JP2007224960A - Constant velocity joint and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a constant velocity joint reduced in weight and operating noise, eliminating the need of filling an annular space with grease, and capable of maintaining the constant velocity with a rotating drive force. <P>SOLUTION: The female side joint 120 of this constant velocity joint 110 is formed in a double layer structure in which an innermost layer 122a the outer ring 122 of which is made of a resin material forming the inner peripheral surface and a metal layer 122b made of a metal material on the outer side of the innermost layer. With this structure, the weight of the female side joint 120 is reduced more than that of the conventional structure in which the entire part of the outer ring 122 is made of a metal material. Even if the annular space 124 is filled with grease, the operating noise is reduced while the female side joint 120 and a male side joint 150 are smoothly rotated. The rotating drive force is kept constant by suppressing the deflection of the outer ring 122 in the normal direction due to the slidable contact thereof with balls 152. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a constant velocity joint that transmits a constant velocity rotational force between two rotating bodies arranged in the axial direction in a relationship with a declination, and an image forming apparatus such as a copying machine, a facsimile, and a printer using the same. is there.

  Conventionally, a constant velocity joint is known as one of drive transmission mechanisms for transmitting rotational torque of a drive shaft of an automobile to an axle. The constant velocity joint can transmit a driving force between them at a constant speed in the rotational direction while allowing a skew between the driving side driving shaft and the driven side driving shaft that are aligned in the axial direction. It is a drive transmission mechanism widely used in various industrial machines, not limited to automobiles.

  In general, the constant velocity joint includes a first rotating body and a second rotating body, which are aligned in the axial direction, like the one described in Patent Document 1, for example. The first rotating body has a cup portion having a cup shape that opens one end side in the axial direction in the annular space by the gap between the outer ring and the inner ring inside thereof, and closes the other end side. In the cup portion, a plurality of grooves arranged in the circular direction are formed on the inner surface of the outer ring and the outer surface of the inner ring that face each other with an annular space extending in the axial direction. On the other hand, the second rotator has a cylindrical sphere holder inserted into the annular space of the first rotator. A plurality of through holes are formed on the cylindrical peripheral wall of the spherical body holding portion so as to be arranged in the circumferential direction, and a ball is held in each through hole. The second rotating body is inserted into the annular space of the first rotating body so that these balls are engaged in grooves formed on the inner surface of the outer ring and the outer surface of the inner ring of the first rotating body. In this state, when one of the first rotating body and the second rotating body rotates on the driving side, the rotational force is transmitted to the other through a plurality of balls engaged with the grooves.

Japanese Patent Publication No. 52-34699

  The conventional constant velocity joint having such a configuration has a drawback that the weight is large because the first rotating body and the second rotating body are made of metal. In addition, there is a drawback that the operation sound becomes louder due to the friction between the ball and the outer ring or the inner ring. Furthermore, grease is filled in the annular space of the first rotating body for the purpose of smoothly rolling the ball. However, there is a concern about grease contamination to the surrounding environment due to leakage of this grease. As a result, it has been difficult to apply to office machines, audio equipment, medical equipment, household appliances, food manufacturing equipment, and the like.

  Therefore, the inventors made a prototype of a constant velocity joint in which the outer ring is formed of a synthetic resin (polyacetal resin) having a very small frictional resistance. Then, even if grease was not filled in the annular space, the first rotating body and the second rotating body could be smoothly rotated, and the operating noise could be reduced compared to that made of metal. However, the rotational force could not be transmitted at a constant speed. As a result of diligent research on the cause, it was found that this is because the outer ring made of a resin having low rigidity is bent in the normal direction along with the friction with the ball.

  The present invention has been made in view of the above background, and an object thereof is to provide the following constant velocity joint and an image forming apparatus using the same. That is, it is to provide a constant velocity joint that can reduce the weight and operation noise as compared with the prior art, does not require filling the annular space with grease, and can maintain the constant velocity of the rotational driving force.

