JP2013003379A - Drive transmission device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit vibration between an inclined fixed shaft and a frame body fixing the fixed shaft.SOLUTION: In a drive transmission device, a fixed shaft 102 fixed to a first frame body 103 and rotatably supporting a first gear 101 is inclined with respect to a rotary shaft X of a second gear 100, in which the fixed shaft 102 is fitted to the second frame body 105 through a vibration suppression member 104.

Description

  The present invention relates to a drive transmission device that transmits a driving force from a drive source such as a motor, and an image forming apparatus such as a copier, a facsimile machine, a printer, or a multi-function machine including the drive transmission device.

  When the helical gear is used in the gear train of the drive transmission device, the helical gear is easily deformed by receiving a thrust force from the driving load. When the helical gear is tilted by such deformation, it is difficult to ensure proper meshing with other gears, and vibration may occur at the meshing portion between the helical gears and the other gears. As a result, pitch unevenness for each tooth due to vibration at the gear meshing portion is transmitted to the gear train. In particular, pitch irregularities in the gear train that drives the photosensitive drum of the image forming apparatus may cause rotational irregularities in the photosensitive drum, which may hinder further image quality improvement.

  Therefore, even if the meshing portion of the gear driving the photosensitive drum and the upstream gear is deformed, the shaft of the upstream gear is set with respect to the helical gear shaft driving the photosensitive drum so that proper meshing can be ensured. The structure which inclines is proposed (refer patent document 1).

JP2007-212557

  6A and 6B are cross-sectional views showing such a conventional drive transmission device, where FIG. 6A is a schematic view of the whole, and FIG. 6B is an enlarged view of a portion U in FIG. The driving force from the motor 607 is transmitted to the gear 600, which is a helical gear, via the gear 606 and the gear 601, and the shaft (fixed shaft) of the gear 601 is secured so as to ensure normal meshing with the gear 600. 602 is tilted. For this reason, the meshing portion K1 between the gear 601 and the gear 600 meshes correctly.

  However, it is difficult to ensure proper meshing with the meshing portion K2 with the gear 606, and vibration easily occurs at the meshing portion K2.

  Here, when one end of the inclined shaft 602 is fixed to the apparatus side plate 608 by caulking or the like, the end of the shaft 602 that is not caulked is fitted to the other side plate 605 in order to determine the inclination of the shaft 602. As shown in FIG. 6B, the shaft 602 is fitted obliquely with respect to the opening of the side plate 605, and the contact area between the shaft 602 and the opening is reduced. Therefore, the inclined shaft 602 is inclined. The contact pressure at the contact points P1 and P2 with the opening increases. Therefore, the vibration generated at the meshing portion K2 and the vibration of the drive source 607 itself are easily transmitted to the other side plate 605 through the shaft 602. When vibration is transmitted to the side plate 605, the vibration is transmitted to the image forming means supported by the side plate 605, which may cause image defects.

  In view of the above problems, the present invention provides a frame that fits between a fixed shaft and a fixed shaft in a drive transmission device in which a fixed shaft that rotatably supports a gear is inclined with respect to the rotation shaft of another gear. It is an object of the present invention to provide a drive transmission device that suppresses transmission of vibration between the image forming apparatus and an image forming apparatus including the drive transmission device.

  According to the present invention, a first gear that rotates by driving from a drive source, a second gear that meshes and rotates with the first gear, a fixed shaft that rotatably supports the first gear, and the fixed shaft are fixed. A first frame body, and a second frame body disposed opposite to the first frame body with the first gear interposed therebetween, wherein the fixed shaft is relative to the rotation shaft of the second gear. In the drive transmission device provided to be inclined, the fixed shaft is fitted into the second frame body via a vibration suppressing member.

  According to the present invention, in the drive transmission device in which the fixed shaft that rotatably supports the gear is inclined with respect to the rotation shaft of the other gear, between the fixed shaft and the frame that fits the fixed shaft. The transmission of vibration can be suppressed.

