JP2010230958A - Mechanism for correcting belt-meandering and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mechanism for correcting belt-meandering capable of suppressing wearing of a belt, and to provide an image forming apparatus. <P>SOLUTION: The mechanism 100 for correcting belt-meandering includes: a base 50 having a force conversion member 52 which receives a first pressurizing force a resulting from the meandering of the intermediate transfer belt 33 and converts the first pressurizing force a to a roll oscillating force b, and also, receives a second pressurizing force d resulting from a roll oscillation recovery force c and converts the second pressurizing force d to a correction force e to correct the meandering of the intermediate transfer belt 33; and a belt-meandering correction roll 31 which oscillates when receiving the roll oscillating force b from the force conversion member 52, and also, which oscillates and recovers when receiving the roll oscillation recovery force c, wherein a belt meandering correcting member 58 for correcting the meandering of the intermediate transfer belt 33 is arranged at the end portion of the roll shaft 31a of the belt meandering correction roll 31, and the belt meandering correcting member 58 includes: a first surface 58a which receives the first pressurizing force a and the correcting force e from the side edge 33a of the roll lying part of the intermediate transfer belt; and a second surface 58b which receives the roll oscillating force b and the second pressurizing force d from the force conversion member 52. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a belt meandering correction mechanism and an image forming apparatus.

  As a conventional belt meandering correction mechanism, there is one provided with a pair of rolls that circulate a belt so that the belt can run, and a bushing as a belt meandering correction member that is relatively non-rotatable to one of the pair of rolls. (For example, refer to Patent Document 1).

  In the pair of rolls, one roll is formed by a driving roll and the other roll is formed by a driven roll. The bush has a spiral end surface that presses the side edge of the belt on the belt side, and is attached to the driven roll among the drive roll and the driven roll.

  With the above configuration, when the drive roll is driven to rotate, the belt travels while being stretched over the drive roll and the driven roll. Even if there is meandering in the so-called belt that moves in the width direction by the running of the belt, the spiral end face presses the side edge of the belt in accordance with the rotation of the bush, so that the meandering of the belt is corrected.

JP 2007-86267 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a belt meandering correction mechanism and an image forming apparatus capable of suppressing the occurrence of belt wear due to pressing on a belt meandering correction member.

  In order to achieve the above object, one aspect of the present invention provides the following belt meandering correction mechanism and image forming apparatus.

[1] A base having a force converting portion that receives a pressing force caused by meandering of the belt and converts it into a roll swinging force, and a plurality of rolls that are rotatably arranged on the base and over which the belt can run. The plurality of rolls include a belt meandering correction roll that swings in response to the roll swinging force from the force converting portion of the base and returns by receiving a roll return force, and the belt meandering correction roll A belt meandering correction member for correcting the meandering of the belt is disposed at at least one end of the roll shaft, and the belt meandering correction member extends in a direction crossing the end face of the roll so as to roll the belt. A belt snake provided with a first surface that receives a pressing force due to meandering of the belt from a side edge of the transfer portion and a second surface that receives the roll swinging force from the force conversion portion of the base. Correction mechanism.

[2] The belt meandering correction roll is disposed on the base so as not to be movable in the axial direction thereof, and the belt meandering correction member is held on the roll shaft so as not to be relatively rotatable and movable. Belt meandering correction mechanism.

[3] The belt meandering correction roll according to [1], wherein the belt meandering correction member is formed by a moving member having the first surface as a plane or a curved surface and the second surface as a plane. Belt meander correction mechanism.

[4] The belt meandering correction roll includes a rotating part in which the belt meandering correction member rotates about an axis inclined with respect to the roll axis, and a holding part that rotatably holds the rotating part. The belt meandering correction mechanism according to [1], wherein the belt meandering correction mechanism is formed of a member, the rotating portion has the first surface formed of a flat surface, and the holding portion includes the second surface formed of a conical surface.

[5] The belt meandering correction mechanism according to [4], wherein the belt meandering correction roll has a movement restricting portion that restricts movement of the belt meandering correction member toward the belt.

[6] The belt meandering correction mechanism according to [1], wherein a part of the roll restoring force is always applied to the belt meandering correction roll by belt tension applying means for applying tension to the belt.

[7] An image forming unit that forms an image on a sheet, an intermediate transfer belt to which a toner image formed by the image forming unit is transferred, and a belt meandering correction mechanism that corrects the meandering of the intermediate transfer belt. The image forming apparatus, wherein the belt meandering correction mechanism is the belt meandering correction mechanism according to any one of [1] to [6].

  According to the first to third aspects of the present invention, the belt meandering correction member receives the first pressing force due to the meandering of the belt from the side edge of the belt overhanging portion of the belt and suppresses the occurrence of belt wear. Can do.

