JP2005036884A - Bearing, its mounting structure and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a cost increase after changing the outer diameter of a transfer roller. <P>SOLUTION: A center P1 of the inner diameter of a bearing 72 for the transfer roller 70 whose outer diameter is changed is shifted a preset distance Q from a center P2 of the outer diameter thereof. So, a guide 62 can be moved to such a position as before changing the outer diameter of the transfer roller 70 after transfer without changing the shape of a unit housing 58, etc. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a bearing, a bearing mounting structure, and an image forming apparatus.

  In image forming apparatuses such as printers and copiers, rotation functional members such as transfer rollers and fixing rollers, unit housings such as transfer units and fixing units, and important functional parts such as post-transfer guides and thermistors attached to the unit housings The positional relationship with is important.

  This positional relationship is affected by the size and mounting position of the bearing that rotatably mounts the rotary function member on the unit housing. Usually, a cylindrical body, a ball bearing, or the like is used as this bearing (for example, see Patent Documents 1 to 3).

However, in the conventional bearing, when the outer diameter of the rotation function member is changed, the shape of the unit housing needs to be changed in order to maintain the positional relationship in the state before the outer diameter change of the rotation function member. There was a problem that the cost would be greatly increased.
JP-A-5-197305 JP-A-11-344849 Japanese Patent Laid-Open No. 11-24504

  The present invention has been made in consideration of the above facts, and an object of the present invention is to make it possible to adjust the positional relationship between a rotary function member and an important functional component only by changing the bearing when changing the outer diameter of the rotary function member. And

  The bearing according to claim 1 is a bearing that rotatably supports the shaft, wherein the center of the inner diameter is eccentric by a predetermined amount with respect to the center of the outer diameter.

  In the bearing according to claim 1, the center of the inner diameter is eccentric by a predetermined amount with respect to the center of the outer diameter. For this reason, when the bearing of the present invention is used in place of a normal bearing in which the center of the inner diameter is aligned with the center of the outer diameter, the position of the shaft center moves by a predetermined amount, or the bearing is attached. The position of the part moves by a predetermined amount.

  As a result, when the outer diameter of the shaft is changed, the positional relationship between the shaft and the parts provided around the shaft can be adjusted without changing the shape of the parts to which the bearings are attached. Can be prevented.

  The bearing according to claim 2 is a bearing that rotatably supports the shaft, wherein the center of the inner diameter is eccentric by a predetermined amount with respect to the center of the mounting portion.

  In the bearing according to claim 2, the center of the inner diameter is eccentric with respect to the center of the mounting portion. Here, the attachment portion is a portion attached to a housing or the like of the bearing, and in the case of a bearing having a circular outer shape, it is a circular outer peripheral surface, and the center is the center of the circle. In the case of a bearing having a rectangular outer shape, it is a rectangular outer peripheral surface, and the center is an intersection of two diagonal lines. Further, when the outer shape is a polygon such as a hexagon, it is the outer peripheral surface of the polygon, and the center is an intersection of three or more diagonal lines.

  The bearing mounting structure according to claim 3 is a bearing mounting structure comprising a bearing that rotatably supports a shaft, and a mounting member to which the bearing is mounted. An engaging portion formed on the bearing or the mounting member, and an engaged portion formed on the mounting member or the bearing and engaged with the engaging portion. At least one is provided in a plurality in the circumferential direction of the shaft.

  In the bearing mounting structure according to claim 3, the engaging portion formed on the bearing or the mounting member engages with the engaged portion formed on the mounting member or the bearing, so that the bearing is mounted on the mounting member. . In the bearing, the center of the inner diameter is eccentric by a predetermined amount with respect to the center of the outer diameter. A plurality of engaging portions and engaged portions are provided in the circumferential direction of the shaft.

  For this reason, the direction which attaches a bearing to an attachment member can be selected. And the position of the axial center of a shaft with respect to an attachment member can be adjusted in steps by the direction which attaches a bearing to an attachment member. As a result, the positional relationship between the shaft and the components around the shaft can be adjusted in stages, so that there is room for reducing the required degree of dimensional accuracy of the components around the shaft and the mounting member. In addition, since the positional relationship between a plurality of types of shafts having different outer diameters and parts around the shafts can be maintained at a predetermined value, the shape of the mounting member can be changed when the outer diameter of the shaft is changed. There is no need to change, and there is no need to change the bearing. Therefore, an increase in cost can be prevented.