(A) Sectional drawing of a drive transmission device. (B) The enlarged view of the meshing part K1 vicinity of Fig.1 (a). The figure which shows the transmission path | route of a vibration typically. 1 is a schematic sectional view of an image forming apparatus. (A) Sectional drawing of a drive transmission device. (B) The figure which looked at a part of Drawing 4 (a) from the C direction. (A) Sectional drawing of a drive transmission device. (B) The figure which looked at a part from D direction. (A) Whole sectional drawing of the conventional drive transmission device. (B) FIG. 6 (a) is a cross-sectional view of the U portion.

<First Embodiment>
The drive transmission device of this embodiment is mounted on an image forming apparatus. First, the overall configuration of the image forming apparatus including the drive transmission device of the present invention will be described.

(Image forming device)
FIG. 3 is a schematic sectional view of the image forming apparatus. The image forming apparatus 300 is an electrophotographic image forming apparatus, and includes a photosensitive drum 110 that is a drum-shaped photosensitive member. The photosensitive drum 110 is charged by a charging unit (not shown) and then exposed to a laser beam 301 corresponding to image information by a laser scanner 301 including a laser diode, a polygon mirror, a lens, and a reflection mirror (not shown). As a result, an electrostatic latent image corresponding to the image information is formed on the photosensitive drum 110. This latent image is developed by developing means provided inside the process cartridge 302 that supports the photosensitive drum 110, and a toner image is formed on the photosensitive drum 110.

  On the other hand, a sheet (recording material) S onto which a toner image is transferred later is fed by a sheet feeding device 305 from a feeding cassette 303 arranged below the image forming apparatus 300 and is fed into the main body of the apparatus by a pair of conveying rollers 306. Be transported. Next, the sheet S is conveyed to a transfer nip portion formed by the photosensitive drum 110 and a transfer roller 304 as a transfer unit in synchronization with the toner image formed on the photosensitive drum 110. In the transfer nip portion, the toner image on the photosensitive drum 110 is transferred onto the paper S by the voltage applied to the transfer roller 304.

  Thereafter, the sheet S to which the toner image has been transferred is sent to the fixing unit 310, and a fixing process for fixing the transferred toner image on the sheet surface is performed. The fixing unit 310 includes a driving roller 311 and a fixing roller 312 incorporating a heater, and applies heat and pressure to the passing paper S to fix the toner image on the paper S. The sheet S after the fixing process is discharged onto a discharge tray 315 outside the apparatus by an inner discharge roller pair 313 and an outer discharge roller 314.

  In the double-sided printing mode (the mode in which images are formed on both the front and back sides of the paper S), the inner discharge roller pair 313 or the switchback roller pair 316 is temporarily placed on the intermediate tray 318 via the duplex conveyance path 317. Loaded and stored. Then, the sheet S is conveyed again from the intermediate tray 318 to the transfer nip by the refeed device 319, and thereafter discharged to the discharge tray 315 outside the apparatus through the same process as described above.

  The toner on the photosensitive drum 110 after passing through the transfer nip is cleaned by a cleaning unit (not shown).

  The photosensitive drum 110, charging unit, laser scanner 301, developing unit, transfer roller 304, and fixing unit 310 as described above are image forming units.

(Drive transmission device)
Next, the drive transmission device will be described. FIG. 1A is a cross-sectional view of the drive transmission device. FIG. 1B is an enlarged view of the vicinity of the meshing portion K1 in FIG. The drive transmission device of the present embodiment is mounted on the image forming apparatus as a drive transmission unit that transmits a driving force to the process cartridge 302 (FIG. 3) detachably mounted on the image forming apparatus 300 (FIG. 3).

  At a longitudinal end of the photosensitive drum 110 attached to the process cartridge 302 (not shown), a convex portion 111a as a shaft coupling is provided on a drum flange 111 fixed to the photosensitive drum 110. On the image forming apparatus main body side, when the process cartridge 302 is mounted on the main body, a concave portion 100a is provided as a shaft joint coaxial with the rotation shaft of the photosensitive drum 110. The concave portion 100 a is provided so as to protrude from the side surface of the large gear 100 that rotates coaxially with the large gear 100 as the first gear and transmits the driving force of the motor 107 as a driving source to the photosensitive drum 110. The convex portion 111a and the concave portion 100a are coupling means for transmitting driving force from the apparatus main body side to the photosensitive drum 110 by being coupled (engaged) with each other.