  According to the fourth and fifth aspects of the present invention, it is possible to rotate the rotating portion of the belt meandering correction member by pressing due to the running of the belt, and the roll roll portion side edge of the belt and the first surface of the rotating portion Belt wear due to frictional force generated during

  According to the sixth aspect of the present invention, no dedicated return means is required as the swing return means of the belt meandering correction member, and the number of parts can be reduced.

  According to the seventh aspect of the present invention, the belt meandering correction member receives the first pressing force due to the meandering of the intermediate transfer belt on the first surface from the roll transfer portion side edge of the intermediate transfer belt, and the intermediate transfer belt is worn. Can be suppressed.

FIG. 1 is a cross-sectional view for explaining an image forming apparatus to which a belt meandering correction mechanism according to a first embodiment of the present invention is applied. FIG. 2 is a perspective view for explaining the belt meandering correction mechanism according to the first embodiment of the present invention. FIG. 3 is a perspective view for explaining a main part of the belt meandering correction mechanism according to the first embodiment of the present invention. FIG. 4 is a side view for explaining the main part of the belt meandering correction mechanism according to the first embodiment of the present invention. FIG. 5 is a perspective view showing an arrangement state of the belt meandering correction member on the roll shaft in the belt meandering correction mechanism according to the first embodiment of the present invention. FIG. 6 is a perspective view for explaining a belt meandering correction member in the belt meandering correction mechanism according to the first embodiment of the present invention. FIG. 7 is a plan view showing an arrangement state of the belt meandering correction member on the roll shaft in the belt meandering correction mechanism according to the first embodiment of the present invention. FIG. 8 is a cross-sectional view taken along the line AA of FIG. FIGS. 9A, 9B and 9C are a plan view and a front view for explaining the operation of the belt meandering correction mechanism according to the first embodiment of the present invention. 9A is a plan view showing the normal belt running state, FIG. 9B is a front view showing the normal belt running state, and FIG. 9C is a front view showing the belt meandering state. Show. FIG. 10 is a side view schematically showing the operation of the roll support portion when roll swinging force or roll swinging return force is applied to the belt meandering correction roll. 11 (a) and 11 (b) are side views showing the belt contact area with respect to the belt meandering correction member of the belt meandering correction mechanism according to the first embodiment of the present invention in a simplified manner for comparison with the conventional example. is there. 11A shows the belt contact area of the present invention, and FIG. 11B shows the belt contact area of the conventional example. FIG. 12 is a perspective view showing an arrangement state of the belt meandering correction member on the roll shaft in the belt meandering correction mechanism according to the second embodiment of the present invention. FIG. 13 is a plan view showing an arrangement state of the belt meandering correction member on the roll shaft in the belt meandering correction mechanism according to the second embodiment of the present invention. 14 is a cross-sectional view taken along the line BB in FIG. FIG. 15 is an exploded perspective view for explaining a belt meandering correction member in the belt meandering correction mechanism according to the second embodiment of the present invention.

[First embodiment]
First, an image forming apparatus according to a first embodiment of the present invention will be described with reference to FIG.
FIG. 1 schematically shows an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 10 is a digital color printer, for example, and includes a housing 11 that incorporates an image processing unit (not shown). Then, image data transmitted from a host device such as a personal computer is subjected to image processing by an image processing unit (not shown) and image data for each color of yellow (Y), magenta (M), cyan (C), and black (K). After the conversion to, a color image is formed on the paper based on the image data of each color.

  A paper feed tray 12 that accommodates paper P as a recording medium is detachably disposed at a lower portion in the housing 10. A paper discharge unit 13 for discharging the recorded paper P is disposed in the upper part of the housing 10. In addition, a paper conveyance path 14 extending from the paper feed tray 12 to the paper discharge unit 13 is formed in the housing 11. A pickup roll 14 a that takes in the paper P from the paper feed tray 12 to the paper transport path 14 one by one in the paper transport path 14, and a transport roll that transports one sheet of paper while preventing the paper P from being overlapped and transported. A pair 14b, a correction roll pair 14c that corrects the skew of the paper P, a fixing roll 14d that fixes the toner image secondarily transferred to the paper P, and a paper P on which the toner image is fixed by the fixing roll 14d. A discharge roll 14e for discharging to 13 is disposed.

