JP2016169784A - Driving device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a driving device and an image forming device that can reduce the noise of the devices.SOLUTION: A driving device 110 comprises: a driving motor 111; an internal gear such as a speed reduction member 116 that engages with a motor gear 111a of the driving motor 111; a supporting shaft 117 that supports the internal gear; and a holding member such as a first face plate 112 that holds the supporting shaft 117. The driving device 110 comprises a motor holding face plate 114, and the driving motor 111 is positioned at the motor holding face plate 114, which is a member different from the holding member, by fitting a positioning part 111b of the driving motor 111 into a positioning hole part 114a of the motor holding face plate 114.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a drive device and an image forming apparatus.

  In an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a complex machine thereof, many driving units are provided for an image forming operation, and are used for operations of a photoconductor and a transfer belt.

  Patent Document 1 includes a first plate-like frame and a second plate-like frame facing the first plate-like frame, and the internal gear can freely rotate between the first plate-like frame and the second plate-like frame. A driving device holding a supporting shaft is described. In this drive device, the drive motor is attached to the surface of the first plate frame that is the holding member, on the surface opposite to the surface facing the second plate frame. The motor shaft of the drive motor passes through the first casing, and the motor gear provided on the motor shaft meshes with the internal gear.

  In recent years, it has been desired to further reduce the noise of the apparatus. By reducing the diameter of the internal gear, the meshing ratio with the motor gear can be improved and vibration and noise can be suppressed. Therefore, a reduction in the diameter of the internal gear is required to reduce the noise of the device. . However, in the drive device described in Patent Document 1 in which the drive motor is held by the first plate-like frame that is the holding member that holds the support shaft of the internal gear, the internal gear is reduced in diameter for the following reason. It was not fully realized. That is, when the diameter of the internal gear is reduced, the support shaft of the internal gear needs to be disposed at a position close to the motor shaft. Usually, the drive motor is provided with a positioning portion having a diameter larger than that of the motor shaft on the same axis as the motor shaft. The positioning portion is fitted into a positioning hole formed in the first plate-like frame to Positioning. As a result, when the support shaft is arranged at a position close to the motor shaft, the positioning hole cannot form a portion for holding the support shaft in the first plate-like frame as the holding member. Therefore, there has been a problem that the support shaft cannot be disposed at a position sufficiently close to the motor shaft, the diameter of the internal gear cannot be sufficiently reduced, and sufficient noise reduction of the device cannot be realized.

  In order to solve the above problems, the present invention includes a drive motor, an internal gear that meshes with a motor gear of the drive motor, a support shaft that supports the internal gear, and a holding member that holds the support shaft. In the drive device, the drive motor is positioned on a member different from the holding member.

  According to the present invention, the noise of the apparatus can be reduced.

1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of a process unit in the printer. The schematic sectional drawing of a drive device. The schematic perspective view of a drive motor. The schematic sectional drawing which shows the 1st modification of a drive device. The schematic sectional drawing which shows the 2nd modification of a drive device. The principal part perspective view of the 2nd modification of a drive device. The schematic sectional drawing which shows the 3rd modification of a drive device.

An embodiment of an electrophotographic printer (hereinafter simply referred to as “printer 100”) will be described below as an image forming apparatus to which the present invention is applied.
First, a basic configuration of the printer 100 according to the present embodiment will be described.
FIG. 1 is a schematic configuration diagram illustrating the printer 100. The printer 100 includes four process units 26 for forming toner images of black, cyan, magenta, and yellow (hereinafter referred to as K, C, M, and Y). (K, C, M, Y). These use different colors of K, C, M, and Y toners as image forming substances, but otherwise have the same configuration and are replaced when the lifetime is reached.

FIG. 2 is an enlarged explanatory view of one of the four process units 26. Since the four process units 26 are the same except that the colors of the toners used are different, the subscripts (K, C, M, Y) indicating the colors of the toners used are omitted in FIG.
As shown in FIG. 2, the process unit 26 includes a drum-shaped photosensitive member 24 as a latent image carrier, a photosensitive member cleaning device 83, a static eliminator and a charging device 25, and a developing unit 23. It has. The process unit 26 as an image forming unit can be attached to and detached from the main body of the printer 100 so that consumable parts can be replaced at a time.

  The charging device 25 uniformly charges the surface of the photoreceptor 24 that is driven to rotate clockwise in the drawing by the driving unit. The uniformly charged surface of the photoconductor 24 is exposed and scanned by a laser beam L irradiated by an optical writing unit 27 described later, and carries an electrostatic latent image for each color. This electrostatic latent image is developed into a toner image by the developing unit 23 using toner. Then, primary transfer is performed on the intermediate transfer belt 22.

  The photoconductor cleaning device 83 removes transfer residual toner adhering to the surface of the photoconductor 24 after the primary transfer process. Further, the static eliminator neutralizes residual charges on the photoreceptor 24 after cleaning. By this charge removal, the surface of the photoconductor 24 is initialized and prepared for the next image formation.

