JP4764306B2 - Endless belt skew regulating device and image recording device - Google Patents

Description

  The present invention relates to an endless belt skew regulation device and an image recording apparatus including the endless belt skew regulation device.

  Endless belts supported by at least two tensioning rollers that are spaced apart from each other are well known in the art.

  It is also well known that such an endless belt tends to skew while being guided by at least two tension rollers.

  The skew of the endless belt is caused by a decrease in the parallelism between the rotation center lines of at least two stretching rollers, or the error in the lengths of both sides of the endless belt that occurs during the manufacture of the endless belt. It has been found that this is caused by a large difference in the extension of the lengths of both sides of the endless belt that occurs during use of the endless belt.

  When the endless belt is skewed, in an apparatus using the endless belt for conveying an object, the object conveyed by the endless belt may fall off from the endless belt or cannot be conveyed in a predetermined posture.

  An endless belt is used as an image recording medium conveying unit for conveying an image recording medium such as sheet paper, and an image recording medium such as sheet paper conveyed by the endless belt, for example, an inkjet head, An image recording apparatus that records a desired image using an image recording unit such as an ink transfer head or an electrophotographic recording apparatus having a photosensitive drum and a transfer device is also well known.

  In such an image recording apparatus, when the endless belt is skewed, the image recording unit may form a desired image at a desired position on an image recording medium such as a sheet of paper conveyed by the endless belt. In the case where wrinkles occur on the surface of the endless belt due to the skew of the endless belt, wrinkles also occur on the surface of the image recording medium such as a sheet of paper conveyed by the endless belt. All desired images may not be formed on the recording medium.

  In addition, an image recording medium such as a sheet of paper that has not been conveyed in a predetermined posture by the endless belt, or an image recording medium such as a sheet of paper that itself has been wrinkled due to wrinkles generated on the surface of the skewed endless belt, The endless belt is likely to cause clogging of the image recording medium, that is, a so-called paper jam, by colliding with an object disposed near the endless belt during conveyance by the endless belt.

As a configuration for preventing the skew of the endless belt, one outer peripheral surface of at least two tension rollers supporting the endless belt is formed into a gentle spindle shape (that is, a crown is attached). Is well known, and for example, from Japanese Patent Laid-Open No. 4-129944 (Patent Document 1), it is known that both ends of an endless belt are brought into sliding contact with an endless belt skew regulating member.
JP-A-4-129944

  By making one outer peripheral surface of at least two stretching rollers supporting the endless belt into a gentle spindle shape (that is, with a crown), the condition for determining the dimensions of such an outer peripheral surface is endless. The rigidity of the belt, the tension applied to the endless belt by the tension roller having such an outer peripheral surface, the tension applied to the endless belt by the tension roller having such an outer peripheral surface, and the other tension roller as the endless belt There are various conditions such as the balance between the tension applied to the belt and the friction condition between the tension roller having such an outer peripheral surface and the endless belt. Therefore, it is difficult to appropriately determine the size of such an outer peripheral surface for preventing the skew of the endless belt. Therefore, it is difficult to completely prevent the skew of the endless belt only by the shape of the outer peripheral surface. . Furthermore, the cost required for manufacturing a tension roller having such an outer peripheral shape is high.

  By sliding both ends of the endless belt into contact with the fixed member, the material of the endless belt itself is required to have high durability against sliding contact with the fixed member, and the dimensions of both ends of the endless belt are formed with high accuracy. It must be. Therefore, the material cost and manufacturing cost of the endless belt are high, and the durability of the endless belt is not high.

  Also, by attaching ribs extending along the extending direction of both end portions to both end portions of the inner peripheral surface of the endless belt, the rib material itself has high durability against contact with the end surface of the stretching roller. In addition to being required, high accuracy is required for the dimensions of the rib and the end surface of the tension roller with which the rib abuts. Moreover, high durability and high attachment position accuracy are required for attaching ribs to both end portions of the inner peripheral surface of the endless belt. Therefore, the material cost and manufacturing cost of the rib are high, and the cost of attaching the rib to both end portions of the inner peripheral surface of the endless belt is also high.

  By controlling the inclination of each of the at least two tension rollers according to the skew amount of the endless belt, various electrical and mechanical structures necessary for such control are complicated, and the manufacturing cost is reduced. Is expensive. Further, various foreign matters existing in the environment where the endless belt is placed, for example, dust adhered to the recording medium conveyed by the endless belt, small pieces of the recording medium separated from the recording medium, and endless separated from the endless belt. A small piece of the belt is likely to cause a malfunction in the skew sensor necessary for the above control.

  The present invention has been made under the various circumstances described above, and an object of the present invention is an endless belt skew regulation device and an image recording device which are simple in construction, inexpensive, excellent in durability and reliable in operation. Is to provide.

  In order to achieve the above-described object, an endless belt skew regulating device according to the present invention prevents an endless belt skew supported by at least two stretching rollers spaced apart from each other. A regulating device that abuts on the endless belt and rotates according to the movement of the endless belt, and supports a tension roller that applies tension to the endless belt, and the tension roller rotatably. A tension roller support unit that applies a force in the opposite direction to the tension roller that moves the belt in the width direction of the endless belt, and biases the tension roller in the opposite direction. It is said.