  A driving force is transmitted from the motor 107 to the large gear 100 downstream in the drive transmission direction by a gear train including the large gear (second gear) 100, the small gear (first gear) 101, and the small gear 106. The small gear 101, the small gear 106, and the motor 107 are respectively supported by a first frame 103 serving as a side plate (frame) of the drive unit. The large gear 100 is rotatably supported by a second frame 105 as a casing (frame) of the image forming apparatus main body. The first frame body and the second frame body are plate-shaped metal members (sheet metal), and are arranged to face each other, and between the first frame body 103 and the second frame body 105, the large gear 100, the small gear 101, and the small frame body. A gear 106 is arranged. That is, the second frame 105 is disposed to face the first frame 103 with the large gear 100, the small gear 101, and the small gear 106 interposed therebetween.

  The large gear 100 is a helical gear and meshes with the helical gear 101 on the upstream side in the drive transmission direction. The helical gear of the large gear 100 is a tooth having a twist direction and an inclination angle that generates a thrust force that moves the concave portion 100a toward the convex portion 110a when the driving force is transmitted from the small gear 101. . Accordingly, when the motor 107 is driven during image formation, the concave portion 100a is moved and engaged in a direction toward the convex portion 110a by thrust. The small gear 101 is rotatably supported by a fixed shaft 102 having one axial end fixed to the first frame. The fixed shaft 102 is fixed to the first frame 103 by caulking from the viewpoint of positional accuracy and assembly of the drive transmission mechanism. A vibration suppression member 104 made of resin (synthetic resin) is fitted to the other axial end of the fixed shaft 102, and the outer peripheral surface of the vibration suppression member 104 is fitted into the fitting hole 105 a of the second frame body 105. It is mated. That is, the other axial end of the fixed shaft 102 is supported by the second frame body 105 via the vibration suppressing member 104.

  A thrust force F, which is a force in the thrust direction (rotational axis direction), is applied to the large gear 100 by a driving load. The thrust force F causes a deformation δ in the thrust direction in the vicinity of the meshing portion with the small gear 101. Thus, proper meshing is not ensured between the deformed helical gears, and vibration for each tooth tends to occur. Therefore, the fixed shaft 102 that rotatably supports the small gear 101 is inclined toward the shaft side of the large gear 100 in the thrust direction with respect to the rotational shaft of the large gear 100. That is, even if the large gear 100 is deformed, the small gear 101 is inclined by the angle θ with respect to the rotation axis X of the large gear 100 so that the large gear 100 and the small gear 101 are correctly meshed with each other.

  In order to incline the fixed shaft 102 by the angle θ in this way, the center of the fitting hole 105a of the second frame 105 is formed at a position shifted by α with respect to the center of the fixed portion 102a of the fixed shaft 102. That is, the inclination of the fixed shaft 102 is determined by the positional relationship between the fixed portion 102a and the fitting hole 105a.

  Here, since the fixed shaft 102 is caulked and fixed to the first frame 103, vibration from the motor 107 is easily transmitted from the first frame 103 to the fixed shaft 102. Further, since the fixed shaft 102 is also fixed to the second frame body 105, vibration is transmitted from the fixed shaft 102 to the second frame body 105. FIG. 2 schematically shows such a vibration transmission path. The transmission path of vibration can be classified mainly as follows. The first is a path V1 through which the vibration for each tooth generated in the meshing portion K2 of the small gear 101 and the small gear 106 due to the inclination of the fixed shaft 102 is transmitted to the second frame 105 through the gear train. Is a path V2 in which the vibration for each tooth generated at the meshing portion K2 of the small gear 101 and the small gear 106 is transmitted from the fixed shaft 102 to the second frame 105. Third, the vibration of the motor 107 is the first frame. A path V <b> 3 is transmitted from the body 103 to the second frame 105 from the fixed shaft 102.