  An image forming unit 20 that forms an image on the paper P is disposed in the center of the housing 11. In the vicinity of the image forming unit 20, a drive roll 30, a belt meandering correction roll 31, and a driven roll 32 are arranged. An endless intermediate transfer belt 33 that circulates (runs) in the direction of the arrow in the drawing is stretched around these rolls 30 to 32. Photoconductors 22Y, 22M, 22C, and 22K as rotated bodies for forming toner images for the respective colors Y, M, C, and K while rotating in the direction of the arrows in the drawing are provided outside the intermediate transfer belt 33. The image forming units 21Y, 21M, 21C, and 21K having the above are detachably arranged at a certain interval in the belt traveling direction. Inside the intermediate transfer belt 33, primary transfer rolls 26Y, 26M, 26C, and 26K that transfer the toner images formed on the surfaces of the photoreceptors 22Y, 22M, 22C, and 22K to the intermediate transfer belt 33 are rotatably disposed. ing. The belt meandering correction roll 31 constitutes a belt meandering correction mechanism for correcting the meandering of the intermediate transfer belt 33 together with the driving roll 30 and the driven roll 32. Details of the belt meandering correction mechanism will be described later.

  The image forming units 21Y, 21M, 21C, and 21K are configured in the same manner, and the above-described photoreceptors 22Y, 22M, 22C, and 22K and chargers that uniformly charge the surfaces of the photoreceptors 22Y, 22M, 22C, and 22K. 23, and developing the electrostatic latent image formed by the exposure device 27 on the surface of the photoconductors 22Y, 22M, 22C, and 22K with toner, thereby forming toner images on the surfaces of the photoconductors 22Y, 22M, 22C, and 22K. A developing unit 24 and a photoconductor cleaning unit 25 that collects toner remaining on the surfaces of the photoconductors 22Y, 22M, 22C, and 22K are provided.

  The developing device 24 includes a housing 24a that stores toner therein. In the housing 24a, toner is supplied to the photoconductors 22Y, 22M, 22C, and 22K, and the electrostatic latent images on the photoconductors 22Y, 22M, 22C, and 22K are developed with toner, and the development roll 24b A supply auger 24c for supplying toner and a stirring auger 24d for stirring toner and supplying toner to the supply auger 24c are arranged. The developing device 24 is configured to receive toner of each color from the toner boxes 35Y, 35M, 35C, and 35K.

  The exposure unit 27 includes four semiconductor lasers (not shown) that emit laser light modulated with image data of each color of Y, M, C, and K, a polygon mirror 27a that branches the laser light emitted from each semiconductor laser, A plurality of mirrors 27b that reflect the laser beam branched by the polygon mirror 27a and irradiate the photoreceptors 22Y, 22M, 22C, and 22K to form electrostatic latent images on the surfaces of the photoreceptors 22Y, 22M, 22C, and 22K; And is sealed by a frame 27c so as not to get dirty with toner or the like. The upper part of the frame 27c is made of, for example, transparent glass.

  The image forming unit 20 includes a secondary transfer roll 34 facing the drive roll 30 via the intermediate transfer belt 33, and the toner image on the intermediate transfer belt 33 is transferred onto the paper P in the nip region formed with the drive roll 30. Next transfer.

  The image forming unit 20 includes a belt cleaning unit 40 that is upstream of the image forming unit 21 </ b> Y and faces the belt meandering correction roll 31 with the intermediate transfer belt 33 interposed therebetween. The belt cleaning unit 40 is pressed toward the belt meandering correction roll 31 and scrapes off and collects the toner remaining on the intermediate transfer belt 33.

  Next, the belt meandering correction mechanism according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 2 shows the entire belt meandering correction mechanism. As shown in FIG. 2, the belt meandering correction mechanism 100 includes a base 50 as a mechanism main body, roll support portions 51 and 51 that support a belt meandering correction roll 31 (described later) at both ends, and a belt meandering correction roll 31. Rolls 30 to 32 (shown in FIG. 1) are provided, and are arranged in the casing 11 of the image forming apparatus 10 (shown in FIG. 1).

  The base 50 has a pair of side wall portions 50a, 50a facing each other and a plurality of connecting portions (not shown) for connecting the pair of side wall portions 50a, 50a, and the whole is provided via a roll support portion 51. Thus, it is formed as a substantially square frame-shaped support member that rotatably supports the rolls 30 to 32. Force conversion members 52 and 52 (only one of them is shown) that are opposed to each other in the base 50 are attached to the side walls 50a and 50a. Further, spring locking tools 51a and 51a for locking a tension spring 53 as belt tension applying means for applying tension to the intermediate transfer belt 33 are arranged on the side walls 50a and 50a.

