction of the angular spring 46 are the same. In the normal temperature state, the same as above. In a high temperature state, the outer diameter surface 45 of the intermediate member 42 similarly presses the inner diameter surface 48 of the angular spring 46 by the thermal expansion of the intermediate member 42. Then, the angular spring 46 is rotated by the rotation of the rotation shaft 32. In this case, the other end 47b of the square spring 46 is engaged with a groove 61 provided in an arc shape, and the end 47b extends to the other end face 62b of the groove 61 as shown in FIG. Moving. FIG. 10 is a diagram illustrating a state in which the end portion 47 b is in contact with the other end surface 62 b of the groove portion 61, and corresponds to FIG. 5. In FIG. 10, the same reference numerals as those in FIG. Thereafter, the angular spring 46 is twisted by restricting the circumferential movement of both end portions 47a and 47b. In this case, in order to rotate in the same direction as the winding direction of the angular spring 46, a force acts in a direction in which the wound angular spring 46 is further wound. If it does so, the torque of the rotating shaft 32 will increase.

  In this way, the torque is adjusted. That is, according to the torque adjusting mechanism 41 of the rotating shaft 32, the movement of the both end portions 47a and 47b of the angular spring 46 is restricted. The intermediate member 42 and the square spring 46 slide, and a certain amount of torque can be applied to the rotating shaft 32. If the temperature is equal to or higher than the first temperature, the outer diameter surface 45 of the resin-made intermediate member 42 presses the inner diameter surface 48 of the angular spring 46 due to thermal expansion, and tries to rotate the angular spring 46. In this case, since the movement of both end portions 47a and 47b of the angular spring 46 is restricted, the torque can be increased or decreased according to the winding direction and the tightening force of the angular spring 46. Therefore, according to the torque adjusting mechanism 41 of the rotating shaft 32, a certain amount of torque can be applied to the rotating shaft 32 and the torque of the rotating shaft 32 can be adjusted appropriately even at high temperatures. In addition, the sheet conveying device 31 including such a torque adjusting mechanism that adjusts the torque of the rotating shaft 32 can convey the sheet more accurately. Furthermore, the digital multi-function peripheral 11 and the printing system including such a paper transport device 31 can print an appropriate image more reliably.

  In this case, since the material of the intermediate member is POM, it is possible to more efficiently and efficiently adjust the torque of the rotating shaft.

  Further, in this case, since the movement restricting means includes a fixing member provided with a groove portion that can engage one end portion of the angular spring, the torque of the rotating shaft can be adjusted more appropriately using the groove portion. Can do. In this case, since the groove is arcuate, the torque of the rotating shaft can be adjusted more smoothly.

  In this case, since the coil spring is a square spring, a large spring constant can be obtained in a relatively small space, and more efficient torque adjustment can be performed.

  In the above embodiment, when the torque is increased at a high temperature, the rotating shaft may be locked if the torque is equal to or higher than a predetermined torque. By so doing, even when the torque becomes excessive, it is possible to reduce the influence on the torque adjustment mechanism including the rotating shaft.

  In the above embodiment, the coil spring is a square spring manufactured by coiling a metal material having a square cross section. However, the present invention is not limited thereto, and the metal has a round cross section. A coil spring manufactured by coiling a material may be used, or a coil spring manufactured by coiling a metal material whose cross-section has another shape may be used.

  In the above embodiment, the movement restricting means is configured to restrict the movement of both ends of the coil spring. However, the movement restricting means is not limited to this, and the movement of at least one end of the coil spring is not limited thereto. You may comprise so that it may regulate. Moreover, it is good also considering the engaging hole provided in a side plate as a circular arc shape about the groove part of the fixing member provided as a movement control means. Furthermore, both may be arcuate grooves, and both may be in the form of engagement holes. Furthermore, the movement restricting means may be configured to restrict one end of the coil spring without using a fixing member or a side plate.

  In the above embodiment, the intermediate member is an annular shape. However, the present invention is not limited to this, and for example, a shape in which a part in the circumferential direction is cut, such as a C-shaped cross section. Alternatively, the coil spring positioned on the outer diameter side may be pressed by thermal expansion.

  In the above embodiment, POM is used as the material of the intermediate member. However, the material of the intermediate member is not limited to this, and PP (Polypropylene) or PC (Polycarbonate) is used as the material of the intermediate member. )) May be used. The material of the intermediate member may include at least one of POM, PP, and PC.