  The developing unit 23 includes a vertically long hopper portion 86 that stores toner as a developer, and a developing portion 87. An agitator 88 that is rotated by driving means, a toner supply roller 80 as a developer supplying member that is rotated and driven by driving means below the vertical direction, and the like are disposed in a hopper 86 serving as a developer containing portion. Has been. The toner in the hopper 86 moves toward the toner supply roller 80 by its own weight while being agitated by the rotational drive of the agitator 88. The toner supply roller 80 has a metal cored bar and a roller part made of foamed resin or the like coated on the surface of the metal core. The toner accumulated on the lower side of the hopper 86 is applied to the surface of the roller part. Rotate while adhering.

  In the developing unit 87 of the developing unit 23, a developing roller 81 that rotates while contacting the photoreceptor 24 and the toner supply roller 80, a thinning blade 82 that contacts the tip of the developing roller 81, and the like are disposed. Yes. The toner attached to the toner supply roller 80 in the hopper 86 is supplied to the surface of the development roller 81 at a contact portion between the development roller 81 and the toner supply roller 80. When the supplied toner passes through the contact position between the developing roller 81 and the thinning blade 82 as the developing roller 81 rotates, the layer thickness on the surface of the developing roller 81 is regulated. Then, the toner after the regulation of the layer thickness adheres to the electrostatic latent image on the surface of the photosensitive member 24 in the developing region which is a contact portion between the developing roller 81 and the photosensitive member 24. By this adhesion, the electrostatic latent image is developed into a toner image.

  Such a toner image is formed in each process unit 26, and a toner image of each color is formed on each photoconductor 24 of each process unit 26.

  As shown in FIG. 1, an optical writing unit 27 is disposed above the four process units 26 in the vertical direction. The optical writing unit 27 as a latent image writing device optically scans the respective photosensitive members 24 in the four process units 26 with the laser light L emitted from the laser diode based on the image information. By this optical scanning, an electrostatic latent image for each color is formed on the photoreceptor 24. In such a configuration, the optical writing unit 27 and the four process units 26 create K, C, M, and Y toner images as visible images of different colors on the four photosensitive members 24, respectively. It functions as an image means.

  The optical writing unit 27 irradiates the photoconductor 24 through a plurality of optical lenses and mirrors while polarizing the laser light L emitted from the light source by a polygon mirror rotated by a polygon motor in the main scanning direction. . As the optical writing unit 27, an optical writing unit that performs optical writing with LED light emitted from a plurality of LEDs of the LED array may be employed.

  Below the four process units 26, a transfer unit 75 is disposed as a belt device that moves the endless intermediate transfer belt 22 endlessly in the counterclockwise direction while stretching. In addition to the intermediate transfer belt 22, the transfer unit 75 includes a driving roller 76, a tension roller 20, four primary transfer rollers 74 (K, C, M, Y), a secondary transfer roller 21, a belt cleaning device 71, a cleaning backup. A roller 72 and the like are provided.

  The intermediate transfer belt 22, which is a belt member and a transfer belt, includes a driving roller 76, a tension roller 20, a cleaning backup roller 72, and four primary transfer rollers 74 (K, C, M, Y) disposed inside the loop. ). Then, it is moved endlessly in the same direction by the rotational force of the driving roller 76 that is driven to rotate counterclockwise in the drawing by the driving means.

  The four primary transfer rollers 74 (K, C, M, Y) sandwich the intermediate transfer belt 22 that is moved endlessly in this manner between the photoreceptors 24 (K, C, M, Y). As a result of this sandwiching, four primary transfer nips for K, C, M, and Y where the front surface of the intermediate transfer belt 22 and the photoreceptor 24 (K, C, M, Y) are in contact are formed. Yes.

  A primary transfer bias is applied to the primary transfer roller 74 (K, C, M, Y) by a transfer bias power source, whereby the electrostatic latent image on the photosensitive member 24 (K, C, M, Y). Then, a transfer electric field is formed between the primary transfer roller 74 (K, C, M, Y). Instead of the primary transfer roller 74, a transfer charger or a transfer brush may be employed.

  The Y toner formed on the surface of the yellow photoconductor 24Y of the yellow process unit 26Y enters the above-described primary transfer nip for Y as the yellow photoconductor 24Y rotates. In the primary transfer nip for Y, Y toner is primarily transferred from the yellow photoreceptor 24Y to the intermediate transfer belt 22 by the action of the transfer electric field and nip pressure. When the intermediate transfer belt 22 onto which the Y toner image is primarily transferred in this way passes through the primary transfer nip for M, C, K along with its endless movement, the photoreceptor 24 (M, C, K). The upper M, C, and K toner images are superimposed and sequentially transferred onto the Y toner image. A four-color toner image is formed on the intermediate transfer belt 22 by the primary transfer of the superposition.

  The secondary transfer roller 21 of the transfer unit 75 is disposed outside the loop of the intermediate transfer belt 22 and sandwiches the intermediate transfer belt 22 between the tension roller 20 inside the loop. By this sandwiching, a secondary transfer nip where the front surface of the intermediate transfer belt 22 and the secondary transfer roller 21 abut is formed. A secondary transfer bias is applied to the secondary transfer roller 21 by a transfer bias power source. By this application, a secondary transfer electric field is formed between the secondary transfer roller 21 and the tension roller 20 connected to the ground.