  In order to achieve the above-described object, an image recording apparatus according to the present invention records an image on an image recording medium conveyance unit that conveys an image recording medium, and an image recording medium that is conveyed by the image recording medium conveyance unit. An image recording apparatus comprising: an image recording unit that includes: at least two stretching rollers that are spaced apart from each other; and an image recording medium that is supported by at least two stretching rollers. An endless belt unit including an endless belt that supplies the image recording medium placed and placed to the image recording unit, and a tension roller that contacts the endless belt and rotates according to the movement of the endless belt, and applies tension to the endless belt And while supporting the tension roller freely, the endless belt skewed The endless bell has a tension roller support unit that applies a force in the opposite direction to the displacement force that moves the endless belt in the width direction of the endless belt, and urges the tension roller in the opposite direction. And a regulating device.

  According to the endless belt skew regulating device according to the present invention, which is configured as described above, the tension roller has a special shape such as a gentle spindle shape (that is, a crown) on the outer peripheral surface. It is not necessary to use an expensive material with excellent durability as the material of the endless belt, and it is not necessary to make the dimensional accuracy of the endless belt particularly precise. There is no need to attach a special object such as a rib, and it does not require various expensive electrical and mechanical structures, and various foreign substances existing in the environment where the endless belt is placed, such as an endless belt Is separated from dust adhering to the recording medium transported by the recording medium, small pieces of the recording medium separated from the recording medium, and endless belts. Pieces such as the endless belt, very little possibility of causing malfunction by. Therefore, the endless belt skew regulation device according to the present invention, which is configured as described above, has a simple configuration, is inexpensive, has excellent durability, and operates reliably.

  The two image recording apparatuses according to the present invention, which are configured as described above, include the endless belt skew regulating device according to the present invention. Naturally, the above-described various effects provided by the belt skew control device can be enjoyed.

[First embodiment]
First, referring to FIG. 1, an electrophotographic tandem color image recording apparatus 12 which is a kind of image recording apparatus provided with an endless belt skew feeding regulating device 10 according to the first embodiment of the present invention. explain.

  The electrophotographic tandem color image recording apparatus 12 includes two stretching rollers 14a that are rotatably arranged at predetermined positions in the housing 13 that are spaced apart from each other in the substantially horizontal direction along the bottom wall of the housing 13. , 14b and an endless belt unit 18 supported by two stretching rollers 14a, 14b. The endless belt unit 18 further includes a rotational drive source 20 that rotationally drives one tension roller 14a in a predetermined direction at a predetermined speed. The rotational drive source 20 includes a stepping motor 20a and a rotational force transmission mechanism 20b such as a timing belt that transmits the rotational force of the stepping motor 20a to one stretching roller 14a.

  In this embodiment, when one tension roller 14a is rotationally driven in a predetermined direction at a predetermined speed by the rotation drive source 20, the endless belt 16 has the upper side between the two tension rollers 14a and 14b as shown in FIG. In FIG. 1, the lower side between the two stretching rollers 14a and 14b is moved from one other stretching roller 14b to the other stretching roller 14b as indicated by the arrow T. It is moved from 14b to another tension roller 14b in the direction opposite to the arrow T.

  A static application roller 22 is pressed on the outer peripheral surface of another tension roller 14b via an endless belt 16, and the endless belt 16 is disposed upstream of the static application roller 22 in the transport direction of the endless belt 16. The static eliminating device 24 is opposed to the other.

  First in the moving direction T of the upper side along the upper side of the endless belt 16 supported by the two tension rollers 14a and 14b in the housing 13 toward another tension roller 14b from the other tension roller 14b. The fourth to fourth image recording units 26Y, 26M, 26C, and 26B are arranged in this order.

  Each of the first to fourth image recording units 26 </ b> Y, 26 </ b> M, 26 </ b> C, and 26 </ b> B includes a photosensitive drum 28 disposed adjacent to the upper side of the endless belt 16. The photosensitive drum 28 can rotate at the same peripheral speed and rotational direction as the moving speed and moving direction of the upper side of the endless belt 16. Around the photosensitive drum 28, a cleaning blade 30, a charging device 32, and a toner developing device 34 are arranged along the rotation direction of the photosensitive drum 28. Further, a transfer device 36 is disposed on the outer peripheral surface of the photosensitive drum 28 via the upper side of the endless belt 16.

  An exposure device 38 for the outer peripheral surface of each photosensitive drum 28 is disposed in the housing 13 above the first to fourth image recording units 26Y, 26M, 26C, and 26B. The exposure device 38 is a laser exposure device that uses a laser beam and an optical system. Further, the housing 13 further includes an exposure apparatus control unit 40 for controlling the operation of the exposure apparatus 38 and an image signal transmission for transmitting an image signal serving as a basis for controlling the operation of the exposure apparatus control unit 40 to the exposure apparatus control unit 40. A unit 42 is arranged.