  FIG. 3 shows a state in which the main part of the belt meandering correction mechanism is viewed obliquely from the rear. As shown in FIG. 3, the force conversion member 52 has a contact portion 52 a having a semicircular cross section at the tip, and is disposed on the side of the intermediate transfer belt 33. Then, the first pressing force a due to the meandering of the intermediate transfer belt 33 is received and a part thereof is converted into the roll swinging force b, and the roll swinging return force c due to the pulling force of the tension spring 53 as a return means (FIG. 4). And a part thereof (a part of the second pressing force d by the roll swinging return force c) is converted into a correction force e for correcting the meandering of the intermediate transfer belt 33. As the material of the force conversion member 52, for example, a resin material such as fluororesin or polyethylene terephthalate (PET) resin, or a metal material such as aluminum (Al) or stainless steel is used.

  FIG. 4 shows a state in which the main part of the belt meandering correction mechanism is viewed from the side. As shown in FIG. 4, the roll support portion 51 (only one is shown) includes a link mechanism having a pair of links 55 and 56 that are slidably connected to each other via a connection pin 54. Arranged outside.

  One link 55 is held on the side wall portion 50 a of the base 50 so as to be swingable around the swing rotation pin 57. And it is comprised so that it may rock | fluctuate in the arrow m and n direction centering | focusing on the rocking | swiveling rotation pin 57. FIG. The link 55 is provided with a spring locking portion 55a in which the other end of the tension spring 53 locked in the spring locking tool 51a is locked.

The other link 56 is, for example, a connecting pin at a position where the tension of the intermediate transfer belt 33 acting via the belt meandering correction roll 31 (roll shaft 31a) and the tensile force of the tension spring 53 acting on one link 55 are balanced. 54 is disposed on an axis O ₂ that is substantially orthogonal to the axis O ₁ that connects the pin 54 and the rocking rotation pin 57. The free end of the link 56 (end opposite to the end of the connection pin 54 side), the support hole 56a (Fig for immovably supporting the roll shaft 31a of the belt meandering correction roller 31 in the axial O ₃ directions 3) is provided.

  The rolls 30 to 32 (shown in FIG. 1) have side walls 50a and 50a (shown in FIG. 2) of the base 50, and end portions of the roll shafts (not shown) of the drive roll 30 and the driven roll 32. The end portion of the roll shaft 31 a of the correction roll 31 is rotatably supported via the roll support portion 51.

  FIG. 5 shows the contact state of the intermediate transfer belt to the belt meandering correction roll as viewed obliquely from above. As shown in FIG. 5, the belt meandering correction roll 31 has a roll shaft 31 a on its axis, and is rotatable on side walls 50 a and 50 a of a base 50 (shown in FIG. 2) via a roll support 51. It is arranged so as not to move, and a tensile force (roll swing return force c) is constantly applied by a tension spring 53 (shown in FIG. 4).

  The belt meandering correction roll 31 receives the roll swinging force b from the force converting member 52 that has received the first pressing force a due to the meandering of the intermediate transfer belt 33 via the belt meandering correction members 58 and 58 (only one is shown). The spring is configured to swing against the tensile force of the tension spring 53 (shown in FIG. 4).

  The belt meandering correction roll 31 receives the belt running force from the intermediate transfer belt 33 as a roll swing return force, and also receives the roll swing return force c due to the tensile force of the tension spring 53 from the roll support portion 51 and swings. It is configured to return. As a result, the belt tension applying means (tensile spring 53) of the intermediate transfer belt 33 can be used as the swing return means of the belt meandering correction roll 31, and no dedicated swing return means is required, reducing the number of parts. be able to.

  FIG. 6 shows a belt meandering correction member. As shown in FIG. 6, the belt meandering correction members 58 and 58 (only one is shown) are held at each end of the roll shaft 31a of the belt meandering correction roll 31 (shown in FIG. 5) so as not to be relatively rotatable and movable. The whole is formed of a heptahedron having a first surface 58a to a seventh surface 58g having different surface areas. In response to the first pressing force a caused by the meandering of the intermediate transfer belt 33, the belt moves on the roll shaft 31a of the belt meandering correction roll 31 in the direction away from the intermediate transfer belt 33 (shown in FIG. 5), and the first pressing force a. A part of the pressure a is configured to act on the force conversion member 52 (shown in FIG. 5). As the belt meandering correction members 58 and 58, for example, a resin material such as fluororesin and polyethylene terephthalate (PET) resin, or a metal material such as aluminum (Al) or stainless steel is used. The dimension between the belt meandering correction members 58 and 58 is set to be larger than the dimension in the width direction of the intermediate transfer belt 33. The first surface 58a and the second surface 58b will be described later.

  The belt meandering correction member 58 is provided with a shaft insertion hole 58h that opens to the first surface 58a and the fifth surface 58e and through which the roll shaft 31a of the belt meandering correction roll 31 (shown in FIG. 5) is inserted.