  Below the transfer unit 75 in the vertical direction, a paper feed cassette 41 that accommodates a plurality of recording papers stacked in a bundle is slidably attached to the housing of the printer 100. In the paper feed cassette 41, a paper feed roller 42 is brought into contact with the top recording paper in a bundle of paper, and the recording paper is rotated counterclockwise in the figure at a predetermined timing. Send it out toward the paper feed path.

  Near the end of the paper feed path, a registration roller pair 43 composed of two registration rollers is disposed. The registration roller pair 43 stops the rotation of both rollers as soon as a recording sheet serving as a recording member fed from the sheet feeding cassette 41 is sandwiched between the rollers. Then, rotation driving is restarted at a timing at which the sandwiched recording paper can be synchronized with the four-color toner image on the intermediate transfer belt 22 in the above-described secondary transfer nip, and the recording paper is sent out toward the secondary transfer nip.

  The four-color toner image on the intermediate transfer belt 22 that is in close contact with the recording paper at the secondary transfer nip is secondarily transferred onto the recording paper under the influence of the secondary transfer electric field and nip pressure, and combined with the white color of the recording paper. A full color toner image is obtained. The recording paper having the full-color toner image formed on the surface in this way is separated from the secondary transfer roller 21 and the intermediate transfer belt 22 by the curvature when passing through the secondary transfer nip. Then, the toner is sent to a fixing device 40 as a fixing unit via a post-transfer conveyance path.

  Untransferred toner that has not been transferred to the recording paper adheres to the intermediate transfer belt 22 after passing through the secondary transfer nip. This is cleaned from the belt surface by a belt cleaning device 71 in contact with the front surface of the intermediate transfer belt 22. A cleaning backup roller 72 disposed inside the loop of the intermediate transfer belt 22 backs up the cleaning of the belt by the belt cleaning device 71 from the inside of the loop.

  The fixing device 40 is provided with a fixing roller 45 including a heat source 45a such as a halogen lamp, and a pressure roller 47 that rotates while contacting the fixing roller 45 with a predetermined pressure. A fixing nip is formed by the pressure roller 47. The recording paper fed into the fixing device 40 is sandwiched between the fixing nips such that the unfixed toner image carrying surface is in close contact with the fixing roller 45. Then, the toner in the toner image is softened by the influence of heating and pressurization, and the full-color image is fixed.

  When the single-sided print mode is set, the recording paper discharged from the fixing device 40 is discharged to the outside as it is. Then, it is stacked on a stack portion constituted by the upper surface of the upper cover 56 of the housing.

  As shown by an arrow A in FIG. 1, the upper cover 56 of the housing of the printer 100 is supported so as to be rotatable about the upper cover shaft member 51, and rotates in the counterclockwise direction in FIG. Thus, the printer 100 is opened with respect to the housing. Then, the upper opening of the housing of the printer 100 is largely exposed. The optical writing unit 27 is also supported so as to be rotatable around the upper cover shaft member 51. By rotating the optical writing unit 27 in the counterclockwise direction in FIG. The upper surface of (K, C, M, Y) can be exposed.

  The process unit 26 (K, C, M, Y) is attached / detached by opening the upper cover 56 and the optical writing unit 27. Specifically, the upper cover 56 and the optical writing unit 27 are opened to expose the upper surface of the process unit 26 (K, C, M, Y), and then the process unit 26 (K, C, M, Y). It is taken out from the main body by pulling out vertically upward.

  The process unit 26 with high attachment / detachment frequency is performed with the upper cover 56 and the optical writing unit 27 opened, so that the housing can be viewed from the upper side without taking an unreasonable posture such as squatting, bending the waist, or bending over. The attachment / detachment operation can be confirmed. Therefore, it is possible to reduce the work load and to suppress the occurrence of operation mistakes.

  In this embodiment, the process unit 26 including the photosensitive unit 10 and the developing unit 23 is detachable from the printer 100 main body. However, the developing unit 23 and the photosensitive unit 10 are separately attached to the printer 100 main body. It may be removable.

Next, features of the present embodiment will be described.
FIG. 3 is a schematic cross-sectional view of the driving device 110 that drives the developing roller 81.
As shown in FIG. 3, the drive device 110 includes a drive motor 111 and a speed reduction member 116. The speed reduction member 116 has an inner tooth portion 116a and an outer tooth portion 116b, and a motor gear 111a formed on the outer periphery of the motor shaft 111g of the drive motor 111 meshes with the inner teeth of the inner tooth portion 116a. Further, a developing gear 118 attached to a developing drive shaft 81a connected to the shaft of the developing roller 81 via a joint meshes with the external teeth of the external tooth portion 116b.

  The deceleration member 116 is rotatably supported by a support shaft 117 that is caulked and fixed to a first face plate 112 and a second face plate 113 that is disposed to face the first face plate 112. The developing drive shaft 81a is rotatably supported by the second face plate 113 via a bearing 81b. The drive motor 111 is attached to the motor holding face plate 114. The first face plate 112 and the motor holding face plate 114 are positioned by positioning pins 115 provided on the second face plate 113.

FIG. 4 is a schematic perspective view of the drive motor 111.
In the present embodiment, an outer rotor type DC brushless motor is used as the drive motor 111. The drive motor 111 includes a control board 111c having a connector 111d and the like, and a mounting face plate 111e having screw insertion holes 111f at four corners. A cylindrical motor positioning portion 111b is provided on a motor shaft 111g provided so as to penetrate the control board 111c.