  Each of the first to fourth image recording units 26Y, 26M, 26C, and 26B has the cleaning blade 30 of the photosensitive drum 28 while the photosensitive drum 28 rotates at a predetermined speed in a predetermined direction. All the objects adhering to the outer peripheral surface are removed, the charging device 32 uniformly charges the outer peripheral surface of the photosensitive drum 28 with a predetermined charge, and the exposure device 38 uniformly determines the predetermined photosensitive drum 28. A laser beam is irradiated on the outer peripheral surface charged with the electric charge to form an electrostatic latent image corresponding to an image to be formed on the outer peripheral surface of each photosensitive drum 28 on the outer peripheral surface, and toner The developing device 34 develops the electrostatic latent image on the outer peripheral surface of the photosensitive drum 28 with the toner held by the toner developing device 34 to form a toner image. That is, in this embodiment, the photosensitive drum 28 functions as an image holding body on which a toner image is formed and holds the formed toner image.

  In this embodiment, the toner developing device 34 of the first image recording unit 26Y holds yellow toner, the toner developing device 34 of the second image recording unit 26M holds magenta toner, and the third toner recording device 26Y. The toner developing device 34 of the image recording unit 26C holds cyan toner, and the toner developing device 34 of the fourth image recording unit 26B holds black toner.

  A fixing device 44 is disposed in the housing 13 at a position spaced apart in the moving direction T on the upper side of the endless belt 16 with respect to one stretching roller 14 a of the endless belt unit 18. The fixing device 44 includes a pair of heating rollers 44a and 44b.

  In the electrophotographic tandem type color image recording apparatus 12 configured as described above, the endless belt 16 of the endless belt unit 18 is predetermined by the rotational driving force supplied from the rotational driving source 20 to one stretching roller 14a. Between the surface portion of the endless belt 16 on the outer peripheral surface of the other tension roller 14b of the endless belt unit 18 and the static electricity applying roller 22 from the outside of the housing 13 while moving at a predetermined speed in the direction of When an image recording medium P such as a sheet of paper having a predetermined shape and size is supplied between them, the image recording medium P is transferred to the endless belt 16 on the outer peripheral surface of the other stretching roller 14b by the static electricity applying roller 22. The endless belt 16 is pressed against the surface by static electricity generated by the static electricity applying roller 22. It is attached to the surface.

  Thereafter, the image recording medium P is moved at a predetermined speed in a predetermined movement direction T together with the upper side of the endless belt 16 in a state of being attached to the surface of the upper side of the endless belt 16 as described above. That is, in the tandem type color image recording apparatus 12, the endless belt unit 18 functions as an image recording medium conveyance unit that conveys the image recording medium P together with the endless belt skew regulation apparatus 10.

  Each of the first to fourth image recording units 26Y, 26M, 26C, and 26B is attached to the surface of the upper side of the endless belt 16 at a position where the outer peripheral surface of each photosensitive drum 28 is adjacent to the upper side of the endless belt 16. When the position where the transfer of the toner image on the outer peripheral surface of the corresponding photosensitive drum 28 arrives on the image recording medium P arrives, the photosensitive drum 28 is transferred by the transfer device 36 on the opposite side across the endless belt 16. Transfer of the toner image on the outer peripheral surface of the image recording medium P is started. That is, the transfer unit 36 is fed from the photosensitive drum 28 as the image holding body of each of the first to fourth image recording units 26Y, 26M, 26C, and 26B by the endless belt unit 18 as the image recording medium conveyance unit. An image for transferring a toner image held by the photosensitive drum 28 as the image holding body of each of the first to fourth image recording units 26Y, 26M, 26C, and 26B to the image recording medium P being conveyed. It functions as a transfer unit.

  Accordingly, while the image recording medium P is attached to the surface of the upper side of the endless belt 16 as described above and moved along with the upper side of the endless belt 16 in the predetermined moving direction T at the predetermined speed, the first to fourth. Each time the image recording units 26Y, 26M, 26C, and 26B pass under the outer peripheral surfaces of the respective photosensitive drums 28, the toner images on the respective photosensitive drums 28 are transferred to positions to be transferred. .

  The image recording medium after the toner images to be transferred from the outer peripheral surfaces of the respective photosensitive drums 28 of the first to fourth image recording units 26Y, 26M, 26C, and 26B are transferred to the positions to be transferred. P is peeled off from the upper side of the endless belt 16 against adhesion due to static electricity when the upper side of the endless belt 16 reaches one stretching roller 14a and the direction of movement is changed along the outer peripheral surface of one stretching roller 14a. And sent out to the fixing device 44. Then, the above-described various images transferred from the outer peripheral surfaces of the photosensitive drums 28 of the first to fourth image recording units 26Y, 26M, 26C, and 26B to the positions to be transferred on the image recording medium P are described. The color toner image is transferred to the pair of heating rollers 44a and 44b while the image recording medium P is sandwiched between the pair of heating rollers 44a and 44b of the fixing device 44 and passes between the pair of heating rollers 44a and 44b. Is fixed at a position to be transferred on the image recording medium P by the pressure and heat applied by.

  The electrophotographic tandem color image recording apparatus 12 configured as described above and operating as described above is well known.

  In the electrophotographic tandem color image recording apparatus 12 described above, the opening of the housing 13 located on the side opposite to the moving direction T of the upper side of the endless belt 16 with respect to the other stretching roller 14b of the endless belt unit 18. The image recording medium P is supplied between the surface portion of the endless belt 16 on the outer peripheral surface of the other tension roller 14 b of the endless belt unit 18 and the static electricity applying roller 22. However, the electrophotographic tandem type color image recording apparatus 12 described above is provided between the surface portion of the endless belt 16 on the outer peripheral surface of the other stretching roller 14b of the endless belt unit 18 and the static electricity applying roller 22. An opening formed in the bottom wall of the housing 13 located below the other stretching roller 14b of the endless belt unit 18 from an image recording medium supply device such as an image recording medium supply cassette disposed below the housing 13. The image recording medium P can also be supplied via this.