  Further, the belt meandering correction member 58 receives the roll swing return force c of the tension spring 53 (shown in FIG. 4) and moves on the roll shaft 31a of the belt meandering correction roll 31 in the direction approaching the intermediate transfer belt 33. At the same time, a part (second pressing force d) of the roll swing return force c is applied to the force conversion member 52 (shown in FIG. 5).

FIG. 7 shows a state in which the intermediate transfer belt contacts the belt meandering correction roll as viewed from above. FIG. 8 shows a state in which the intermediate transfer belt is in contact with the belt meandering correction roll as seen from the upstream side of the belt. As shown in FIGS. 7 and 8, the first surface 58a is disposed at a position where the roll transfer portion side edge 33a can come into contact with the meandering of the intermediate transfer belt 33, and the first surface 58a is entirely inserted into the shaft insertion hole 58h (roll shaft 31a). (e.g. inclined with respect to the axis O ₃ of) the inclination angle α of the first surface 58a is ≒ 10 ° inclined α with respect to a plane perpendicular to the axis O ₃₎ is formed by rectangular planar. As a result, the belt meandering correction member 58 receives the first pressing force a due to the meandering of the intermediate transfer belt 33 from the roll transfer portion side edge 33a of the intermediate transfer belt 33 on the first surface 58a, and the intermediate transfer belt 33 is worn. Can be suppressed. The first surface 58a is configured to transmit and receive a correction force e in addition to the first pressing force a between the intermediate transfer belt 33 and the roll transfer portion side edge 33a.

In the present embodiment has described the case where the inclination angle alpha of the first surface 58a is set to an angle inclined alpha ≒ 10 ° with respect to a plane perpendicular to the axis O _3, the inclination angle of the first surface May be set to other angles. Moreover, although the case where the 1st surface 58a was formed in the plane was demonstrated, it may replace with a plane and may form the 1st surface with a curved surface.

The second surface 58b is disposed at a position for pressing the contact portion 52a of the force converting member 52, the whole is inclined with respect to the axis _{O 3} and first surface 58a of the shaft insertion hole 58h (e.g., slope of the second surface 58b (An angle β is inclined by β≈45 ° with respect to a plane orthogonal to the axis O ₃ ). And it is comprised so that the roll rocking | fluctuation force b and the 2nd pressing force d may be exchanged between the contact parts 52a of the force conversion member 52. FIG.

In the present embodiment has described the case where the inclination angle beta of the second surface 58b is set to an angle of inclination beta ≒ 45 ° with respect to a plane perpendicular to the axis O _3, the inclination angle of the second surface May be set to other angles.

  Next, the operation of the belt meandering correction mechanism according to the first embodiment of the present invention will be described with reference to FIGS. 9 (a) to 9 (c) and FIG. 9A and 9B show a normal running state of the intermediate transfer belt, and FIG. 9C shows a running state when the intermediate transfer belt meanders. FIG. 10 shows an operation state of the roll support portion when a roll swinging force or a roll swinging return force is applied to the belt meandering correction roll.

  As shown in FIGS. 9A and 9B, the intermediate transfer belt 33 snakes from the normal running state as shown in FIG. 9C, and the intermediate transfer belt 33 is rolled. When the transfer portion side edge 33a presses the first surface 58a of the one belt meandering correction member 58 with the first pressing force a, the belt meandering correction member 58 is the first surface 58a on the roll passing portion side edge of the intermediate transfer belt 33. A first pressing force a is received from 33a. In this case, when the belt meandering correction member 58 receives the first pressing force a on the first surface 58a, the belt meandering correction member 58 moves along the roll axis 31a of the belt meandering correction roll 31 in the direction away from the intermediate transfer belt 33, and the first surface 58a. A part of the pressing force a acts on the force conversion member 52 from the second surface 58b of the belt meandering correction member 58 via the contact portion 52a.

  In the force conversion member 52, the contact portion 52a receives a part of the first pressing force a from the second surface 58b of the belt meandering correction member 58 and converts it into a roll swinging force b. In this case, when a part of the first pressing force a is converted into the roll swinging force b by the force conversion member 52, the roll swinging force b is applied to the roll shaft 31 a of the belt meandering correction roll 31 via the belt meandering correction member 58. Is transmitted.

  Therefore, the roll shaft 31a of the belt meandering correction roll 31 is displaced in the direction indicated by the arrow s in FIG. The belt meandering correction roll 31 swings against the tensile force of the tension spring 53.