  The outer rotor type DC brushless motor has a stable rotational performance, and by using the outer rotor type DC brushless motor as the drive motor 111, the developing roller 81 can be rotated well at a constant speed.

  As shown in FIG. 3, the drive motor 111 is positioned on the motor holding surface plate 114 by fitting the motor positioning portion 111 b into the positioning hole portion 114 a provided in the motor holding surface plate 114. Then, the drive motor 111 is positioned and fixed to the motor holding face plate 114 by inserting a screw 119 into a screw insertion hole 111f provided in the attachment face plate 111e and screwing it to the motor holding face plate 114.

  The driving force of the driving motor 111 is transmitted to the internal gear portion 116a via a motor gear 111a formed on the motor shaft 111g. Then, it is transmitted to the developing gear 118 that meshes with the external tooth portion 116b of the deceleration member 116, and is transmitted to the developing roller 81 through the developing drive shaft 81a, so that the developing roller is rotationally driven.

  In recent years, it has been desired to further reduce the noise of the device, and it is desired to reduce the diameter of the internal gear portion 116a of the speed reduction member 116. By reducing the diameter of the internal tooth portion 116a, the meshing rate with the motor gear 111a can be improved, and vibration and noise can be suppressed. When the diameter of the internal tooth portion 116a is reduced, the support shaft 117 that rotatably supports the speed reduction member 116 is disposed close to the motor shaft 111g.

  Conventionally, the drive motor 111 is positioned and held on the first face plate 112 that is a holding member that holds the support shaft 117 that supports the speed reduction member 116 that is an internal gear. In this case, the motor positioning portion 111b is attached to the first face plate 112. It is necessary to provide a positioning hole for fitting. The support shaft 117 is provided with a fitting hole in the first face plate 112 serving as a holding member, and the tip of the support shaft 117 is fitted into the fitting hole, but when the diameter of the internal tooth portion 116a is reduced, The distance between the fitting hole and the positioning hole will be short. The first face plate 112 is made of sheet metal, and the positioning hole and the fitting hole are usually formed by press working. Therefore, when forming each hole by such press work, each hole cannot be formed accurately unless it is separated by 2 to 3 mm or more. As a result, the fitting hole cannot be formed sufficiently close to the positioning hole portion, the support shaft 117 cannot be disposed sufficiently close to the motor shaft 111g, and there is a limit to the reduction in the diameter of the internal tooth portion 116a.

  However, in the present embodiment, a motor holding face plate 114 is provided separately from the first face plate 112 that holds the support shaft 117, and the motor positioning portion 111b is fitted into the motor holding face plate 114 so that the drive motor 111 is positioned. It was to so. In this case, as shown in FIG. 3, the first face plate 112 needs to be provided with a through hole 112 a through which the motor shaft 111 g of the drive motor 111 passes. However, the diameter of the motor shaft 111g is smaller than the diameter of the positioning portion 111b, and the through hole 112a may be a hole that does not interfere with the motor shaft 111g. Therefore, the hole may be sufficiently smaller than the diameter of the positioning hole portion into which the positioning portion 111b is fitted, and the support shaft 117 can be disposed closer to the motor shaft 111g than when the positioning hole portion is provided in the first face plate 112. . Thereby, compared with the case where the positioning hole part is provided in the 1st face plate 112, the diameter of the internal gear part 116a of the deceleration member 116 can fully be reduced in diameter, and the meshing rate with the motor gear 111a is fully improved. be able to. As a result, the meshing vibration and noise between the motor gear 111a and the internal teeth of the internal tooth portion 116a can be suppressed, and the noise of the apparatus can be reduced. Further, the influence of the image due to the meshing vibration between the motor gear 111a and the internal teeth of the internal tooth portion 116a can be suppressed, and a high-quality image can be obtained.

  Further, by providing the motor holding face plate 114 separately from the first face plate 112 that holds the support shaft 117, the support shaft can be moved to a position where a part of the support shaft 117 overlaps the positioning portion 111 b when viewed from the axial direction. 117 can be disposed close to the motor shaft 111g. Specifically, as shown in FIG. 3, when the distance between the support shaft 117 and the motor shaft 111g is S, the radius of the positioning portion 111b is D, and the radius of the support shaft 117 is d, S <D + d. Thus, the support shaft 117 can be arranged. When the positioning portion 111b of the drive motor 111 is fitted and positioned in the first face plate 112, it is impossible to dispose the support shaft 117 so as to satisfy the relationship of S <D + d. However, by positioning the drive motor 111 on a motor holding face plate 114 that is different from the first face plate 112, the support shaft 117 can be arranged so as to satisfy the relationship of S <D + d. The diameter can be made sufficiently small.

  In addition, by making the gear meshing with the motor gear 111a an internal gear, the meshing portion with the motor gear 111a can be covered with the internal gear portion 116a, and the meshing noise can be shielded by the internal gear portion 116a. Further, since the motor side of the cylindrical inner tooth portion 116a is open, the meshing noise leaks from there. However, in the present embodiment, since the first face plate 112 is disposed so as to face the opening of the internal tooth portion 116a, this meshing noise can be prevented from leaking from the first face plate 112 to the outside of the apparatus.