In order to achieve the above object, the invention of claim 1 is a cup portion having a cup shape that opens one end side in the axial direction in an annular space formed by a gap between an outer ring and an inner ring inside thereof and closes the other end side. And a first rotating body having a plurality of grooves provided on at least one of the inner surface of the outer ring and the outer surface of the inner ring so as to be arranged in a circular direction while extending in the axial direction, and along the circumferential direction. A plurality of through holes provided in a cylindrical peripheral wall so as to be arranged in a row, each of which has a second rotating body having a sphere holding portion for holding the sphere, and the sphere holding portion is inserted into the annular space and the sphere holding In a state where the plurality of spheres held by the section are engaged with the plurality of grooves in the annular space, either one of the first rotator and the second rotator is interposed through the plurality of spheres. A constant velocity joint that transmits rotational driving force to the other It, the outer ring is characterized in that forming a multilayer structure having a innermost layer made of a resin material forming the inner peripheral surface, and a metal layer made from the outside of the metal material than this.
The invention according to claim 2 is the constant velocity joint according to claim 1, wherein the outer ring has a two-layer structure including the innermost layer made of resin and the outermost layer made of metal. It is.
According to a third aspect of the present invention, in the constant velocity joint of the second aspect, as the cup portion, the innermost layer and the inner ring are integrally formed of the same resin material inside a cylindrical metal body constituting the outermost layer. What used the thing which fitted the cup base | substrate was used.
The invention of claim 4 is the constant velocity joint of claim 3, wherein the cylindrical metal body is formed by integrally forming a shaft portion extending on the central axis of the same metal material as the cylinder. It is characterized by.
The invention according to claim 5 is the constant velocity joint according to any one of claims 1 to 4, wherein the spherical body holding portion is made of a resin material.
A sixth aspect of the present invention is the constant velocity joint according to any one of the first to fifth aspects, wherein the resin material is a material that can be injection molded.
According to a seventh aspect of the present invention, there is provided a latent image carrier that carries a latent image on a surface that moves endlessly, a latent image forming unit that forms a latent image on the surface, and a developer carried on the surface that moves endlessly. A developing member for developing a latent image on the latent image carrier, and a transfer unit for transferring a visible image on the latent image carrier obtained by development to the surface of the surface endless moving body or a recording member held by the surface. And a drive transmission mechanism that transmits a driving force from a drive source to at least one of the latent image carrier, the developing member, and the surface endless moving body. A high speed joint is provided.
According to an eighth aspect of the present invention, in the image forming apparatus of the seventh aspect, a driving motor having a driving rotation shaft is used as the driving source, and the photosensitive image rotating about the driven rotation shaft is used as the latent image carrier. The driving rotary shaft and the driven rotary shaft are connected by the constant velocity joint using a body.
According to a ninth aspect of the present invention, in the image forming apparatus according to the eighth aspect of the present invention, the photosensitive member is one in which the driven rotating shaft is passed through and engaged with a central hole bored in the axial direction. To do.
According to a tenth aspect of the present invention, in the image forming apparatus according to the eighth or ninth aspect, any one of the first rotating body or the second rotating body and the driving rotation shaft of the drive motor is set to the other. On the other hand, both of them are connected in the axial direction by press-fitting in the axial direction.
According to an eleventh aspect of the present invention, in the image forming apparatus according to any one of the eighth to tenth aspects, the photosensitive member is connected to the constant velocity joint fixed to the apparatus main body when the driven rotation shaft is connected. Is provided with a positioning mechanism for positioning the sensor in the photosensitive body axial direction with respect to the apparatus main body.

  In these inventions, since the inner peripheral surface of the outer ring of the first rotating body is formed of a resin material, the weight of the first rotating body is reduced compared to the conventional configuration in which all of the outer ring is formed of a metal material. Can be small. In addition, since the inner peripheral surface of the outer ring is made of a resin material, the first rotating body and the second rotating body can be obtained without filling the annular space with grease, as has been clarified in the prototype of the present inventors. The operation sound can be reduced as compared with the conventional configuration formed of a metal material. Furthermore, the outer ring has a multi-layered structure, and the outer layer of the inner ring that forms the inner peripheral surface of the outer ring is made of a metal material having rigidity higher than that of the resin material. It is possible to maintain the constant speed of the rotational driving force by suppressing the bending in the direction.

  Hereinafter, an embodiment in which the present invention is applied to an electrophotographic color laser printer (hereinafter simply referred to as a printer) as an image forming apparatus will be described. FIG. 1 is a schematic configuration diagram illustrating a printer according to the present embodiment. This laser printer includes four sets of process units 1Y, M, C, and K for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). Y, M, C, and K attached to the numbers of the respective symbols indicate members for yellow, magenta, cyan, and black (the same applies hereinafter). In addition to the process units 1Y, 1M, 1C, and 1K, an optical writing unit 10, a transfer unit 11, a registration roller pair 19, three paper feed cassettes 20, a fixing unit 21, and the like are disposed.