  5. The image forming apparatus according to claim 4, wherein the first rotation function member, the second rotation function member that nips and conveys the first rotation function member and the image forming medium, and the second rotation function member are rotatable. And a bearing in which the center of the inner diameter is eccentric by a predetermined amount with respect to the center of the outer diameter, and a mounting member to which the bearing is mounted.

  5. The image forming apparatus according to claim 4, wherein the second rotation functional member such as a transfer roller rotatably supported by a bearing and the first rotation functional member such as an intermediate transfer drum nip and convey the image forming medium. . In this bearing, the center of the inner diameter is eccentric by a predetermined amount with respect to the center of the outer diameter. For this reason, when the bearing of the present invention is used in place of a normal bearing whose center of the inner diameter is aligned with the center of the outer diameter, the position of the axis of the second rotational function member moves by a predetermined amount, or the bearing The position of the attached mounting member moves by a predetermined amount.

  Thus, when the outer diameter of the second rotation function member is changed, the second rotation function member and the second rotation function member are provided around the second rotation function member without changing the shape of the mounting member to which the bearing is attached. Since the positional relationship with parts such as a conveyance guide can be adjusted, an increase in cost can be prevented.

  An image forming apparatus according to claim 5 is the image forming apparatus according to claim 4, wherein the image forming apparatus is formed on the bearing or the mounting member, and is formed on the mounting member or the bearing. A plurality of engaged portions that engage with the engaging portions are provided in the circumferential direction.

  In the image forming apparatus according to the fifth aspect, the engaging portion formed on the bearing or the mounting member and the engaged portion formed on the mounting member or the bearing are engaged to attach the bearing to the mounting member. In the bearing, the center of the inner diameter is eccentric by a predetermined amount with respect to the center of the outer diameter. In addition, at least one of the engaging portion and the engaged portion is provided in a plurality in the circumferential direction of the second rotation function member.

  For this reason, the direction which attaches a bearing to an attachment member can be selected. And the position of the axial center of the 2nd rotation functional member with respect to an attachment member can be adjusted in steps by the direction which attaches a bearing to an attachment member. As a result, the positional relationship between the second rotation function member and the peripheral parts of the second rotation function member such as the transport guide can be adjusted in stages, so that the required degree of dimensional accuracy of the parts such as the transport guide and the mounting member can be increased. There is room for lowering.

  In addition, since the positional relationship between a plurality of types of second rotation function members having different outer diameters and parts such as the conveyance guide can be maintained at a predetermined value, the outer diameter of the second rotation function member is changed. In addition, there is no need to change the shape of the mounting member, and there is no need to change the bearing. Therefore, an increase in cost can be prevented.

  An image forming apparatus according to a sixth aspect is the image forming apparatus according to the fourth or fifth aspect, wherein the second rotation function member uses the image forming medium as an image carrier as the first rotation function member. A transfer roller that presses and transfers an image formed on the image carrier to the image forming medium, and a guide unit that guides conveyance of the image forming medium after the image is transferred is provided on the attachment member; The positional relationship between the guide means and the nip portion between the transfer roller and the image carrier is adjusted by changing the amount of eccentricity of the bearing.

  In the image forming apparatus according to the sixth aspect, the image forming medium is pressed against the image carrier by the transfer roller, and the image on the image carrier is transferred to the image forming medium. Then, the image forming medium after the image is transferred is guided to be conveyed by guide means provided on the attachment member.

  The positional relationship between the guide means and the nip portion between the transfer roller and the image carrier depends on a bearing that rotatably supports the transfer roller. If this positional relationship is not a predetermined relationship, the image forming medium A jam may occur due to the tip of the hook being caught by the guide means. In particular, when the outer diameter of the transfer roller is reduced, the guide means approaches the contact point between the transfer roller and the image carrier, and the leading edge of the image forming medium is easily caught by the guide means.

  However, the positional relationship can be adjusted by changing the amount of eccentricity of the bearing, and the position of the shaft center of the transfer roller can be moved by a predetermined amount, or the position of the component to which the bearing is attached can be moved by a predetermined amount.

  As a result, the guide means can be separated from the nip portion between the transfer roller and the image carrier without changing the shape of the component to which the bearing is attached, and the leading edge of the image forming medium can be prevented from being caught by the guide means. .