  Accordingly, the link 56 of the roll support portion 51 swings from the position shown by the solid line in FIG. 10 by displacing the connecting pin 54 as shown by the two-dot chain line in FIG. Then, the link 55 swings from the position indicated by the solid line in FIG. 10 around the swing rotation pin 57 as indicated by the two-dot chain line in FIG.

  On the other hand, when the first pressing force a applied to the belt meandering correction member 58 due to the meandering of the intermediate transfer belt 33 is released, the tensile force of the tension spring 53 acts on the link 55 of the roll support portion 51. Then, the link 55 swings and returns from the position shown by the two-dot chain line in FIG. 10 around the swinging rotation pin 57 as shown by the solid line in FIG. 56 swings back from the position indicated by the two-dot chain line in FIG. 10 as indicated by the solid line in FIG.

  Accordingly, the roll shaft 31a of the belt meandering correction roll 31 is displaced in the direction indicated by the arrow t in FIG. 10, and the in-plane substantially orthogonal to the swing surfaces of the links 55 and 56 and the inter-roll running surface of the intermediate transfer belt 33. Then, the belt meandering correction roll 31 is returned to the swinging state by the roll swinging return force c due to the tensile force of the tension spring 53.

  Therefore, the belt meandering correction member 58 moves along the roll shaft 31a of the belt meandering correction roll 31 in the direction approaching the intermediate transfer belt 33, and the second pressing force d (see FIG. 8) due to the roll swing return force c. 2) acts on the force conversion member 52 from the second surface 58b of the belt meandering correction roll 31 via the contact portion 52a.

  In the force conversion member 52, the contact portion 52 a receives the second pressing force d from the second surface 58 b of the belt meandering correction member 58 and converts it into a correction force e that corrects the meandering of the intermediate transfer belt 33.

  9C, the belt meandering correction roll 31 receives the roll swinging force b from the contact surface 52a of the force conversion member 52, and swings and tilts with respect to the drive roll 30. In addition to the roll rocking return force c due to the tensile force of the tension spring 53, the belt running force of the intermediate transfer belt 33 due to the rotation of the drive roll 30 acts on the belt meandering correction roll 31 as the roll rocking return force. For this reason, when the belt meandering correction roll 31 receives the roll swing return force c and the belt travel force and returns to swing, the intermediate transfer belt 33 moves in the direction from the meandering position toward the center in the roll width direction. Part of the force toward the roll 30 is received.

  As a result, the span of the intermediate transfer belt 33 with respect to the belt meandering correction roll 31 is displaced from the meandering position to the center position in the roll width direction, and the meandering of the intermediate transfer belt 33 is automatically corrected.

  FIGS. 11A and 11B show a comparison between the present invention and the conventional example in the belt contact region with respect to the belt meandering correction member.

  In the present embodiment, as shown in FIG. 11A, the first pressing force a due to meandering of the intermediate transfer belt 33 is applied to the first surface 58a of the belt meandering correction member 58 by the roll transfer portion of the intermediate transfer belt 33. Since it acts via the side edge 33a, the belt width direction drag against the belt meandering correction member 58 of the intermediate transfer belt 33 is increased. As a result, even if the intermediate transfer belt 33 presses the belt meandering correction member 58 by meandering, it is difficult for wear to occur at the bridging portion side edge 33a, and breakage of the intermediate transfer belt 33 is suppressed.

  On the other hand, according to the conventional belt meandering correction mechanism, as shown in FIG. 11B, the pressing force due to the meandering of the intermediate transfer belt 60 is not limited to the roll transfer portion side edge 60a of the intermediate transfer belt 60. The belt meandering correction member 61 (for example, the flat bottom surface of the conical member in FIG. 11B) acts on the belt meandering side edge 60b, 60b continuous with the roll spanning part side edge 60a. The belt width direction drag of the belt 60 against the belt meandering correction member 61 is small. Accordingly, when the intermediate transfer belt 60 presses the belt meandering correction member 61 by meandering, wear occurs on the belt flat portion side edges 60b and 60b, and the intermediate transfer belt 60 is easily broken by repetition of this wear.

[Second Embodiment]
Next, a belt meandering correction mechanism according to a second embodiment of the present invention will be described with reference to FIGS. 12 to 15, members that are the same as or equivalent to those in FIG. 5 are given the same reference numerals, and detailed descriptions thereof are omitted.

FIG. 12 shows the contact state of the intermediate transfer belt to the belt meandering correction roll as viewed obliquely from above. FIG. 13 shows a state in which the intermediate transfer belt is in contact with the belt meandering correction roll as viewed from above. FIG. 14 shows a state in which the belt meandering correction member is held on the roll shaft. FIG. 15 shows a belt meandering correction member. As shown in FIGS. 12 to 14, in the belt meandering correction mechanism 200 (components such as the base 50 are omitted) according to the second embodiment of the present invention, the belt meandering correction member 201 is provided on the belt meandering correction roll 31. It is formed by a moving member having a rotating part 202 that rotates around an axis O ₄ inclined with respect to the axis O ₃ of the roll shaft 31 a and a holding part 203 that rotatably holds the rotating part 202. There is.