  The optical writing unit 10 includes four optical writers. Each optical writer includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates a laser beam on the surface of a photoconductor described later based on image data.

  FIG. 2 is an enlarged configuration diagram showing the yellow process unit 1Y among the four sets of process units 1Y, 1M, 1C, and 1K. Since the other process units 1M, 1C, and 1K have the same configuration as the yellow process unit 1Y, their descriptions are omitted. In the figure, a process unit 1Y has a drum-shaped photoreceptor 2Y, a charger 30Y, a developing device 40Y, a drum cleaning device 48Y, and the like.

  The charger 30Y has a charging roller to which a charging bias is applied in contact with or close to the photosensitive member 2Y, and discharges between the charging roller and the photosensitive member 2Y to uniformly charge the surface of the photosensitive member. . The surface of the photosensitive member 2Y that has been subjected to the charging process is irradiated with the laser beam modulated and deflected by the optical writing unit 10 while being scanned. Then, an electrostatic latent image is formed on the drum surface. The formed electrostatic latent image is developed by the developing device 40Y to become a Y toner image.

  The developing device 40Y has a developing sleeve 42Y as a developing member disposed so as to expose a part of the peripheral surface from the opening of the casing. Further, it also includes a first transport screw 43Y, a second transport screw 44Y, a developing doctor 45Y, a toner concentration sensor (hereinafter referred to as T sensor) 46Y, and the like.

  A two-component developer containing a magnetic carrier and negatively chargeable Y toner is accommodated in the casing. The two-component developer is frictionally charged while being agitated and conveyed by the first conveying screw 43Y and the second conveying screw 44Y, and then carried on the surface of the developing sleeve 42Y. Then, after the layer thickness is regulated by the developing doctor 45Y, the layer is conveyed to a developing region facing the photoreceptor 2Y, where Y toner is attached to the electrostatic latent image on the photoreceptor 2Y. This adhesion forms a Y toner image on the photoreceptor 2Y. The two-component developer that has consumed Y toner by development is returned to the casing as the developing sleeve 42Y rotates.

  A partition wall 47Y is provided between the first transport screw 43Y and the second transport screw 44Y. The partition wall 47Y separates the first supply unit that accommodates the developing sleeve 42Y, the first conveyance screw 43Y, and the like and the second supply unit that accommodates the second conveyance screw 44Y in the casing. The first conveying screw 43Y is driven to rotate by a driving means (not shown), and supplies the two-component developer in the first supply unit to the developing sleeve 42Y while conveying the two-component developer from the near side to the far side in the direction perpendicular to the drawing sheet. To do. The two-component developer conveyed to the vicinity of the end of the first supply unit by the first conveyance screw 43Y enters the second supply unit through an opening (not shown) provided in the partition wall 47Y. In the second supply section, the second transport screw 44Y is driven to rotate by a driving means (not shown), and transports the two-component developer sent from the first supply section in the direction opposite to that of the first transport screw 43Y. . The two-component developer transported to the vicinity of the end of the second supply unit by the second transport screw 44Y returns to the first supply unit through the other opening (not shown) provided in the partition wall 47Y. .

  A toner concentration sensor (hereinafter referred to as a T sensor) 46Y including a magnetic permeability sensor is provided on the bottom wall near the center of the second supply unit, and has a value corresponding to the magnetic permeability of the two-component developer passing therethrough. Output voltage. Since the magnetic permeability of the two-component developer has a certain degree of correlation with the toner density, the T sensor 66Y outputs a voltage having a value corresponding to the Y toner density. This output voltage value is sent to a control unit (not shown). This control unit includes a RAM, in which Y Vtref, which is a target value of the output voltage from the T sensor 46Y, is stored. In addition, data of M Vtref, C Vtref, and K Vtref, which are target values of output voltage from a T sensor (not shown) mounted in another developing device, is also stored. The Y Vtref is used for driving control of a Y toner conveying device (not shown). Specifically, the control unit drives and controls a Y toner conveying device (not shown) so that the value of the output voltage from the T sensor 46Y approaches the V Vref for Y to replenish Y toner in the second supply unit 49Y. Let By this replenishment, the Y toner concentration of the two-component developer in the developing device 40Y is maintained within a predetermined range. Similar toner replenishment control is performed for the developing devices of other process units.