  The image forming apparatus according to claim 7 is the image forming apparatus according to claim 5 or 6, wherein the transfer roller and the image carrier are changed by changing a mounting position of the bearing in a circumferential direction with respect to the mounting member. The positional relationship between the nip portion and the guide means is adjusted.

  In the image forming apparatus according to the seventh aspect, the positional relationship between the guide unit and the nip portion between the transfer roller and the image carrier is adjusted by changing the mounting position of the bearing in the circumferential direction with respect to the mounting member. For this reason, a margin for reducing the required degree of dimensional accuracy of the guide means and the mounting member is created.

  Further, since it is possible to cope with a plurality of types of transfer rollers having different outer diameters, it is not necessary to change the shape of the mounting member and to change the bearings when the outer diameter of the transfer roller is changed. Therefore, an increase in cost can be prevented.

  Since the present invention has the above-described configuration, when changing the outer diameter of the shaft rotatably supported by the bearing, the second rotation function member, and the transfer roller, the shaft and the peripheral parts of the shaft, the second rotation function member, The positional relationship between the peripheral parts of the second rotation functional member and the nip portion between the transfer roller and the image carrier and the guide means can be adjusted only by changing the bearing.

  Further, the positional relationship between the shaft and the peripheral components of the shaft, the positional relationship between the second rotational function member and the peripheral components of the second rotational functional member, and the nip portion between the transfer roller and the image carrier and the guide means Since the positional relationship can be adjusted in stages, there is a room for reducing the required degree of dimensional accuracy of each part. And it becomes possible to cope with a plurality of types of shafts, second rotation function members, and transfer rollers having different outer diameters. When the outer diameters of the shaft, second rotation function member, and transfer roller are changed, the bearings and the bearings It is not necessary to change the shape of the parts to be installed. Therefore, an increase in cost can be prevented.

  The first embodiment will be described below with reference to the drawings.

  As shown in FIG. 1, a color laser printer (hereinafter referred to as a printer) 10 as an image forming apparatus includes plain paper, recycled paper, or an OHP sheet (hereinafter referred to as paper P) as an image forming medium. A print head device 12 for forming a full color image is provided.

  The print head device 12 includes four photosensitive drums 14Y, 14M, 14K, and 14C, and the printer 10 transmits a light beam to the four photosensitive drums 14Y, 14M, 14K, and 14C. An optical scanning device 16 that scans to form a latent image is provided.

  The print head device 12 is provided with four developing devices 18Y, 18M, 18K, and 18C that individually develop the latent images formed on the four photosensitive drums 14Y, 14M, 14K, and 14C. The printer 10 includes four toner boxes 20Y for supplying yellow (Y), magenta (M), black (K), and cyan (C) toners to the developing devices 18Y, 18M, 18K, and 18C, respectively. 20M, 20K, and 20C are provided.

  Further, the printer 10 includes a paper feed cassette 22 that stores the paper P that is conveyed to the transfer unit of the print head device 12, and a manual paper feed tray 24 that supplies the paper P from the outside to the transfer unit of the print head device 12. Is provided.

  Further, the printer 10 includes a fixing device 26 that performs a fixing process on the paper P on which the toner image is transferred by the print head device 12, and the print head device by reversing the front and back of the paper P on which the toner image is fixed. A transport device 28 for double-sided printing that transports again to a transfer unit 12; a controller 30 that includes a control circuit that controls the operation of the printer; an image processing circuit that performs image processing on image signals; and an electric circuit that includes a high-voltage power supply circuit 32 and a discharge tray 34 for stocking the paper P on which an image has been formed and discharged.

  As shown in FIG. 2, the optical scanning device 16 is lit and driven based on image data of each color of Y, M, K, and C, and has four laser beams corresponding to each color of Y, M, K, and C. And a polygon mirror that deflects and scans four laser beams emitted from the semiconductor laser 36 onto the photosensitive drums 14Y, 14M, 14K, and 14C, an f-θ lens, a reflection mirror, and the like. An optical unit 38 is provided.

  In addition, the print head device 12 includes a developing unit 18 including four developing devices 18Y, 18M, 18K, and 18C, a photosensitive unit 14 including four photosensitive drums 14Y, 14M, 14K, and 14C, and a photosensitive unit. 14 includes an intermediate transfer body unit 40 that conveys the toner image formed on the paper 14 to the paper P.