  In the present embodiment, the first face plate 112 and the motor holding face plate 114 are positioned by the positioning pins 115. In this way, by positioning the first face plate 112 and the motor holding face plate 114 on the same member, the component tolerance is increased as compared with the case where the first face plate 112 and the motor holding face plate 114 are positioned on different members, respectively. It is possible to suppress a decrease in accuracy due to. As a result, the motor gear and the internal gear portion 116a can be meshed with high accuracy, and the occurrence of meshing vibration and the like can be suppressed.

  Further, in the present embodiment, the internal teeth of the internal tooth portion 116a are set as teeth. By using helical teeth, the meshing rate between the internal teeth and the motor gear 111a can be further increased, and meshing vibration and noise can be further suppressed. Moreover, it is preferable that the direction of the thrust force generated during the rotational drive is the motor side with respect to the twisting direction of the internal teeth of the helical teeth. Specifically, when the motor shaft is viewed in the axial direction from the developing roller side, when the rotation direction of the motor shaft is counterclockwise, the helical teeth are twisted to the right, and when the rotation direction of the motor shaft is clockwise. The helical teeth are left-twisted. In other words, the helical teeth are twisted so that the developing roller side of the helical teeth is located downstream of the motor side in the rotational direction. As a result, a thrust force toward the developing roller acts on the motor gear 111a during rotational driving, and the drive motor 111 can be pressed against the motor holding face plate 114. Thereby, the attitude | position of the drive motor 111 can be maintained and generation | occurrence | production of meshing vibration etc. can be suppressed favorably.

  Further, the external teeth of the external tooth portion 116b are also helical teeth, and are twisted in a direction opposite to the thrust force of the internal teeth, that is, the thrust force acting on the developing roller side. Specifically, the helical teeth of the external tooth portion 116b are set in the same twisting direction as the motor gear 111a. As a result, the thrust force of the inner tooth portion 116a can be canceled out by the thrust force of the outer tooth portion 116b, and the speed reduction member 116 moves to the drive motor side and rotates while being in contact with the first face plate 112. Can be prevented. Accordingly, the developing roller can be driven to rotate without causing uneven rotation by favorably driving the deceleration member 116 to rotate.

  In the present embodiment, the reduction member 116 is provided with a reinforcing protrusion 116c for reinforcing the internal tooth portion 116a. In the present embodiment, a reinforcing protrusion 116c is provided on the outer peripheral surface of a disk-like connecting portion 116e that is orthogonal to the axial direction connecting the cylindrical inner tooth portion 116a and the attaching portion 116d through which the support shaft 117 passes. ing. When the internal teeth are helical teeth as in this embodiment, a force is applied to the internal teeth portion 116a in a direction inclined with respect to the axial direction by meshing with the motor gear 111a. As a result, a force is applied to the cylindrical inner tooth portion 116a in the axially oblique direction, and a force that tilts the connecting portion 116e with respect to the axial direction is applied. If the connecting portion 116e is deformed by the force, the meshing between the internal teeth and the motor gear 111a is affected, and meshing vibration may occur or abnormal tooth wear may occur. However, in this embodiment, since the connection part 116e is reinforced with the reinforcement protrusion 116c, it can suppress that the connection part 116e deform | transforms, and it can suppress a meshing vibration and abnormal wear of a tooth | gear. Thereby, it is possible to suppress the occurrence of an abnormal image such as banding in the image due to the meshing vibration, and it is possible to maintain a high-quality image. Moreover, in this embodiment, the reinforcement protrusion 116c is formed in the location used as the outer peripheral surface of the internal tooth part 116a of the connection part 116e. This is because in the present embodiment, since the diameter of the inner tooth portion 116a is reduced, it is difficult to form the connecting portion 116e on the inner peripheral surface of the inner tooth portion 116a.

  Further, as shown in FIG. 5, the motor holding face plate 114 may be attached separately from the first face plate 112.

In addition, as shown in FIG. 6, photosensitive member gears 121 a and 121 b that are drive transmission members that transmit driving force to the photosensitive member 24 may be arranged in the gap between the motor holding face plate 114 and the first face plate 112. Good.
As shown in FIG. 6, the first photoconductor gear 121a and the second photoconductor gear 121b mesh with the motor gear 111a on the base side of the motor shaft 111g of the drive motor 111. Further, the internal gear 126a of the speed reduction member 126 meshes with the motor gear 111a on the tip end side of the motor shaft 111g. Further, the speed reduction member 126 shown in FIG. 6 has outer teeth 126b formed on the outer periphery of a cylindrical portion having inner teeth formed on the inner periphery, and the developing gear of the outer teeth 126b is engaged. In this way, by forming the outer teeth 126b on the outer periphery of the cylindrical portion having the inner teeth formed on the inner periphery, the speed reducing member can be shortened in the axial direction as compared with the speed reducing member 116 shown in FIG. Therefore, the apparatus can be reduced in size.