  In general, the allowable value of color misregistration in a color image is several tens of μm, and each of the first to fourth image recording units 26Y, 26M, 26C, and 26B is located on the image recording medium P on the endless belt 16. The position at which the toner image is transferred (that is, the position where the photosensitive drums 28 of the first to fourth image recording units 26Y, 26M, 26C, and 26B are adjacent to the image recording medium P on the endless belt 16). The distance between them is about 300 mm to about 500 mm, and in rare cases, it may be set to about 1000 mm.

  Accordingly, in the endless belt unit 18, when the moving endless belt 16 begins to skew (a phenomenon in which the endless belt 16 moves in a direction perpendicular to the moving direction), the image recording medium on the endless belt 16 is started. With respect to P, color misregistration begins to occur between the toner images formed by the first to fourth image recording units 26Y, 26M, 26C, and 26B. If the skew amount of the endless belt 16 increases, the color misregistration amount exceeds the allowable value.

  The endless belt skew regulating device 10 according to the first embodiment of the present invention functions to regulate such skew of the endless belt 16, and in this embodiment, the bottom of the housing 13 in the housing 13. It is provided on the wall and is applied to the lower side of the endless belt 16 of the endless belt unit 18.

  Next, the configuration of the endless belt skew regulating device 10 according to the first embodiment of the present invention will be described with reference to FIGS.

  The endless belt skew regulating device 10 includes a tension roller 50 that contacts the endless belt 16 and rotates according to the movement of the endless belt 16 and applies tension to the endless belt 16. The rotation center axis 50CL of the tension roller 50 extends in parallel to the surface of the endless belt 16 in the width direction orthogonal to the moving direction of the endless belt 16. The length of the outer peripheral surface of the tension roller 50 in the direction along the rotation center axis 50CL of the tension roller 50 is set to be larger than the length of the endless belt 16 in the width direction.

  The endless belt skew regulating device 10 also includes a tension roller support unit 52 that rotatably supports the tension roller 50. The tension roller support unit 52 supports the tension roller 50 so as to be movable in a direction Z intersecting the surface of the endless belt 16, and urges the tension roller 50 toward the endless belt 16 to press the endless belt 16 to endlessly press the endless belt 16. A tension generating unit 54 that generates tension on the belt 16 is provided.

  The tension roller support unit 52 includes a first support 56 that rotatably supports both end portions of the rotation center shaft 50a of the tension roller 50, and the rotation support center axis 50CL of the tension roller 50 and the endless belt. 16 is interposed between a first support 56 and a second support 58, which is supported so as to be swingable around a rotation center axis 58CL oriented in a direction intersecting the surface of the sixteen. Biasing unit 60.

  The tension roller support unit 52 further swings the second support 58 around the rotation center axis 62CL extending along the surface of the endless belt 16 in parallel with the surface of the endless belt 16 and orthogonal to the moving direction of the endless belt 16. It includes a third support 62 that is movably supported. The third support 62 is fixed to the base 64, and the base 64 is fixed to a predetermined position on the inner surface of the bottom wall of the housing 13 of the tandem color image recording apparatus 12 shown in FIG. Has been.

  Specifically, the first support 56 includes a substantially C-shaped first frame that is square with the left and right sides reversed in plan view, and a pair of arms at both ends of the first frame are Both ends of the rotation center shaft 50a of the tension roller 50 are rotatably supported through bearings 50b. A bearing support portion 50c is fixed at the center position in the extending direction at the center portion of the first frame that faces the same direction as the rotation center axis 50CL of the tension roller 50 and extends parallel to the rotation center axis 50CL. . The bearing support portion 50c supports a bearing 50d disposed concentrically with the rotation center axis 58CL.

  The second support 58 includes a first rotation center shaft 58a that is disposed concentrically with the rotation center axis 58CL. The upper end portion of the first rotation center shaft 58a is rotatably supported by the bearing 50d of the bearing support portion 50c at the center position of the center portion of the first frame of the first support 56, and the bearing 50d is The first frame of the first support 56 is supported so as to be swingable about the rotation center axis 58CL with respect to the rotation center axis 58CL of the first rotation center axis 58a of the second support 58. The second support 58 includes a rotation center shaft support member 58b to which the lower end of the first rotation center shaft 58a is fixed. The second support 58 further includes a second rotation center shaft 58c extending concentrically with the rotation center axis 62CL on both sides in the extending direction of the rotation center axis 62CL from the rotation center shaft support member 58b.

  The third support body 62 includes a pair of bearing support members 62a spaced from each other by a predetermined distance in the direction along the rotation center axis 62CL on the surface of the base 64. The pair of bearing support members 62 a are fixed to the surface of the base 64. Both ends of the second rotation center shaft 58c of the second support 58 are rotatable around the rotation center axis 62CL by bearings supported by a pair of bearing support members 62a of the third support 62. It is supported.