  The intermediate transfer unit 40 contacts the photosensitive drums 14Y and 14M and contacts the first primary intermediate transfer drum 40A on which the toner images of two colors Y and M are transferred and the photosensitive drums 14K and 14C. The second primary intermediate transfer drum 40B, the first primary intermediate transfer drum 40A, the second primary intermediate transfer drum 40B, and the transfer roller 48 to which toner images of two colors K and C are transferred in an overlapping manner are transferred to the transfer roller 48. A secondary transfer drum (image carrier) 40C is provided in which the toner images of four colors Y, M, K, and C are transferred in contact with each other and transferred onto the paper P, and the toner images superimposed on the four colors are transferred. .

  The photosensitive drums 14Y, 14M, 14K, and 14C are not transferred to the charging rolls 42Y, 42M, 42K, and 42C for primary charging, the first primary intermediate transfer drum 40A, and the second primary intermediate transfer drum 40B, respectively. Further, cleaning rollers 44Y, 44M, 44K, and 44C that collect and temporarily hold untransferred residual toner remaining on the photosensitive drums 14Y, 14M, 14K, and 14C are in contact with each other. Each charging roll is arranged on the upstream side in the rotation direction of each photosensitive drum from the scanning area of each photosensitive drum, and each cleaning roll is arranged on the upstream side in the rotation direction of each photosensitive drum from each charging roll. Has been.

  Further, the first primary intermediate transfer drum 40A, the second primary intermediate transfer drum 40B, and the secondary intermediate transfer drum 40C are not transferred to the sheet P, but are transferred to the first primary intermediate transfer drum 40A and the second primary intermediate transfer drum 40A. Cleaning rollers 46A, 46B, and 46C that remove untransferred residual toner remaining on the intermediate transfer drum 40B and the secondary intermediate transfer drum 40C are in contact with each other.

  Further, as shown in FIG. 3, the transfer roller unit 50 is provided with a transfer roller for transferring the toner image by pressing the paper P against the secondary intermediate transfer drum 40C. The transfer roller 48 has a roll structure in which an elastic layer 48B made of epichlorohydrin rubber or the like is formed on a metal roll core material 48A, and a drive gear 52 is attached to one end portion in the axial direction of the roll core material 48A. The transfer roller 48 is rotated by the driving force transmitted to the driving gear 52.

  At the time of transfer, the transfer roller 48 is applied with a transfer voltage having a polarity opposite to the charging polarity of the toner image from the transfer power supply device (not shown) to the roll core material 48A under constant voltage control. As a result, as shown in FIG. 4, the sheet P fed into the nip N between the secondary intermediate transfer drum 40C and the transfer roller 48 is formed between the secondary intermediate transfer drum 40C and the transfer roller 48. The toner image formed on the secondary intermediate transfer drum 40C is electrostatically transferred by the transfer electric field.

  Further, as shown in FIG. 3, a bearing 54 and a ball bearing 56 are rotatably fitted to both ends of the roll core metal 48A. The bearing 54 is disposed inside the ball bearing 56 and is attached to the unit housing 58 of the transfer roller unit 50. The transfer roller 48 is accommodated in a U-shaped groove 58E (see FIG. 4) of the unit housing 58. . The ball bearing 56 is urged toward the secondary intermediate transfer drum 40C by an urging means (not shown) provided in the apparatus main body, whereby the transfer roller 48 is pressed against the secondary intermediate transfer drum 40C.

  Here, the unit housing 58 is not fixed to the apparatus main body by fixing means such as screws, but is suspended from the apparatus main body by the transfer roller 48. A rotation stop pin 58B is provided on the side surface 58A on the non-drive side of the unit housing 58, and the rotation stop pin 58B is formed in a rotation stop long hole 60 formed in the side plate on the non-drive side of the apparatus body. Has been inserted. Thus, the unit housing 58 is prevented from rotating around the transfer roller 48, and each part of the unit housing 58 is positioned.

  The position of the unit housing 58 includes a pre-transfer guide 60 that guides the leading end of the paper P conveyed to the nip N between the secondary intermediate transfer drum 40C and the transfer roller 48, and after the toner image is transferred. There are a post-transfer guide 62 that guides the leading end of the paper P, a static elimination needle 64 that is discharged from the paper P on which the toner image is transferred, and the like.