  In the above embodiment, SWP-B is used as the material of the coil spring. However, the present invention is not limited to this, and SUP-12 or SWC may be used as the material of the coil spring. . The material of the coil spring may include at least one of SWP-B, SUP-12, and SWC.

  In the above embodiment, the rotating shaft is configured to rotate the transport roller. However, the present invention is not limited thereto, and the rotating shaft may be configured to rotate the paper discharge roller, the pickup roller, and the like. The structure which rotates the member to rotate may be sufficient. Furthermore, it is applicable not only to the conveyance of paper but also to the case where, for example, the support shaft in the developing device is used as a rotation shaft or the torque is adjusted using the shaft for conveying the carriage provided in the image reading unit as the rotation shaft. Is done.

  In the above embodiment, the control of the paper transport device is performed by the control unit provided in the digital multifunction peripheral. However, the present invention is not limited to this, and the paper transport device has its own control unit. You may comprise so that control of a paper conveyance apparatus may be performed by the control part provided in the paper conveyance apparatus itself.

  It should be understood that the embodiments and examples disclosed herein are illustrative in all respects and are not restrictive in any respect. The scope of the present invention is defined by the scope of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the scope of the claims.

  The torque adjusting mechanism for the rotating shaft and the sheet conveying device according to the present invention are particularly effectively used when more appropriate adjustment of the torque of the rotating shaft is required.

  11 Digital MFP, 12 Control Unit, 13 Operation Unit, 14 Image Reading Unit, 15 Image Forming Unit, 16 Hard Disk, 17 Facsimile Communication Unit, 18 Network Interface Unit, 21 Display Screen, 22 ADF, 23 Developer, 24 Public Line , 25 network, 26a, 26b, 26c computer, 27 image processing system, 28 paper cassette, 31 paper transport device, 32 rotating shaft, 33 motor, 34 transport roller, 35 electromagnetic clutch, 36 paper discharge unit, 37 center, 38 , 45, 49 outer diameter surface, 41 torque adjusting mechanism, 42 intermediate member, 43a, 43b, 62a, 62b end surface, 44, 48 inner diameter surface, 46 angular spring, 47a, 47b, 59a, 59c end portion, 51 movement restricting means , 52 Side plate, 53, 58 Insertion hole, 5 Engaging holes, 56 fixing member, 57a, 57 b, 57c plate member 61 grooves.

Claims (7)

A torque adjusting mechanism for a rotating shaft that adjusts the torque of the rotating shaft,
A rotation axis;
An intermediate member made of resin, disposed on the outer diameter side of the rotating shaft, fixed to the rotating shaft, and rotated together with the rotating shaft;
A metal coil spring on which the intermediate member is disposed;
A movement restricting means for restricting movement of at least one end of the coil spring;
Below the first temperature, the intermediate member slides relative to the coil spring, and above the first temperature, the outer diameter surface of the intermediate member presses the inner diameter surface of the coil spring due to thermal expansion. Torque adjustment mechanism for the rotating shaft. The torque adjusting mechanism for a rotating shaft according to claim 1, wherein the rotating shaft is locked when a predetermined torque or more is reached. The material of the intermediate member includes at least one of POM (Polyoxymethylene), PP (Polypropylene), and PC (Polycarbonate). The torque adjusting mechanism of the described rotating shaft. The torque adjustment mechanism for a rotating shaft according to any one of claims 1 to 3, wherein the movement restricting means includes a fixing member provided with a groove portion capable of engaging one end portion of the coil spring. The torque adjusting mechanism for a rotating shaft according to claim 4, wherein the groove is provided in an arc shape. The torque adjustment mechanism for a rotating shaft according to claim 1, wherein the coil spring includes a square spring. A transport roller for transporting paper,
A rotating shaft for rotating the transport roller;
An intermediate member made of resin, disposed on the outer diameter side of the rotating shaft, fixed to the rotating shaft, and rotated together with the rotating shaft;
A metal coil spring on which the intermediate member is disposed;
A movement restricting means for restricting movement of at least one end of the coil spring;
Below the first temperature, the intermediate member slides relative to the coil spring, and above the first temperature, the outer diameter surface of the intermediate member presses the inner diameter surface of the coil spring due to thermal expansion. Paper transport device.

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