  In the tension roller support unit 52, the biasing unit 60 interposed between the first support 56 and the second support 58 is fixed to the upper end portion of the rotation center shaft 58 a of the second support 58. A torsion coil spring 60a having one end and the other end fixed to the bearing support 50c at the center position of the center of the first frame of the first support 56. The torsion coil spring 60a is a center of rotation of the rotation center shaft 50a of the tension roller 50 supported by the first support body 56 in a neutral state where no torsional force is applied to the torsion coil spring 60a. The axis 50CL is directed parallel to the surface of the lower side of the endless belt 16 and in a direction orthogonal to the moving direction of the endless belt 16.

  When the first frame of the first support 56 is rotated around the rotation center axis 58CL of the second support 58 from the neutral state to one or the other, the urging unit 60 rotates the same. If it is an angle, a torsional force in the opposite direction of the same magnitude is generated.

  The tension generating unit 54 of the endless belt skew regulating device 10 includes a pair of elastic members 54 a interposed between a pair of arms at both ends of the first frame of the first support 56 and the base plate 64. including. The pair of elastic members 54a urges the tension roller 50 supported by the first support 56 toward the surface of the lower side of the endless belt 16, and the outer peripheral surface of the tension roller 50 is brought to the surface of the lower side of the endless belt 16. The endless belt 16 is tensioned by pressing.

  In this embodiment, each of the pair of elastic members 54a is composed of the same coil spring, and the first frame of the first support 56 is the rotation center axis 58CL of the second support 58. When the rotation is rotated from the neutral state described above to one or the other around the same, a pulling force in the opposite direction of the same magnitude is generated at the same rotation angle.

  Next, the operation of the endless belt skew regulating device 10 according to the first embodiment of the present invention will be described with reference to FIG.

  When skew occurs in the moving endless belt 16, a shift force is generated in the endless belt 16 in the width direction perpendicular to the moving direction as indicated by an arrow S in FIG. This displacement force causes the first support 56 of the endless belt skew regulating device 10 supporting the tension roller 50 that is in contact with the lower side of the endless belt 16 to rotate the second support 58 in the first rotation. The center shaft 58a is urged in the direction in which the shift force is directed around the rotation center axis 58CL, and is rotated in the direction in which the shift force is directed.

  This rotation of the first support 56 causes the displacement force to be applied to the torsion coil spring 60a of the urging unit 60 interposed between the first support 56 and the second support 58. A torsional reaction force is generated in a direction opposite to the direction toward the direction. This torsional reaction force is applied to the tension roller 50 as a moment force related to the distance L from the rotation center axis 58CL of the first rotation center shaft 58a of the second support 58 to the rotation center axis 50CL of the tension roller 50. Works.

  The rotation of the first support 56 and the skew of the endless belt 16 are the displacement force generated by the skew of the endless belt 16 and the torsion coil of the urging unit 60. The torsional reaction force generated in the spring 60a stops at a position where the component force in the width direction of the endless belt 16 is balanced with the moment force generated by the tension roller 50 in contact with the lower side of the endless belt 16. That is, the distance that the endless belt 16 moves in the width direction due to the skew is limited to a predetermined range and is not increased beyond the predetermined range.

[Modification of First Embodiment]
Next, a modification of the endless belt skew regulating device 10 according to the first embodiment of the present invention described above with reference to FIGS. 2 to 5 will be described with reference to FIG.

  Most of the constituent members of the endless belt skew regulating device 10 'of this modification are the same as the most constituent members of the endless belt skew regulating device 10 according to the first embodiment of the present invention described above. is there. In the endless belt skew regulating device 10 ′ of this modification, the same constituent members as those of the endless belt skew regulating device 10 according to the first embodiment are used as the endless belt according to the first embodiment. The same reference numerals as those given to the constituent members of the belt skew regulating device 10 are attached, and detailed description thereof is omitted.

  The configuration of the endless belt skew regulating device 10 'of this modification is different from the configuration of the endless belt skew regulating device 10 according to the first embodiment in that the first support 56 and the second support A configuration of an urging unit 60 ′ interposed between the support body 58 and a configuration of a rotation center shaft support member 58 ′ b that supports the urging unit 60 ′ in the second support body 58.

  In this modification, the rotation center shaft support member 58′b extends long along the center portion of the first frame of the first support 56, and the urging unit 60 ′ includes the rotation center shaft support member 58 ′. The same pair of elastic bodies at the same distance from the first rotation center axis 58CL of the first rotation center shaft 58a supported by the rotation center shaft support member 58'b at both ends in the longitudinal direction of b. 60'a is supported. The pair of elastic bodies 60 ′ a is also supported by a pair of positions corresponding to the pair of elastic bodies 60 ′ a at the center of the first frame of the first support 56. The support 56 is interposed between the second support 58 and the second support 58. Each of the pair of elastic bodies 60'a can be constituted by a coil spring, for example.

  In this modification, the pair of elastic bodies 60'a of the urging unit 60 'are connected to the torsion coil spring 60a of the urging unit 60 of the endless belt skew regulating device 10 according to the first embodiment. Works in the same way.