  Each of the photoconductor gears 121a and 121b is a large-diameter external gear and is attached to the photoconductor drive shaft 24a so as to rotate integrally with the photoconductor drive shaft 24a connected to the photoconductor 24 via a joint. It has been. The photosensitive member drive shaft 24 a is rotatably supported by the first face plate 112 via a bearing 124. The second photoconductor gear 121b transmits the driving force to the photoconductor adjacent to the photoconductor 24 to which the first photoconductor gear 121a transmits the driving force.

FIG. 7 is a perspective view of FIG. 6 with the first face plate 112 removed.
As shown in FIG. 7, each of the photoconductor gears 121 a and 121 b is disposed so as to partially overlap the speed reduction member 126 in the axial direction. Thus, by arranging the photoconductor gears 121a and 121b in the gap between the motor holding face plate 114 and the first face plate 112, the space can be used effectively and the apparatus can be downsized. . Further, the noise generated by the engagement between the photoconductor gears 121a and 121b and the motor gear can be shielded by the first face plate 112 and the motor holding face plate 114, so that the apparatus can be silenced.

  As shown in FIG. 6, the tip A of the motor shaft 111g is tapered. Thus, by tapering the tip A of the motor shaft 111g, when the motor shaft 111g of the drive motor 111 is inserted from the axial direction, the taper of the tip A is slightly shifted even in the radial direction. By being guided, it can mesh with the inner teeth of the respective photoreceptor gears 121a and 121b and the speed reduction member 126. As a result, the motor can be easily assembled.

  In FIG. 6, an internal gear is used for driving transmission of the developing roller 81 that rotates at a higher speed than the photosensitive member 24. As described above, the internal gear is used for the drive transmission of the developing roller 81 serving as the drive transmission path with a small reduction ratio, thereby reducing the noise compared to the case where the internal gear is used for the drive transmission of the photoconductor with a large reduction ratio. Can be achieved.

FIG. 8 shows a modification of the driving device that transmits the driving force to the photosensitive member and the developing roller.
In FIG. 8, a gear train for transmitting drive to the photosensitive member is disposed in the gap between the first face plate 112 and the motor holding face plate 114. In FIG. 8, a photoreceptor idler gear 122 and a photoreceptor gear 121 are arranged in the gap between the first face plate 112 and the motor holding face plate 114. The photoreceptor idler gear 122 is rotatably supported by an idler support shaft 123 supported by the first face plate 112 and the motor holding face plate 114, and meshes with the motor gear on the base side of the motor shaft 111g. The photoconductor gear 121 meshes with the photoconductor idler gear 122, and similarly to the above, the photoconductor drive shaft 24a rotates integrally with the photoconductor drive shaft 24a connected to the photoconductor 24 via a joint. Is attached. The photosensitive member drive shaft 24 a is rotatably supported by the first face plate 112 via a bearing 124.

  Also in the configuration shown in FIG. 8, by arranging the photoconductor gear 121 and the photoconductor idler gear 122 in the gap between the motor holding face plate 114 and the first face plate 112, the space can be used effectively, and the apparatus Can be miniaturized. Further, the first face plate 112 and the motor holding face plate 114 can shield the noise generated by the meshing between the photoconductor gear 121 and the photoconductor idler gear 122 and the meshing noise generated between the motor gear and the photoconductor idler gear 122. It is possible to reduce the noise of the device.

What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.
(Aspect 1)
A drive motor 111, an internal gear such as a speed reduction member 116 that meshes with the motor gear 111a of the drive motor 111, a support shaft 117 that supports the internal gear, and a holding member such as the first face plate 112 that holds the support shaft 117. In the drive device 110 provided, the drive motor 111 was positioned on a member (in this embodiment, the motor holding face plate 114) different from the holding member.
According to this, as described in the embodiment, the drive motor 111 is different from the holding member such as the first face plate 112 that holds the support shaft of the internal gear (in this embodiment, the motor holding face plate). 114), it is not necessary to provide the motor-positioned portion in which the positioning portion 111b of the drive motor 111 provided coaxially with the motor shaft 111g fits in the holding member. As a result, the support shaft can be disposed closer to the motor shaft than in the configuration in which the motor positioned portion is provided on the holding member. This makes it possible to reduce the diameter of the internal gear as compared with the configuration in which the motor positioning portion is provided on the holding member, and the noise of the apparatus can be reduced.

(Aspect 2)
In (Aspect 1), the motor shaft 111g of the drive motor 111 passes through a holding member such as the first face plate 112.
According to this, as described in the embodiment, the meshing noise between the internal teeth of the internal gear such as the speed reduction member 116 and the motor gear 111a can be shielded by the holding member such as the first face plate 112. Thereby, it can suppress that the meshing noise of the internal gear of an internal gear and the motor gear 111a leaks outside.

(Aspect 3)
In (Aspect 1) or (Aspect 2), the member where the drive motor 111 such as the motor holding face plate 114 is positioned and the holding member such as the first face plate 112 are positioned by the same member.
According to this, as described in the embodiment, the holding member such as the first face plate 112 and the member on which the driving motor 111 such as the motor holding face plate 114 is positioned are respectively positioned on different members. In addition, it is possible to suppress a decrease in accuracy due to accumulation of component tolerances. Thereby, a motor gear and an internal tooth can be meshed | engaged accurately and generation | occurrence | production of meshing vibration etc. can be suppressed.