  For this reason, the rotating unit 202 has a first surface 202a composed of a plane for transmitting and receiving the first pressing force a and the correction force e to and from the transfer portion side edge 33a of the intermediate transfer belt 33, and is entirely annular. It is formed by a rotating plate. Accordingly, the rotation portion 202 of the belt meandering correction member 201 can be rotated by the pressure generated by the travel of the intermediate transfer belt 33, and the roll transfer portion side edge 33a of the intermediate transfer belt 33 and the first surface 202a of the rotation portion 202 are rotated. It is possible to suppress the occurrence of wear of the intermediate transfer belt 33 due to the frictional force generated between the two.

  The holding unit 203 has a second surface 203a that receives and transmits the roll swinging force b and the second pressing force d with the force conversion member 52, and has a base portion 204 having a truncated cone shape and a disc-like convex portion as a whole. 205.

The holding portion 203 has a shaft insertion hole 203b which opens along the axis _{O 3,} and a keyway 203c communicating with the shaft insertion hole 203b. The belt meander correction roll 31 is held on a roll shaft 31 a via a key 206 so as not to be relatively rotatable and movable.

  The key 206 is interposed between the holding unit 203 and the roll shaft 31a and between the roll support unit 50 (link 56) and the roll shaft 31a. Therefore, the link 56 is provided with a key groove 56b communicating with the support hole 56a, and the roll shaft 31a is provided with a key groove 310a opened on the outer peripheral surface thereof. As a result, one end of the key 206 is in the key groove 203c of the holding portion 203 and the key groove 310a of the roll shaft 31a, and the other end is in the key groove 56b of the link 56 and the key groove 310a of the roll shaft 31a. Mated.

  Further, as shown in FIG. 15, the belt meandering correction member 201 has a movement restricting portion 207 that restricts the movement of the rotating portion 202 toward the intermediate transfer belt 33 (shown in FIG. 14).

  The movement restricting portion 207 includes a shaft insertion hole 207a for inserting the roll shaft 31a of the belt meandering correction roll 31 (shown in FIG. 14), and a screw insertion hole 207b for inserting fixing screws 208 and 208 (shown in FIG. 14). , 207b, and the whole is formed of a disk member.

  In the belt meandering correction mechanism 200 configured as described above, the first pressing force a caused by meandering on the intermediate transfer belt 33 is applied to the first surface 202a of the rotating unit 202 via the roll transfer part side edge 33a of the intermediate transfer belt 33. Therefore, even if the intermediate transfer belt 33 presses the belt meandering correction member 201 by meandering, it is difficult for the roll transfer portion side edge 33a to wear, and the intermediate transfer belt 33 is prevented from being broken.

  The image forming apparatus (belt meandering correction mechanism) of the present invention has been described above based on the above embodiment, but the present invention is not limited to the above embodiment and is within the scope not departing from the gist thereof. The present invention can be implemented in various modes, and for example, the following modifications are possible.

(1) In each of the above-described embodiments, the case where the belt meandering correction members 58 and 58 are respectively disposed at one end and the other end of the roll shaft 31a of the belt meandering correction roll 31 has been described. The present invention is not limited to this, and even if a belt meandering correction member is disposed at one end of the roll shaft of the belt meandering correction roll, the intended purpose of suppressing belt wear can be achieved.

(2) In each of the above embodiments, the case where the belt meandering correction roll 31 (roll shaft 31a) is disposed so as to be immovable via the roll support portion 51 on the base 50 has been described. It is not limited, You may arrange | position the roll axis | shaft of a belt meandering correction | amendment roll so that a movement is possible with respect to a base. In this case, the belt meandering correction member is disposed on the roll shaft of the belt meandering correction roll so as not to rotate and to move.

(3) In each of the above embodiments, the case where the intermediate transfer belt 33 is used as the belt has been described. However, the present invention is not limited to this, and other belts such as a paper transport belt for transporting paper may be used. Good.

(4) In each of the above-described embodiments, the case where the present invention is applied to a printer has been described. However, the present invention is not limited to this, and may of course be applied to a copying machine or a facsimile, such as a copying machine, a printer, and a facsimile. You may apply to the multi-function machine which combines two at least.