  The Y toner image formed on the Y photoconductor 2Y is transferred onto a recording sheet conveyed to a paper conveyance belt described later. The surface of the photoreceptor 2Y after the transfer is neutralized by a static eliminator (not shown) after the transfer residual toner is cleaned by the drum cleaning device 48Y. Then, it is uniformly charged by the charger 30Y and prepared for the next image formation. The same applies to other process units. Each process unit is attachable to and detachable from the printer body, and is replaced when the service life is reached.

  In FIG. 1 described above, the transfer unit 11 serving as transfer means includes an endless paper transport belt 12, a driving roller 13, a stretching roller 14, four transfer bias rollers 17Y, M, C, and K. Yes. The paper conveying belt 12 which is a surface endless moving body is endlessly moved counterclockwise in the figure by a driving roller 13 which is rotated by a driving system (not shown) while being tensioned by a driving roller 13 and stretching rollers 14 and 15. .

  A transfer bias is applied to each of the four transfer bias rollers 17Y, 17M, 17C, and 17K from a power source (not shown). Then, the paper conveying belt 12 is pressed from the back surface thereof toward the photoreceptors 2Y, 2M, 2C, and 2K to form transfer nips. At each transfer nip, a transfer electric field is formed between the photoconductor and the transfer bias roller due to the influence of the transfer bias. The above-described Y toner image formed on the Y photoconductor 2Y is transferred onto the recording paper P conveyed on the paper conveying belt 12 due to the influence of the transfer electric field and nip pressure. On the Y toner image, the M, C, and K toner images formed on the photoreceptors 2M, 2C, and 2K are sequentially superimposed and transferred. By such superposition transfer, a full-color toner image combined with the white color of the paper is formed on the recording paper P, which is a recording member conveyed on the paper conveying belt 12.

  Below the transfer unit 11, three paper feed cassettes 20 for storing a plurality of recording papers P are arranged in multiple stages, and each cassette is provided with a paper feed roller on the top recording paper P. Is pressed. When the paper feed roller is driven to rotate at a predetermined timing, the uppermost recording paper P is fed to the paper transport path.

  The recording paper P fed from the paper feed cassette 20 to the paper transport path is sandwiched between the rollers of the registration roller pair 19. The registration roller pair 19 sends out the recording paper P sandwiched between the rollers at a timing at which toner images can be superimposed at each transfer nip. As a result, the toner image is superimposed and transferred onto the recording paper P at each transfer nip. The recording paper P on which the full color image is formed is sent to the fixing unit 21.

  The fixing unit 21 forms a fixing nip with a heating roller 21a having a heat source such as a halogen lamp inside and a pressure roller 21b pressed against the heating roller 21a. A full color image is fixed on the surface of the recording paper P while being sandwiched in the fixing nip. The recording sheet P that has passed through the fixing unit 21 is discharged out of the apparatus through a pair of discharge rollers (not shown).

  FIG. 3A is a longitudinal sectional view showing a Y process unit set in the printer and its peripheral configuration, and FIG. 3B is a view for Y being removed from the printer. It is a longitudinal cross-sectional view which shows a process unit with the surrounding structure. In the left and right directions of these drawings, the left side corresponds to the front side of the printer, and the right side corresponds to the rear side of the printer. As shown in FIG. 3A, the process unit 1Y set in the printer is located between a face plate 71 disposed near the front end of the printer main body and a rear plate 70 of the printer main body. As shown in FIG. 3B, a center hole penetrating from one end side to the other end side in the axial direction is formed at the center of the circle of the cylindrical photoconductor 2Y. The rear side plate 70 rotatably supports the photosensitive shaft 102 as a driven rotation shaft by a bearing (not shown). As shown in FIG. 3A, when the process unit 1Y is set in the printer, the photosensitive member shaft 102 supported by the rear plate 70 is connected to the central hole of the photosensitive member 2Y. Inserted. The cross-sectional shape of the center hole is a non-circular shape such as a D-shape or an oval shape, and the cross-sectional shape of the photoconductor shaft 102 is also similar. As a result, the rotational driving force of the photosensitive member shaft 102 is transmitted to the photosensitive member 2Y without the photosensitive member shaft 102 inserted into the central hole idling in the hole.