  As shown in FIG. 4, the static elimination needle 64 is a stainless steel plate that extends in a direction orthogonal to the conveyance direction of the paper P (hereinafter referred to as the width direction), has an end surface facing the paper P, and has a blade shape. Is disposed so that the tip of the blade shape does not contact the paper P substantially parallel to the axial direction of the transfer roller 48. A recess 58D is formed in the unit housing 58 so as to face the partition wall 58C, and a charge removal needle cover 66 is fitted into the unit housing 58 to hold the charge removal needle 64 inserted in the recess 58D.

  A static elimination voltage having a polarity opposite to the charge applied to the back surface of the paper P by the transfer roller 48 is applied to the static elimination needle 64 from a static elimination power supply device (not shown). As a result, the charge is eliminated so that the charge existing on the back surface of the paper P after passing through the nip portion N is reduced. As a result, the electrostatic attraction force between the paper P and the secondary intermediate transfer drum 40C is reduced, so that the paper P after transfer is easily peeled off from the secondary intermediate transfer body 40C.

  In addition, a neutralizing cloth 68 is bonded to the back surface of the surface of the neutralizing needle cover 66 that presses the neutralizing needle 64. The neutralizing cloth 68 protrudes from the transport path of the paper P toward the secondary intermediate transfer body 40C, and contacts the back surface of the transported paper P to remove charges accumulated on the back surface of the paper P.

  Here, the surface layer of the secondary intermediate transfer drum 40C is formed by coating a resin layer on silicon rubber, and the surface layer has a hardness of 45 ° and a thickness of 5 mm. On the other hand, the elastic layer 48B of the transfer roller 48 has a hardness of 80 ° and a thickness of 2.2 mm, and the hardness is lower than that of the secondary intermediate transfer drum 40C. Therefore, at the nip portion N between the transfer roller 48 and the secondary intermediate transfer drum 40C, the transfer roller 48 bites into the secondary intermediate transfer drum 40C. The amount of biting of the transfer roller 48 into the secondary intermediate transfer drum 40C is 0.5 mm.

  The leading end of the paper P that has passed through the nip N has the habit of traveling toward the roller side having high hardness. In the case of the printer 10, the transfer roller 48 has higher hardness than the secondary intermediate transfer drum 40C. The leading end of the paper P travels toward the transfer roller 48 side.

  Therefore, in the printer 10, the post-transfer guide 62 and the running surface S 1 on the downstream side in the running direction from the nip portion N of the paper P so that the leading end of the paper P does not enter between the partition wall 58 C and the transfer roller 48. The transfer roller 48 is covered with the curved surface S2 by interposing a curved surface S2 facing the traveling surface S1 and an area surrounded by the surface S3 which is in contact with the curved surface S2 and is substantially perpendicular to the traveling surface S1. Crawling up to the transfer drum 40C side.

  As a result, the leading edge of the peeled paper P enters between the post-conveying guide 62 and the transfer roller 48, and the transport jam that the paper P is wrapped around the transfer roller 48 is prevented. Further, it is possible to prevent the leading edge of the paper P from hitting the post-transfer guide 62 and damaging the leading edge of the paper P.

  As shown in FIG. 5, the post-transfer guide 62 has a structure in which a plurality of ribs 62A arranged at a predetermined pitch in the width direction of the paper P are connected by reinforcing portions 62B extending in the width direction of the paper P. It has become. Further, the post-transport guide 62 is formed integrally with the static elimination needle cover 66 and is detachable from the unit housing 58. For this reason, the transfer roller 48 can be inserted into the U-shaped groove 58E from directly above and can be easily attached and detached, so that the assembling property is good and the maintenance property is also high.

  As shown in FIG. 4, the rib 62 </ b> A is formed at an acute angle by a curve L <b> 1 along the curved surface S <b> 1 and a straight line L <b> 2 along the traveling surface S <b> 1 and straddles the static elimination needle 64. For this reason, the rib 62A does not block the discharge between the static elimination needle 64 and the paper P.

  Further, as shown in FIG. 6, the ribs 62 </ b> A are arranged at one pitch with respect to the three teeth of the static elimination needle 64 in accordance with the valley portion 64 </ b> A of the static elimination needle 64. The distance between the upper end of the rib 62A and the apex 64B of the static elimination needle 64 is 2 mm. Here, if the paper P gets too close to the vertex 64B of the static elimination needle 64, the discharge area by the static elimination needle 64 becomes narrow, but the distance between the paper P and the vertex 64B of the static elimination needle 64 becomes 2 mm or less. Therefore, the entire back surface of the paper P can be neutralized uniformly.