(5) In each of the above embodiments, the case where the image forming apparatus 100 is a color image forming apparatus using a plurality of photoconductors 22Y, 22M, 22C, and 22K has been described. However, the present invention is not limited to this. A monochrome image forming apparatus using a single photoconductor may be used.

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 11 ... Housing | casing, 12 ... Paper feed tray, 13 ... Paper discharge part, 14 ... Paper conveyance path, 14a ... Pickup roll, 14b ... Correction roll, 14c ... Conveyance roll, 14d ... Fixing roll, 14e DESCRIPTION OF REFERENCE SIGNS ... Ejecting roll, 20 ... Image forming unit, 21Y, 21M, 21C, 21K ... Image forming unit, 22Y, 22M, 22C, 22K ... Photoconductor, 23 ... Charging device, 24 ... Developer, 24a ... Housing, 24b ... Developing Roll, 24c ... Supply auger, 24d ... Stirrer auger, 25 ... Photoconductor cleaning unit, 26Y, 26M, 26C, 26K ... Primary transfer roll, 27 ... Exposure unit, 27a ... Polygon mirror, 27b ... Mirror, 27c ... Frame, 30 ... Driving roll, 31 ... Belt meandering correction roll, 31a ... Roll shaft, 310a ... Key groove, 32 ... Following roll, 33 Intermediate transfer belt, 33a ... Rolling edge side edge, 34 ... secondary transfer roll, 35Y, 35M, 35C, 35K ... toner box, 40 ... belt cleaning part, 50 ... base, 50a ... side wall part, 51 ... roll support Part, 51a ... spring locking tool, 52 ... force conversion member, 52a ... contact part, 53 ... tension spring, 54 ... connecting pin, 55 ... link, 55a ... spring locking part, 56 ... link, 56a ... keyway, 57 ... Oscillating rotation pin, 58 ... Belt meandering correction member, 58a to 58g ... First surface to seventh surface, 58h ... Shaft insertion hole, 100 ... Belt meandering correction mechanism, 200 ... Belt meandering correction mechanism, 201 ... Belt meandering Correction member 202... Rotating part 202a... First surface 203. Holding part 203 a second surface 203 b Shaft insertion hole 203 c Key groove 204 207a ... Shaft insertion hole, 207b ... Screw insertion hole, 208 ... Screw, a ... First pressing force, b ... Roll rocking force, c ... Roll rocking dynamic return force, d ... second pressing force, e ... correction _{force, O} 1 _~O 4 _... axis, P ... paper

Claims (7)

A base having a force conversion unit that receives a pressing force caused by meandering of the belt and converts it into a roll swinging force;
A plurality of rolls arranged rotatably on the base and over which the belt can run;
The plurality of rolls include a roll for belt meandering correction that swings by receiving the roll swinging force from the force converting portion of the base and that returns by receiving a roll return force,
In the belt meandering correction roll, a belt meandering correction member for correcting the meandering of the belt is disposed at an end of at least one side of the roll shaft, and the belt meandering correction member extends in a direction intersecting the roll end surface. A belt that is provided with a first surface that extends and receives a pressing force due to meandering of the belt from a side edge of the roll span portion of the belt, and a second surface that receives the roll swinging force from the force conversion portion of the base. Meander correction mechanism.   2. The belt meandering correction according to claim 1, wherein the belt meandering correction roll is disposed on the base so as not to move in an axial direction thereof, and the belt meandering correction member is held on the roll shaft so as not to be relatively rotatable and movable. mechanism.   2. The belt meandering correction mechanism according to claim 1, wherein the belt meandering correction roll is formed by a moving member having the first surface as a flat surface or a curved surface and the second surface as a flat surface. .   The belt meandering correction roll is formed by a moving member having a rotating part in which the belt meandering correcting member rotates about an axis inclined with respect to the roll axis, and a holding part for rotatably holding the rotating part. 2. The belt meandering correction mechanism according to claim 1, wherein the rotating portion has the first surface made of a flat surface, and the holding portion has the second surface made of a conical surface.   The belt meandering correction mechanism according to claim 4, wherein the belt meandering correction roll includes a movement restricting portion that restricts the movement of the belt meandering correcting member toward the belt.   2. The belt meandering correction mechanism according to claim 1, wherein a part of the roll restoring force is constantly applied to the belt meandering correction roll by belt tension applying means for applying tension to the belt. An image forming apparatus comprising: an image forming unit that forms an image on a sheet; an intermediate transfer belt to which a toner image formed by the image forming unit is transferred; and a belt meandering correction mechanism that corrects meandering of the intermediate transfer belt The image forming apparatus according to claim 1, wherein the belt meandering correction mechanism is a belt meandering correction mechanism according to claim 1.

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