(Aspect 4)
In any one of (Aspect 1) to (Aspect 3), the drive motor 111 has a positioning portion 111b coaxial with the motor shaft 111g and larger in diameter than the motor shaft 111g, and the motor shaft 111g and the support shaft The inter-axis distance S with 117 is larger than the value obtained by adding the radius D of the positioning portion 111b and the radius d of the support shaft 117.
According to this, as described in the embodiment, the drive motor 111 is positioned on a member (in this embodiment, the motor holding face plate 114) different from the holding member, so that it is supported when viewed from the axial direction. The support shaft 117 can be disposed so that at least a part of the shaft 117 overlaps the positioning portion 111b, and the internal gear can be sufficiently reduced in diameter.

(Aspect 5)
In any one of (Aspect 1) to (Aspect 4), the reinforcing protrusion 116c is provided on the internal gear such as the speed reduction member 116.
According to this, as described in the embodiment, the strength of the internal gear such as the speed reduction member 116 can be increased, and the deformation of the speed reduction member 116 is suppressed when the driving force is transmitted from the motor gear 111a. can do. Thereby, it is possible to suppress the occurrence of abnormal tooth wear and meshing vibration.

(Aspect 6)
In any one of (Aspect 1) to (Aspect 5), the internal teeth of the internal gear such as the speed reduction member 116 are formed in a tooth shape.
According to this, as explained in the embodiment, the meshing rate with the motor gear 111a can be increased, and vibration and noise can be suppressed.

(Aspect 7)
In (Aspect 6), the helical teeth are twisted so that the side opposite to the drive motor side is located downstream of the motor side in the rotation direction of the motor gear.
According to this, as described in the embodiment, a thrust force directed to the side opposite to the drive motor is generated in the motor gear, and the drive motor 111 is pressed against a member for positioning the drive motor such as the motor holding face plate 114. Can do. Thereby, the attitude | position of the drive motor 111 can be maintained and generation | occurrence | production of meshing vibration etc. can be suppressed favorably.

(Aspect 8)
In any one of (Aspect 1) to (Aspect 7), an internal gear such as a speed reduction member has a cylindrical portion in which inner teeth are formed on the inner peripheral surface, and external teeth or the like are formed on the outer peripheral surface of the cylindrical portion. A drive transmission part was formed.
According to this, as described with reference to FIG. 6, the speed reduction member can be shortened in the axial direction as compared with the case where the internal tooth portion and the external tooth portion are arranged side by side in the axial direction. Can be achieved.

(Aspect 9)
In any one of (Aspect 1) to (Aspect 8), an internal gear such as a speed reduction member includes a helical tooth-shaped internal tooth and a helical tooth-shaped external tooth, and the helical tooth of the external tooth The twisting direction was the same as the twisting direction of the helical teeth of the motor gear 111a.
According to this, as described in the embodiment, the direction of the thrust force of the external teeth can be opposite to the direction of the thrust force of the internal teeth, and the thrust force of the internal teeth is canceled by the thrust force of the external teeth. Can do. Accordingly, it is possible to prevent the internal gear such as the speed reduction member 116 from moving to the drive motor side and rotating while contacting the holding member such as the first face plate 112. As a result, the driven transmission member such as the developing roller can be driven to rotate without causing uneven rotation by favorably driving the internal gear.

(Aspect 10)
In any one of (Aspect 1) to (Aspect 9), the member on which the drive motor 111 such as the motor holding face plate 114 is positioned is disposed to face the holding member such as the first face plate 112 with a predetermined gap. A drive transmission member such as the photoconductor gear 121 is disposed in the gap between the member where the drive motor 111 is positioned and the holding member.
According to this, as described with reference to FIGS. 6 and 7, the noise generated by the engagement between the drive transmission member such as the photoconductor gear 121 and the motor gear 111a is reduced by the holding member such as the first face plate 112 and the motor holding. It can be shielded by a member on which the drive motor 111 such as the face plate 114 is positioned, so that the apparatus can be quiet.

(Aspect 11)
In (Aspect 10), the drive transmission member such as the photoconductor gear 121 disposed in the gap between the member where the drive motor 111 such as the motor holding face plate 114 is positioned and the holding member such as the first face plate 112 is the drive motor 111. Meshes with the motor gear 111a.
According to this, two drive transmission paths can be formed with one drive motor.

(Aspect 12)
In (Aspect 11), the reduction ratio between the internal gear such as the speed reduction member and the motor gear 111a is in the gap between the member where the drive motor such as the motor holding face plate 114 is positioned and the holding member such as the first face plate 112. It is smaller than the reduction ratio between the drive transmission member such as the arranged photoconductor gear 121 and the motor gear 111a.
According to this, as described with reference to FIGS. 6 and 7, it is possible to reduce the noise as compared with the case where the internal gear is used for drive transmission with a large reduction ratio.

(Aspect 13)
In (Aspect 11) or (Aspect 12), via a drive transmission member such as a photoconductor gear disposed in a gap between a member where a drive motor such as the motor holding face plate 114 is positioned and a holding member such as the first face plate 112. The driven transmission member to which the driving force is transmitted is the photoconductor 24.
According to this, the photosensitive member 24 can be driven while suppressing noise.