  By the way, since the second frame 105 supports the photosensitive drum 110 and other image forming means directly or indirectly, when the second frame 105 vibrates, the vibration is transmitted to the image forming means. As a result, an image to be formed is disturbed, and an image defect may occur.

  Therefore, in order not to generate vibration for each tooth generated at the meshing portion K2 of the small gear 101 and the small gear 106, all the upstream of the tilted small gear 101 on the upstream side in the drive transmission direction so as to properly mesh with the meshing portion K2. It is conceivable to incline the rotation axis of the gear in an appropriate direction.

  However, if an attempt is made to incline the rotating shaft that is fixed to the first frame 103 only at one end, it is difficult to hold the gear in an inclined state because of strength or the like. Further, when the rotation shaft is configured to be fitted to the second frame 105 on the other end side, the angle at which each of the plurality of rotation shafts is inclined is different (the phases of the rotation shafts are different). The assemblability at the time of fitting with the rotating shaft fitting portion of the body 105 is deteriorated.

  In addition, it is conceivable that the mounting seat surface itself of the rotating shaft is formed obliquely in accordance with the inclination of each rotating shaft, but the processing becomes complicated.

  For this reason, vibrations are applied to the image forming means and the like by tilting the rotation shafts of all gears upstream of the tilted small gear 101 in an appropriate direction and properly meshing with the meshing portion K2. It is difficult to suppress the transmission. Therefore, in this embodiment, in order to reduce the vibration transmitted to the fixed shaft 102 among these vibration transmission paths, the fitting with the second frame body 105 at the tip of the fixed shaft 102 is suppressed with the vibration of the synthetic resin. This is done via the member 104. That is, the vibration suppressing member 104 made of a material different from that of the fixed shaft 102 is fitted between the fixed shaft 102 and the fitting hole 105 a of the second frame 105, so that the fixed shaft 102 is moved to the second frame 105. Direct transmission of vibration is suppressed.

  In the present embodiment, the fixed shaft 102 is caulked to the first frame 103 on the drive unit side. However, it may be fixed by caulking to the second frame 105 on the image forming apparatus 300 main body side, and the fixing shaft 102 and the fitting hole of the first frame 103 may be fixed via the vibration suppressing member 104. Further, although the fixed shaft 102 is fixed by caulking, the shaft may be fixed with a screw or the like.

  Also, the assembly is performed by combining the second frame 105 (image forming apparatus main body side) that supports the large gear 100 with the second frame (drive unit side) that supports the small gears 101 and 106 and the motor 107. Done. At this time, the vibration suppressing member 104 may be fitted to the second frame 105 after being fitted to the fixed shaft 102 in advance, or may be fixed to the second frame 105 to which the vibration suppressing member 104 is fitted beforehand. The shaft may be fitted. Moreover, although the synthetic resin is used for the vibration suppressing member 104, the material is not limited to this, and the material is different from that of the fixed shaft 102, and the shaft position can be held with the shaft tilted, and the material can be elastically deformed. If it is.

  In this embodiment, the drive transmission device is mounted on the image forming apparatus as a drive unit. However, the drive transmission device may be mounted on another device as a drive unit.

  As described above, the shaft that rotatably supports the gear is fitted to the first frame and the second frame, so that the shaft is inclined with respect to the rotation shaft of the other gear. In this case, the transmission of vibration between the shaft and the second frame body can be suppressed by fitting the shaft to the second frame body via the vibration suppressing member.

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

  4A is a cross-sectional view of the drive transmission device, and FIG. 4B is a view of a part of FIG. 4A viewed from the C direction.

  In the present embodiment, one end of the fixed shaft 402 that supports the small gear 101 is fixed by caulking to the side plate 103 of the drive unit that is the second frame. The vibration suppression member 404 is fitted to the other end of the fixed shaft 402 that supports the small gear, and the outer peripheral surface of the vibration suppression member is fitted to the support portion 105 a provided in the second frame 105.