  Since the above-described photoconductor shaft 102 passes through the rear plate 70 of the printer main body, the rear end portion is located further on the rear side of the rear plate 70. A drive motor 100 serving as a drive source is fixed to a rear surface plate 70 of the printer body opposite to the face plate 71 via a bracket 80. The photosensitive member shaft 102 and the drive shaft 101 that is the driving rotation shaft of the drive motor 100 are aligned in the axial direction and are connected by a constant velocity joint 110.

  The drive motor 100 is a so-called direct motor that transmits a rotational driving force to the photoreceptor 2Y without using a gear or the like. By connecting the driving force between the driving shaft 101 and the photosensitive member shaft 102 without using a gear, it is possible to avoid fluctuations in the speed of the photosensitive member due to gear eccentricity and tooth pitch unevenness.

  When the process unit 1Y is removed from the printer, the movable face plate 71 is retracted from the position facing the rear side plate 70. Then, the process unit 1Y is pulled out from the rear side of the printer toward the front side. The photoreceptor 2Y is held by a frame 90 (not shown in FIG. 3B) of the process unit 1Y.

Next, a characteristic configuration of the printer according to the present embodiment will be described.
FIG. 4 is a cross-sectional view showing the constant velocity joint 110 and the surrounding configuration. In the drawing, the left side of the rear plate 70 is a unit side in which a process unit (not shown) is accommodated, and the right side is a drive transmission side in which the drive motor 100 and the like are accommodated. A bracket 80 is fixed to the surface of the rear plate 70 on the drive transmission side, and the drive motor 100 is fixed to the back surface of the bracket 80. A constant velocity joint 110 is accommodated in the bracket 80.

  The bracket 80 is a sheet metal formed by bending such as press working. And it has the two positioning pins 81 and 82 inserted in the two positioning holes 74 and 75 of the rear side board 70, respectively, and positioning the bracket 80 on the rear side board 70. As shown in FIG. Moreover, it has the fixing | fixed part 83 for fixing to the back side board 70 with a screw. The fixing portion 83 is provided with a screw hole (not shown) for fixing the bracket 80 to the rear plate 70 with screws.

  The drive motor 100 fixed to the back surface of the bracket 80 is in a state where the motor main body is positioned outside the bracket 80 by passing the drive shaft 101 as the driving rotation shaft through a round hole formed in the back surface of the bracket 80. Thus, the distal end side of the drive shaft 101 is positioned inside the bracket 80.

  The photoreceptor shaft 102 as a driven rotating shaft passes through the rear plate 70 while being press-fitted into a bearing 73 fixed to the rear plate 70. A fixing ring 103 having a diameter larger than that of the photosensitive member shaft 102 is fitted in a predetermined position in the axial direction of the photosensitive member shaft 102, and the fixing ring 103 abuts against a side surface of the bearing 73 on the unit side. The photosensitive member shaft 102 is positioned in the axial direction with respect to.

  The constant velocity joint 110 connects the drive shaft 101 and the photosensitive member shaft 102 that are aligned in the axial direction inside the bracket 80. As described above, the bracket 80 is formed by bending a sheet metal, and variation in the bending angle is likely to occur during the processing. Therefore, it is difficult to accurately position the drive motor 100 with respect to the rear plate 70. Then, the drive shaft 101 of the drive motor 100 tends to be inclined with respect to the photosensitive member shaft 102. In this printer, even if the skew of the drive shaft 101 occurs in this way, the drive shaft 101 and the photosensitive member shaft 102 are connected to each other by the constant velocity joint 110 so that the drive shaft 101 is driven to rotate relative to the photosensitive member shaft 102. It is possible to transmit force at a constant speed.

  The constant velocity joint 110 includes a female side joint 120 that is a first rotating body and a male side joint 150 that is a second rotating body. A photosensitive shaft 102 is connected to the left end of the female joint 120 in the axial direction in the drawing. A drive shaft 101 of the drive motor 100 is connected to the right end of the male joint 150 in the axial direction of the drawing.

  The female side joint 120 includes a cylindrical cup portion 121 into which the male side joint 150 is inserted from an opening provided on one end side in the axial direction. As shown in the cross section of FIG. 5, the cup 121 includes an outer ring 122, an inner ring 123 inside the outer ring 122, an annular space 124 formed by a gap therebetween, and three inner circumferential surfaces of the outer ring 122. It has an outer groove 125 and three inner grooves 126 provided on the outer peripheral surface of the inner ring 123. As shown in FIG. 4, the other end side is closed while opening one end side in the axial direction in the annular space 124, and the male side joint 150 is inserted from the opening.