  That is, the moving endless belt 16 is skewed, and a shift force is generated in the endless belt 16 in the width direction orthogonal to the moving direction as indicated by an arrow S in FIG. The first support 56 of the endless belt skew regulating device 10 that supports the tension roller 50 that is in contact with the lower side of the endless belt 16 by the shift force is the first rotation center of the second support 58. When the shift force is turned around the rotation center axis 58CL of the shaft 58a, the rotation of the first support 56 is caused by the first support 56 and the second support 58. A compressive force is applied to one of the pair of elastic bodies 60'a of the biasing unit 60 'interposed therebetween, and a tensile force is applied to the other. As a result, a reaction force against the compression force is generated in one of the pair of elastic bodies 60'a, and a reaction force against the tensile force is generated in the other, and these reaction forces are generated by the first rotation of the second support body 58. It acts on the tension roller 50 as a moment force related to the distance from the rotation center axis 58CL of the center shaft 58a to the rotation center axis 50CL of the tension roller 50.

  Then, the rotation of the first support 56 and the skew of the endless belt 16 are a pair of the biasing unit 60 'and the above-mentioned shift force generated by the skew of the endless belt 16 on the endless belt 16. The reaction force generated in the elastic body 60'a stops at a position where the component force in the width direction of the endless belt 16 in the moment force generated by the tension roller 50 in contact with the lower side of the endless belt 16 is balanced. That is, the distance that the endless belt 16 moves in the width direction due to the skew is limited to a predetermined range and is not increased beyond the predetermined range.

[Second Embodiment]
Next, the configuration of the endless belt skew regulating device 70 according to the second embodiment of the present invention will be described in detail with reference to FIG.

  The endless belt skew regulating device 70 also includes a tension roller 72 that contacts the endless belt 16 (see FIG. 1), rotates according to the movement of the endless belt 16, and applies tension to the endless belt 16. The rotation center axis 72CL of the tension roller 72 extends parallel to the surface of the endless belt 16 in the width direction orthogonal to the moving direction of the endless belt 16. The length of the outer peripheral surface of the tension roller 72 in the direction along the rotation center axis 72CL of the tension roller 72 is set larger than the length of the endless belt 16 in the width direction.

  The endless belt skew regulating device 70 also includes a tension roller support unit 74 that rotatably supports the tension roller 72. The tension roller support unit 74 supports the tension roller 72 so as to be movable in the direction Z intersecting the surface of the endless belt 16, and urges the tension roller 72 toward the endless belt 16 to press the endless belt 16 to endlessly. A tension generating unit 76 that generates tension on the belt 16 is provided.

  The tension roller support unit 74 includes a first support body 80 including a pair of support members 78 that rotatably support both ends of a rotation center shaft 72a of the tension roller 72 via bearings 78a, and is shown in FIG. And a base plate 82 fixed to a predetermined position on the inner surface of the bottom wall of the housing 13 of the tandem type color image recording apparatus 12.

  The tension generating unit 76 is interposed between the first support 80 and the base plate 82. In this embodiment, in the first support 80, in the vicinity of both ends of the central portion 80a between the pair of support members 78. And a pair of coil springs 76a fixed to two positions on the base plate 82 corresponding thereto.

  Each of the pair of support members 78 includes an elastic member that exhibits an elastic force in a direction along the rotation center axis 72CL of the tension roller 72 and constitutes the urging unit 84. In this embodiment, the elastic member is, for example, It is comprised by the leaf | plate spring.

  Next, the operation of the endless belt skew regulating device 70 according to the second embodiment of the present invention will be described in detail with reference to FIG.

  When skew occurs in the moving endless belt 16, a shift force is generated in the endless belt 16 in the width direction perpendicular to the moving direction as indicated by an arrow S in FIG. This displacement force is applied to the first support 80 of the endless belt skew regulating device 70 that supports the tension roller 72 in contact with the lower side of the endless belt 16 in the direction in which the displacement force is directed (that is, tension). The pair of support members 78 of the first support 80 are deflected against the respective elastic force K / 2 in the direction in which the displacement force is urged in the direction along the rotation center axis 72CL of the roller 72. I will.

  The bending of each of the pair of support members 78 of the first support member 80 and the skew of the endless belt 16 are the deviation force generated by the skew of the endless belt 16 and the shift force of the endless belt 16. The elastic force K generated in the pair of support members 78 of one support 80 is stopped at a position where the force generated by the tension roller 72 in contact with the lower side of the endless belt 16 is balanced. That is, the distance that the endless belt 16 moves in the width direction due to the skew is limited to a predetermined range and is not increased beyond the predetermined range.

[Modification of image recording apparatus]
The endless belt skew regulating device 10 according to the first embodiment of the present invention described above with reference to FIGS. 2 to 5 and the endless belt skew regulating device according to the modification described with reference to FIG. The endless belt unit 18 using the endless belt 16 to which each of the endless belt skew regulating devices 70 according to the second embodiment of the present invention described above with reference to FIG. 1 functions as an image recording medium transport unit that transports the image recording medium P in a predetermined direction at a predetermined speed in the electrophotographic tandem color image recording apparatus 12 that is a kind of the image recording apparatus shown in FIG. .

  However, the image recording apparatus in which the endless belt unit 18 is used includes an image recording unit including four or less or four or more electrophotographic image recording units that form four or less types or four or more types of toner images. The image recording apparatus may be an apparatus, or may be an image recording apparatus including one or a plurality of image recording units, for example, an ink jet head or an ink transfer method.