(Aspect 14)
In any one of (Aspect 1) to (Aspect 13), the driven transmission member to which a driving force is transmitted via an internal gear such as a speed reduction member is the developing roller 81.
According to this, the developing roller 81 can be driven while suppressing noise.

(Aspect 15)
In any one of (Aspect 1) to (Aspect 14), the tip end portion of the motor shaft 111g of the drive motor is tapered so that the diameter decreases toward the tip end.
According to this, as described with reference to FIG. 6, when the drive motor 111 is assembled, even if the drive motor 111 is slightly displaced in the radial direction, it is guided by the tapered shape at the tip of the motor shaft 111g, The motor gear 111a formed on the outer periphery of the shaft can be meshed with the internal teeth of the internal gear. Thereby, the drive motor 111 can be easily assembled.

(Aspect 16)
In any one of (Aspect 1) to (Aspect 15), the drive motor 111 is an outer rotor type brushless motor.
According to this, as described in the embodiment, the drive motor 111 rotates stably, and the driven transmission member such as the developing roller 81 can be rotated well at a constant speed.

(Aspect 17)
The image forming apparatus includes the driving device according to any one of (Aspect 1) to (Aspect 16).
According to this, vibration and meshing noise are suppressed, and the device can be made quieter.

10: Photoconductor unit 21: Secondary transfer roller 22: Intermediate transfer belt 23: Development unit 24: Photoconductor 24a: Photoconductor drive shaft 81: Development roller 81a: Development drive shaft 110: Drive device 111: Drive motor 111a : Motor gear 111b:
111g: Motor shaft 112: First face plate 112a: Through hole 113: Second face plate 114: Motor holding face plate 114a: Positioning hole portion 115: Positioning pin 116 Deceleration member 116a: Internal tooth portion 116b: External tooth portion 116c: Reinforcing protrusion 116e : Connecting portion 117: support shaft 118: developing gears 121, 121 a, 121 b: photoconductor gear 122: photoconductor idler gear 123: idler support shaft 126: reduction member 126 a: internal tooth 126 b: external tooth A: tip D: positioning portion Radius d: Radius of support shaft S: Distance between shafts

JP 2014-169723 A

Claims (17)

A drive motor;
An internal gear meshing with the motor gear of the drive motor;
A support shaft for supporting the internal gear;
In a drive device comprising a holding member that holds the support shaft,
The drive apparatus characterized by positioning the said drive motor in the member different from the said holding member. The drive device according to claim 1,
A drive device, wherein a motor shaft of the drive motor penetrates the holding member. The drive device according to claim 1 or 2,
The drive device characterized in that the member for positioning the drive motor and the holding member are positioned by the same member. The drive device according to any one of claims 1 to 3,
The drive motor has a positioning portion that is coaxial with the motor shaft and has a diameter larger than the diameter of the motor shaft,
The drive apparatus according to claim 1, wherein an inter-axis distance between the motor shaft and the support shaft is smaller than a value obtained by adding a radius of the positioning portion and a radius of the support shaft. The drive device according to any one of claims 1 to 4,
A drive device characterized in that a reinforcing projection is provided on the internal gear. The drive device according to any one of claims 1 to 5,
A driving device characterized in that the internal gear of the internal gear has a tooth shape. The drive device according to claim 6, wherein
The drive device characterized in that the helical teeth are twisted so that the side opposite to the drive motor side is located on the downstream side of the motor gear in the rotation direction of the motor gear. The drive device according to any one of claims 1 to 7,
The internal gear includes a cylindrical portion having an inner tooth formed on an inner peripheral surface, and a drive transmission portion is formed on the outer peripheral surface of the cylindrical portion. The drive device according to any one of claims 1 to 8,
The internal gear includes a helical tooth-shaped internal tooth and a helical tooth-shaped external tooth,
2. A driving apparatus according to claim 1, wherein the helical direction of the external teeth is the same as the helical direction of the motor gear. The drive device according to any one of claims 1 to 9,
The member on which the drive motor is positioned is disposed to face the holding member with a predetermined gap,
A drive device, wherein a drive transmission member is disposed in a gap between a member on which the drive motor is positioned and the holding member. The drive device according to claim 10, wherein
The drive device, wherein a drive transmission member disposed in a gap between a member where the drive motor is positioned and the holding member meshes with a motor gear of the drive motor. The drive device according to claim 11, wherein
The reduction ratio between the internal gear and the motor gear is smaller than the reduction ratio between the motor transmission and the drive transmission member disposed in the gap between the member where the drive motor is positioned and the holding member. A drive device characterized by that. The drive device according to claim 11 or 12,
A driving device, wherein a driven transmission member to which a driving force is transmitted via a driving transmission member disposed in a gap between a member on which the driving motor is positioned and the holding member is a photoconductor. The drive device according to any one of claims 1 to 13,
The driving device, wherein the driven transmission member to which the driving force is transmitted via the internal gear is a developing roller. The drive device according to any one of claims 1 to 14,
The drive device according to claim 1, wherein a tip end portion of the motor shaft of the drive motor has a tapered shape whose diameter decreases toward the tip end. The drive device according to any one of claims 1 to 15,
The drive apparatus according to claim 1, wherein the drive motor is an outer rotor type brushless motor.   An image forming apparatus comprising the driving device according to claim 1.

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