  As shown in FIG. 5, the three outer grooves 125 provided on the inner circumferential surface of the outer ring 122 extend in the axial direction of the outer ring 122 and are arranged in a circular direction with a phase difference of 120 °. Is formed. The three inner grooves 126 provided on the outer peripheral surface of the inner ring 123 are also formed so as to be aligned in the circular direction with a phase difference of 120 [°] from each other while extending in the axial direction of the inner ring 123. The outer groove 125 and the inner groove 126 face each other through the annular space 124.

  The male joint 150 as the second rotating body has a cylindrical spherical body holding portion on the tip side. As shown in the cross section of FIG. 6, the spherical body holding portion 151 has three through holes 151a provided in a cylindrical peripheral wall so as to be aligned along the circumferential direction with a phase difference of 120 °. A ball 152 as a sphere is rotatably held in each through hole 151a.

  In FIG. 4 described above, the cylindrical sphere holding portion 151 of the male side joint 150 is inserted into the annular space 124 in the cup portion 121 of the female side joint 120. In this state, as shown in FIG. 7, the three balls 152 held by the sphere holding portion 151 of the male joint are respectively connected to the outer groove provided on the inner peripheral surface of the outer ring 122 of the female joint, It is sandwiched between inner grooves provided on the outer peripheral surface of 123 and movement in the normal direction is prevented. However, since the outer groove and the inner groove each extend in the axial direction, the movement of the ball 152 in the axial direction is allowed.

  As shown in FIG. 8, the cylindrical sphere holding portion 151 of the male side joint is inserted into the annular space 124 of the cup portion of the female side joint, and three balls 152 held by itself are shown in FIG. As described above, the outer and inner grooves are engaged in the annular space 124. When rotating with the drive shaft 101 of the drive motor 100 shown in FIG. 4, the rotational driving force is transmitted to the female joint 120 at a constant speed via the three balls 152. As a result, the photosensitive member shaft 102 and, consequently, the photosensitive member (not shown) rotate at a constant speed.

  In addition, although the example which provided the groove | channel for engaging the ball | bowl 125 to both the inner peripheral surface of the outer ring | wheel 122 and the outer peripheral surface of the inner ring | wheel 123 was demonstrated, you may form a groove | channel only in any one.

  7 and 8, the outer ring 122 of the cup portion 121 of the female joint 120 has a two-layer structure including an innermost layer 122a constituting the inner peripheral surface and an outer metal layer 122b. The innermost layer 122a is made of a resin material. More specifically, it is made of a synthetic resin that can be injection-molded, and may be either a thermoplastic resin or a thermosetting resin as long as injection molding is possible. Synthetic resins that can be injection-molded include crystalline resins and non-crystalline resins. Any resin may be used, but it is preferable to use a crystalline resin because the amorphous resin has low toughness and abrupt destruction occurs when a torque exceeding an allowable amount is applied. Moreover, it is desirable to use one having relatively high lubrication characteristics. Such synthetic resins include polyacetal (POM), nylon, injection moldable fluororesins (eg, PFA, FEP, ETFE, etc.), injection moldable polyimide, polyphenylene sulfide (PPS), wholly aromatic polyester, polyether ether. Examples thereof include ketone (PEEK) and polyamideimide. These synthetic resins may be used alone or may be used as a polymer alloy in which two or more kinds are mixed. Moreover, even if it is a synthetic resin other than these and resin with a comparatively low lubrication characteristic, if it is set as the polymer alloy which mix | blended the synthetic resin mentioned above, it can be used.

  The most suitable synthetic resin for the innermost layer 122a is POM, nylon, PPS, or PEEK. Nylon is nylon 6, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, nylon 46, semi-aromatic nylon having an aromatic ring in the molecular chain, or the like. Among these, POM, nylon, and PPS are excellent in heat resistance and lubricity, and are relatively inexpensive. Therefore, the constant velocity joint 110 having excellent cost performance can be realized. Moreover, PEEK is excellent in mechanical strength and lubricity even if it does not contain a reinforcing material or a lubricant, so that a high-performance constant velocity joint 110 can be realized.