  FIG. 8 shows an outline of an electrophotographic tandem type color image recording apparatus 90 which is still another type of image recording apparatus provided with the endless belt skew feeding regulating device 10 according to the first embodiment of the present invention. A typical longitudinal section is shown.

  Note that most of the constituent members of the electrophotographic tandem color image recording apparatus 90 are the same as most of the constituent members of the electrophotographic tandem color image recording apparatus 12 shown in FIG. . Therefore, in the electrophotographic tandem color image recording apparatus 90, the same constituent members as those of the electrophotographic tandem color image recording apparatus 12 shown in FIG. 1 are shown in FIG. The same reference numerals as those given to the constituent members of the electrophotographic tandem type color image recording apparatus 12 are given, and detailed explanations of these constituent members are omitted.

  The electrophotographic tandem color image recording apparatus 90 is different from the electrophotographic tandem color image recording apparatus 12 shown in FIG. 1 in that the endless belt 16 'of the endless belt unit 18 records. Images that are not used for transporting the medium P but are recorded by the first to fourth image recording units 26Y, 26M, 26C, and 26B, and that transport the recorded toner images. It functions as a conveyor belt. Therefore, the material of the endless belt 16 'of the electrophotographic tandem color image recording apparatus 90 is the same as the material of the endless belt 16 of the electrophotographic tandem color image recording apparatus 12 shown in FIG. Is different.

  The electrophotographic tandem color image recording apparatus 90 is configured to endlessly transfer the toner images recorded and conveyed on the endless belt 16 'by the first to fourth image recording units 26Y, 26M, 26C, and 26B. An image transfer unit 92 for transferring to the image recording medium P supplied toward the belt 16 'is provided.

  In this electrophotographic tandem color image recording apparatus 90, the image transfer unit 92 holds the lower side of the endless belt 16 'between the two stretching rollers 14a and 14b on the upstream side of the endless belt skew regulating apparatus 10. A pair of transfer rollers 92a and 92b is included. The pair of transfer rollers 92a and 92b are heated, and the endless belt 16 and the outer surface portion of the lower side of the endless belt 16 'positioned on the outer peripheral surface of the transfer roller 92a positioned inside the lower side of the endless belt 16'. When the image recording medium P is supplied between the transfer roller 92b positioned outside the lower side of the ′, the lower side of the endless belt 16 ′ and the image recording medium P are sandwiched and brought into close contact with each other while being heated. The toner image recorded on the above portion of the outer surface of the lower side of the belt 16 ′ is transferred and fixed on the image recording medium P.

  That is, in the tandem color image recording apparatus 90, the endless belt unit 18 together with the endless belt skew feeding regulating apparatus 10, the first to fourth image recording units 26Y, 26M, 26C, and 26B respectively generate toner images. It functions as an image transport unit that transports a recorded and recorded toner image.

  The electrophotographic tandem color image recording apparatus 90 further includes a cleaner 94 that removes various foreign substances adhering to the outer surface of the endless belt 16 'between the image transfer unit 92 and the first image recording unit 26Y. It has.

  The endless belt according to the first embodiment of the present invention described above with reference to FIGS. 2 to 5 used in the electrophotographic tandem type color image recording apparatus 90 shown in FIG. Instead of the skew regulating device 10, the endless belt skew regulating device 10 'of the modified example described above with reference to FIG. 6 and the endless according to the second embodiment of the present invention described above with reference to FIG. Each of the belt skew regulating devices 70 can also be used.

  Furthermore, the endless belt unit 18 that functions as an image transport unit that transports the recorded toner image together with the endless belt skew regulating device 10 forms four or less types or four or more types of toner images. It can be used in an image recording apparatus including four or less or four or more electrophotographic image recording units, and includes one or a plurality of image recording units using, for example, an inkjet head or an ink transfer method. It can also be used in existing image recording devices.