  As shown in FIG. 7, the cross section of the rib 62 </ b> A has a stepped shape with a thin upper end that may contact the paper P. For this reason, the contact area between the paper P and the rib 62A can be reduced, and electrostatic scattering of toner due to frictional charging between the rib 62A and the paper P can be reduced.

  Further, the rib 62A is made of polypropylene which is a material that is easily charged to the same polarity as the toner. Therefore, the charge having the opposite polarity to the toner applied to the back surface of the sheet P by the transfer roller 48 is attracted to the charge having the same polarity as the toner frictionally charged on the rib 62A. As a result, the toner on the paper P is attracted to the portion of the paper P that is in contact with the rib 62A. That is, the toner on the paper P does not scatter from the portion of the paper P that is in contact with the rib 62A, and a toner image with white streaks is not formed on the paper P.

  Next, a second embodiment will be described. In addition, the same code | symbol is attached | subjected to the structure same as 1st Embodiment, and description is abbreviate | omitted.

  As shown in FIG. 8A, both ends of the transfer roller 70 are attached to the unit housing 58 by bearings 72. The transfer roller 70 has a smaller outer diameter than the transfer roller 48 of the first embodiment. As described above, since the unit housing 58 is suspended from the transfer roller 48, when the outer diameter of the transfer roller 70 is changed, the positional relationship of each part of the unit housing 58 with respect to the secondary intermediate transfer body 40C. Change.

  When the outer diameter of the transfer roller 70 is reduced and the shape of the bearing 72 and the shape of the unit housing 58 are not changed as in the present embodiment, as shown in FIG. The post-transfer guide 62 approaches the secondary intermediate transfer drum 40C. In particular, the corner portion K facing the nip portion N of the post-transfer guide 62 is located on the secondary intermediate transfer drum 40C side with respect to the progress line L of the paper P after separation illustrated by a chain line. For this reason, the leading end portion of the paper P after peeling enters between the post-transfer guide 62 and the transfer roller 70, and the paper P is wound around the transfer roller 70. Alternatively, the leading edge of the paper P hits the post-transfer guide 82 and the leading edge of the paper P is damaged.

  In order to prevent this, normally, when the outer diameter of the transfer roller 70 is changed, the shape of the unit housing 58 is changed in order to change the mounting position of the bearing 72. For this reason, the mold shape of the unit housing 58 has to be changed, resulting in an increase in cost.

  Therefore, in this embodiment, as shown in FIGS. 8A and 9, the unit housing of the bearing 72 is made eccentric by a predetermined amount Q with respect to the center P1 of the inner diameter of the bearing 72 with respect to the center P2 of the outer diameter. Therefore, it is not necessary to change the position of the unit housing 58 or to change the shape of the post-transfer guide 62, thereby making it unnecessary to change the die shape of the unit housing 58.

  The bearing 72 has an outer diameter, a shape of a rotation stop key 72A that engages with a key groove 58G formed in a bearing mounting portion 58F of the unit housing 58, and a flange 72B that prevents the transfer roller 70 from coming off in the axial direction. The shape and the like are exactly the same as those of the bearing 54 of the first embodiment, and are different from the bearing 54 of the first embodiment in that the thickness of the cylindrical portion 72C fitted to the roll core 70A of the transfer roller 72 is not uniform.

  The center P1 of the inner diameter of the cylindrical portion 72C of the bearing 72 is eccentric by a predetermined amount Q on the opposite side of the rotation stop key 72A in the radial direction with respect to the center P2 of the outer diameter. Since the rotation stop key 72A is disposed on the opposite side of the secondary intermediate transfer drum 40C with the center P2 of the outer diameter therebetween, the unit housing 58 is secondary by a predetermined amount Q from the state of FIG. Move away from the intermediate transfer drum 40C. Thus, the position of the corner portion K of the post-transfer guide 62 is closer to the transfer roller 70 than the travel line L of the paper P after peeling, so that there is no trouble in transporting the paper P.

  Note that the mounting portion referred to in claim 2 corresponds to the outer peripheral surface 72D of the cylindrical portion 72C fitted to the bearing mounting portion 58F of the unit housing 58.

  Next, a modified example of the bearing 72 will be described. In addition, the same code | symbol is attached | subjected to the structure same as 1st, 2nd embodiment, and description is abbreviate | omitted.