The center of the fixed portion 402a of the fixed shaft 402 crimped to the side plate 103 of the drive unit and the position of the hole center of the support portion 105a provided in the housing 105 are at the same position. The shaft center of the fixed shaft 402 and the shaft center of the vibration suppressing member 404 are formed at a position shifted by β. In this way, by shifting the phases of the small gear fixed shaft 402 and the vibration suppressing member 404, the small gear fixed shaft 402 is tilted toward the large gear 100 in the thrust direction with respect to the large gear 100 axis. Yes. As a result, even if the small gear is inclined by the angle θ shown in FIG. 4A and the large gear 100 is deformed, the meshing of the gear can be kept normal. Further, the vibration transmitted to the image forming unit through the small gear shaft 102 is reduced by fitting the vibration suppressing member 404 between the fixed shaft 402 and the support portion 105a of the housing.
In this embodiment, since the center of the outer shape of the vibration suppressing member 404 and the center of the shaft mounting hole are different, a phase shift occurs between the fixed shaft 402 of the small gear and the vibration suppressing member 404. Therefore, in order to match the phases of the small gear fixed shaft 402 and the vibration suppressing member 404, the tip 402b of the small gear shaft is D-shaped for phase matching. In this embodiment, as shown in FIG. 4B, the tip shape of the fixed shaft 402 is D-shaped, but this is not restrictive, and the phase of the fixed shaft 402 and the vibration suppressing member 404 is determined. Any shape is acceptable.

  Next, another embodiment of the present embodiment will be shown. FIG. 5A is a cross-sectional view of the drive transmission device, and FIG. 5B is a view of a part of FIG. 5A viewed from the D direction. A configuration in which the position of the portion of the shaft 502 that engages with the vibration suppression member 504 is shifted by γ with respect to the center of the shaft may be assembled without phase matching between the shaft 502 and the vibration suppression member 504. In addition, as the configuration in which the shaft of the small gear 101 is inclined, the positional relationship between the fixed shaft 102 crimped to the first frame 103 and the fitting portion of the second frame 105 is fixed as in the first embodiment. The configuration in which the center of the fitting hole of the second frame body is shifted by α with respect to the shaft center of the shaft 102, and the shaft center of the fixed shaft of the small gear 101 and the vibration suppressing member of this embodiment is β Or you may combine the structure which shifts (gamma).

  As described above, in the present embodiment, as in the first embodiment, the shaft that rotatably supports the gear is fitted to the first frame body and the second frame body, so that the shaft becomes the rotation shaft of the other gear. In the drive transmission device that is inclined with respect to the shaft, the transmission of vibration between the shaft and the second frame body can be suppressed by fitting the shaft to the second frame body via the vibration suppressing member. it can.

100 Large gear 101 Small gear 102 Fixed shaft 103 Drive unit side plate (second frame)
104, 404, 504 Vibration suppression member 105 Case of the image forming apparatus main body (first frame)
107 Motor 110 Photosensitive drum 300 Image forming apparatus K1, K2 Engagement portion α, β, γ Shift amount θ Inclination amount δ Deformation amount

Claims (6)

A first gear that is rotated by driving from a driving source;
A second gear rotating in mesh with the first gear;
A fixed shaft that rotatably supports the first gear;
A first frame to which a fixed shaft of the first gear is fixed;
A second frame disposed opposite to the first frame with the gear interposed therebetween;
In the drive transmission device provided with the fixed shaft inclined with respect to the rotation shaft of the second gear,
The drive transmission device, wherein the fixed shaft is fitted to the second frame body via a vibration suppressing member.   The drive transmission device according to claim 1, wherein the fixed shaft is fixed by caulking to the first frame body.   The drive transmission device according to claim 1, wherein the second gear is a helical gear.   The drive transmission device according to any one of claims 1 to 3, wherein the drive source is fixed to the first frame.   The drive transmission device according to any one of claims 1 to 4, wherein the vibration suppressing member is formed of a resin. The drive transmission device according to any one of claims 1 to 5,
A photoconductor rotated by the drive transmission device;
And an image forming apparatus that forms an image by transferring a toner image formed on the photoreceptor to a recording material.

Images