FIG. 1 is a schematic longitudinal sectional view of an electrophotographic tandem color image recording apparatus which is a kind of an image recording apparatus provided with an endless belt skew feeding regulating device according to the first embodiment of the present invention. is there. FIG. 2 is a schematic perspective view of the endless belt unit in the tandem type color image recording apparatus of FIG. 1 and the endless belt skew regulating device according to the first embodiment of the present invention applied to the endless belt unit. FIG. FIG. 3 is a schematic perspective view of the endless belt skew regulating device according to the first embodiment of the present invention. FIG. 4A is a schematic plan view of the endless belt skew regulating device according to the first embodiment of the present invention; and FIG. 2) is a schematic side view of the endless belt skew regulating device. FIG. 5A schematically shows a state in which the endless belt skew regulating device according to the first embodiment of the present invention is applied to the endless belt unit of the tandem type color image recording apparatus of FIG. 5B is a side view of the endless belt of the tandem type color image recording apparatus shown in FIG. 1 in the endless belt according to the first embodiment of the present invention. It is a schematic bottom view which shows a mode that a belt skew feeding control apparatus controls. FIG. 6 is a perspective view schematically showing a modification of the endless belt skew regulating device according to the first embodiment of the present invention. FIG. 7A is a schematic perspective view of an endless belt skew regulating device according to the second embodiment of the present invention; and FIG. 7B is a diagram (A) of FIG. FIG. 6 is a front view schematically showing an operation principle in which the endless belt skew regulation device according to the second embodiment of the present invention shown in FIG. FIG. 8 is a schematic longitudinal cross-sectional view of an electrophotographic tandem color image recording apparatus which is still another type of image recording apparatus provided with the endless belt skew regulating device according to the first embodiment of the present invention. FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Endless belt skew control apparatus (image recording medium conveyance unit), 12 ... Tandem type color image recording apparatus, 13 ... Housing, 14a, 14b ... Stretching roller, 16, 16 '... Endless belt, 18 ... Endless belt unit (Image recording medium transport unit), 20 ... rotational drive source, 20a ... stepping motor, 20b ... rotational force transmission mechanism, 22 ... static electricity applying roller, 24 ... static electricity removing device, 26Y ... first image recording unit, 26M ... first 2 image recording units, 26C ... third image recording unit, 26B ... fourth image recording unit, 28 ... photosensitive drum (image holding member), 30 ... cleaning blade, 32 ... charging device, 34 ... toner developing device , 36 ... transfer device (image transfer unit), 38 ... exposure device, 40 ... exposure device control unit, 42 ... Image signal transmission unit 44 ... Fixer 44a, 44b ... Heating roller, P ... Image recording medium 50 ... Tension roller 50a ... Rotation center shaft 50b ... Bearing 50c ... Bearing support 50d ... Bearing 50CL ... Rotation center axis, 52 ... tension roller support unit, 54 ... tension generation unit, 54a ... elastic member, 56 ... first support, 58 ... second support, 58a ... first rotation center axis, 58b ... rotation Center axis support member, 58c ... second rotation center axis, 58CL ... rotation center axis, 60, 60 '... biasing unit, 60a ... torsion coil spring, 62 ... third support, 62a ... bearing support member , 62CL ... rotation center axis, 64 ... base, 70 ... endless belt skew regulating device, 72 ... tension roller, 72a ... rotation center axis, 72CL ... rotation center axis, 74 ... ten Roller support unit, 76 ... tension generating unit, 76a ... coil spring, 78 ... support member, 78a ... bearing, 80 ... first support, 80a ... central part, 82 ... base plate, 84 ... biasing unit, 90 ... tandem Type color image recording apparatus, 92... Image transfer unit, 92 a, 92 b... Transfer roller, 94.

Claims (8)

An endless belt skew regulating device for preventing skew of an endless belt supported by at least two stretching rollers spaced apart from each other,
A tension roller that is in contact with the endless belt and rotates according to the movement of the endless belt, and applies tension to the endless belt;
The tension roller is supported rotatably, and a force in the opposite direction is applied to the tension roller to shift the endless belt in the width direction of the endless belt when the endless belt is skewed. A tension roller support unit biasing in the opposite direction;
An endless belt skew regulating device comprising:   The tension roller support unit supports the tension roller so as to be movable in a direction crossing the surface of the endless belt, and urges the tension roller toward the endless belt to press the endless belt to generate tension on the endless belt. The endless belt skew regulating device according to claim 1, further comprising a generation unit. The tension roller support unit
A first support that rotatably supports the tension roller;
A second support that supports the first support in a swingable manner about a rotation center axis that is oriented in a direction intersecting the rotation center axis of the tension roller and the surface of the endless belt;
A tension roller that is interposed between the first support and the second support, and that has a force in the opposite direction to the shifting force that moves the endless belt in the width direction of the endless belt when the endless belt is skewed. An urging unit for urging the tension roller in the opposite direction around the rotation center axis oriented in a direction intersecting the surface of the endless belt.
The endless belt skew regulation device according to claim 1.   The biasing unit is a torsion spring having one end fixed to the rotation center axis of the second support and the other end fixed to the first support. The endless belt skew regulating device as described.   The tension roller support unit supports the tension roller so as to be movable in a direction crossing the surface of the endless belt, and urges the tension roller toward the endless belt to press the endless belt to generate tension on the endless belt. The endless belt skew regulation device according to claim 3, further comprising a generation unit.   The tension roller support unit includes a third support that swingably supports the second support around a rotation center axis extending in a direction along the surface of the endless belt. The endless belt skew feeding device according to claim 5. The tension roller support unit includes a first support that rotatably supports the tension roller, and a direction opposite to a force that is generated in the endless belt when the endless belt is skewed and moves the endless belt in the width direction of the endless belt. An urging unit that applies a force toward the first support to the first support,
The endless belt skew regulation device according to claim 1. An image recording apparatus comprising an image recording medium conveying unit for conveying an image recording medium, and an image recording unit for recording an image on an image recording medium conveyed by the image recording medium conveying unit,
The image recording medium transport unit
Endless including at least two stretching rollers that are spaced apart from each other, and an endless belt that is supported by at least two stretching rollers and on which the image recording medium is mounted and that supplies the image recording medium to the image recording unit A belt unit;
The endless belt is in contact with the endless belt and rotates according to the movement of the endless belt. The tension roller that applies tension to the endless belt and the tension roller is rotatably supported. An endless bell skew regulating device having a tension roller support unit that applies a force in the opposite direction to the tension roller to move in the opposite direction, and urges the tension roller in the opposite direction. ,
An image recording apparatus.

Images