  As shown in FIG. 10C, on the outer peripheral surface of the cylindrical portion 74C of the bearing 74 in which the center P1 of the inner diameter is eccentric by a predetermined amount Q with respect to the center of the outer diameter, eight rotations are made at intervals of 45 degrees. A stop key 74A is formed.

  Further, five key grooves 76G for locking the rotation stop key 74A are formed in the bearing mounting portion 76F of the unit housing 76 to which the bearing 74 is mounted. For this reason, as shown in FIG. 10A, when the bearing 74 is mounted on the bearing mounting portion 76F with the thickest portion of the cylindrical portion 74C facing the pre-transfer guide 60, the post-transfer guide 62 is moved to the transfer roller 70. To approach. Also, as shown in FIG. 10B, when the bearing 74 is attached to the bearing attachment portion 76F with the thinnest portion of the cylindrical portion 74C facing the pre-transfer guide 60, the post-transfer guide 62 is moved from the transfer roller 70. Leave.

  As described above, the center P1 of the inner diameter of the bearing 74 is decentered by a predetermined amount Q with respect to the center P2 of the outer diameter, and the direction in which the bearing 74 is attached can be selected in a stepwise manner. The position of each part of the unit housing 76 can be adjusted stepwise.

  As a result, when the outer diameter of the transfer roller 70 is changed or when the process speed is changed and the behavior of the conveyance of the paper P is changed, the shape of the unit housing 76, the post-transfer guide 62, etc. is changed. It can be made unnecessary.

  Even if there are some errors between the finished dimensions of the unit housing 76 and the post-transfer guide 62 and the design values, the errors can be canceled depending on the direction in which the bearing 74 is attached. Therefore, there is a margin for slightly reducing the required degree of dimensional accuracy of the unit housing 76, the post-transfer guide 62, and the like, and the yield of the unit housing 76, the post-transfer guide 62, etc. is increased.

  Next, modified examples of the bearings 72 and 74 will be described.

  As shown in FIG. 11, in the bearing 78, five key grooves 78G are formed at predetermined intervals on the outer peripheral surface of the cylindrical body 78C, and the key groove 78G is locked to the bearing mounting portion 80F of the unit housing 80. One rotation stop key 80A is formed. As a result, the mounting direction can be adjusted stepwise as with the bearing 74 described above.

  As shown in FIG. 12, the bearing 82 is provided with a flange 82B at one end of the cylindrical body 82C in the axial direction. The flange 82B has one or a plurality of protrusions protruding from the bearing mounting portion of the unit housing. Eight anti-rotation locking holes 82G into which anti-rotation pins are fitted are formed at intervals of 45 °. Thereby, the mounting direction of the bearing 82 can be adjusted stepwise.

  As shown in FIG. 13, a U-shaped anti-rotation locking hole 84 </ b> G that engages with an anti-rotation protrusion formed on the bearing mounting portion of the unit housing is provided at a flange portion 84 </ b> B of the bearing 84 at an interval of 45 °. 8 and the mounting direction of the bearing 84 can be adjusted stepwise.

  In the first and second embodiments, the outer shape of the bearing serving as the bearing mounting portion mounted on the bearing mounting portion is circular. However, as illustrated in FIG. 14A, the mounting portion 86D of the bearing 86, that is, The outer shape may be rectangular. In this case, the center P2 of the attachment portion 86D is an intersection of the two diagonal lines L.

  As shown in FIG. 14B, the mounting portion 88D of the bearing 88, that is, the outer shape may be a polygon such as a hexagon. In this case, the center P2 of the attachment portion 88D is an intersection of the three diagonal lines L.

  Further, the bearing of the present invention has been described by taking the transfer roller of the printer as an example, but the bearing of the present invention is not limited to this, and in the printer, the roller and the peripheral components of the roller such as a fixing roller and thermistor are used. The present invention can be applied to a unit in which the positional relationship is important, and can be applied to various devices in which the positional relationship between rollers and peripheral components of the roller is important in addition to a printer.

1 is a diagram illustrating an outline of a printer according to a first embodiment. 1 is a diagram schematically illustrating a print head device of a printer according to a first embodiment. It is a perspective view which shows the transfer roller unit of the printer of 1st Embodiment. It is sectional drawing which shows the transfer roller unit of the printer of 1st Embodiment. It is a perspective view which shows the static elimination needle cover of the printer of 1st Embodiment. It is sectional drawing which shows the static elimination needle and post-transfer guide of the printer of 1st Embodiment. It is sectional drawing of the after-transfer guide of the printer of 1st Embodiment. (A) It is sectional drawing which shows the transfer roller unit of the printer of 2nd Embodiment. (B) It is sectional drawing which shows the transfer roller unit of the printer of 2nd Embodiment. It is a perspective view which shows the bearing of the printer of 2nd Embodiment. (A) It is a figure which shows the modification of the bearing of the printer of 1st, 2nd embodiment. (B) It is a figure which shows the modification of the bearing of the printer of 1st, 2nd embodiment. (C) It is a figure which shows the modification of the bearing of the printer of 1st, 2nd embodiment. It is a figure which shows the modification of the bearing of the printer of 1st, 2nd embodiment. It is a figure which shows the modification of the bearing of the printer of 1st, 2nd embodiment. It is a figure which shows the modification of the bearing of the printer of 1st, 2nd embodiment. (A) It is a figure which shows the modification of the bearing of the printer of 1st, 2nd embodiment. (B) It is not shown the modification of the bearing of the printer of 1st, 2nd embodiment.

Explanation of symbols

10 Printer (image forming device)
40C secondary intermediate transfer drum (first rotation functional member, image carrier)
58 Unit housing (mounting member)
58G rotation stop keyway (engaged part, engaged part)
62 Post-transfer guide (guide means)
70 Transfer roller (shaft, second rotating functional member)
72 Bearing 72A Keyway (engaged part, engaged part)
74 Bearing 74A Keyway (engaged part, engaged part)
74D Mounting part 76 Unit housing (Mounting member)
76G rotation stop keyway (engaged part, engaged part)
78 Bearing 78G Non-rotating keyway (engaged part, engaged part)
80 Unit housing (mounting member)
80A rotation stop projection (engagement part, engaged part)
82 Bearing 82G Anti-rotation locking hole (engagement part, engaged part)
84 Bearing 84G Anti-rotation locking hole (engagement part, engaged part)
86 Bearing 86D Mounting part 88 Bearing 88D Mounting part N Nip part P Paper (image forming medium)
P1 Center of inner diameter P2 Center of outer diameter Q Predetermined amount

Claims (7)

A bearing that rotatably supports a shaft,
A bearing characterized in that the center of the inner diameter is eccentric by a predetermined amount with respect to the center of the outer diameter. A bearing that rotatably supports a shaft,
A bearing characterized in that the center of the inner diameter is eccentric by a predetermined amount with respect to the center of the mounting portion. A bearing mounting structure comprising a bearing that rotatably supports a shaft, and a mounting member to which the bearing is mounted,
In the bearing, the center of the inner diameter is eccentric by a predetermined amount with respect to the center of the outer diameter,
At least one of an engaging portion formed on the bearing or the mounting member and an engaged portion formed on the mounting member or the bearing and engaging with the engaging portion is provided in the circumferential direction of the shaft. A bearing mounting structure characterized by that. A first rotation function member;
A second rotating functional member that nips and conveys the first rotating functional member and the image forming medium;
A bearing rotatably supporting the second rotational function member, wherein the center of the inner diameter is eccentric by a predetermined amount with respect to the center of the outer diameter;
A mounting member to which the bearing is mounted;
An image forming apparatus comprising:   At least one of an engaging portion formed on the bearing or the mounting member and an engaged portion formed on the mounting member or the bearing and engaged with the engaging portion is a circumferential direction of the second rotation function member. The image forming apparatus according to claim 4, wherein a plurality of the image forming apparatuses are provided. The second rotation functional member is a transfer roller that presses the image forming medium against an image carrier as the first rotation functional member and transfers an image formed on the image carrier to the image forming medium;
Guide means for guiding the conveyance of the image forming medium after the image is transferred is provided on the mounting member,
6. The image forming apparatus according to claim 4, wherein a positional relationship between a nip portion between the transfer roller and the image carrier and the guide unit is adjusted by changing an eccentric amount of the bearing.   The positional relationship between the guide unit and the nip portion between the transfer roller and the image carrier is adjusted by changing the circumferential mounting position of the second rotation function member of the bearing with respect to the mounting member. The image forming apparatus according to claim 5 or 6.

Images