  The metal layer 122b of the outer ring 122 is made of a metal such as stainless steel, steel, an aluminum alloy, or a copper alloy, and plays a role of increasing the rigidity of the outer ring 122 in the normal direction. In the constant velocity joint 110 having such a configuration, the inner peripheral surface of the outer ring 122 is formed of a resin material, so that the weight of the female side joint 120 is larger than that of the conventional configuration in which the entire outer ring 122 is formed of a metal material. Can be reduced. Further, since the inner peripheral surface of the outer ring 122 is made of a resin material, the female side joint 120 and the male side joint 150 are made of a metal material while smoothly rotating without filling the annular space 124 with grease. The operation sound can be reduced as compared with the conventional configuration. Furthermore, the outer ring 122 has a two-layer structure, and a metal layer 122b made of a highly rigid metal material is provided on the outer side of the innermost layer 122a constituting the inner peripheral surface of the outer ring 122. It is possible to suppress the bending of the outer ring 122 in the normal direction and maintain the constant speed of the rotational driving force. As a result, the constant velocity joint 110 in the printer can be reduced in weight, the operation sound at the time of torque transmission can be reduced, and grease filling can be made unnecessary. As a result, noise and grease contamination are no longer restricted, making it possible to apply to office machines, audio equipment, medical equipment, household appliances, food manufacturing equipment, etc., which were difficult in the past. it can.

  If the usage environment can tolerate grease contamination, a solid lubricant or lubricating oil can be added to the resin material to improve the lubrication characteristics. Examples of the solid lubricant include PTFE, graphite, molybdenum disulfide and the like. Moreover, glass fiber, carbon fiber, and various mineral fibers (whiskers) may be added to the resin material to increase the strength, or may be used in combination with a solid lubricant or the like. Further, the constant velocity joint 110 for transmitting the rotational driving force to the Y photoconductor has been described. However, the M, C, and K photoconductors also transmit the rotational driving force through the same constant velocity joint. It has become. Moreover, although the example of the female side joint 120 which made the cup part 121 the two-layer structure was demonstrated, even if it is a structure of 3 layers or more, while forming an innermost layer with a resin material, at least one layer other than that is a metal material With this configuration, it is possible to achieve the same effects as the two-layer structure. However, since the two-layer structure is the simplest structure in the multilayer structure, the cost can be reduced as compared with the structure having three or more layers.

  As the balls 152, bearing steel, stainless steel balls, ceramic balls, balls made of synthetic resin, or the like can be used. Of these, stainless steel balls are suitable because they are free from rusting and are inexpensive.

  As shown in FIG. 8, the cup portion 121 of the female joint 120 is formed by integrally molding the innermost layer 122a and the inner ring 123 with the same resin material inside the cylindrical metal body constituting the outermost metal layer 122b. A cup base that has been fitted is used. In such a configuration, the metal layer 122b and the innermost layer 122a made of the resin material can be formed without performing a time-consuming process of centrifugally forming the innermost layer 122a made of the resin material inside the cylindrical metal body constituting the metal layer 122b. Can be formed.

  The cup base integrally formed with the innermost layer 122a and the inner ring 123 may be fixed to the metal layer 122b with an adhesive, may be fixed with screws, or may be fixed inside the metal layer 122b without using an adhesive or screws. It is also possible to just fit it into the. However, in the case of only the fitting, in order to prevent the cup base from spinning around in the metal layer 122b, the inner peripheral surface of the metal layer 122b is formed with irregularities, while the outer peripheral surface of the cup base is provided with corresponding irregularities. It is desirable to form and engage both.

  In the cylindrical metal body constituting the metal layer 122b, a shaft portion 127 extending on the central axis is integrally formed of the same metal material as that of the cylindrical metal body. The shaft portion 127 may be fixed to the cylindrical metal body as a separate body from the cylindrical metal body, but in this case, there is a risk of causing an axial misalignment due to variations in positional accuracy at the time of fixing. By integrally forming the shaft portion 127 with the cylindrical metal body, it is possible to avoid such an axial misalignment and avoid a deterioration in the constant velocity due to the axial misalignment.

  In this printer, not only the inner peripheral surface of the outer ring 122 and the inner ring 123 of the female side joint part 120 but also the male side joint part 150 is made of a resin material. The resin material suitable for the male joint 150 is the same as that suitable for the inner peripheral surface of the outer ring 122. Further weight reduction can be achieved by configuring the male side joint portion 150 with a resin material.

  In this printer, as shown in FIG. 3B, a photosensitive member 2Y that rotates about a photosensitive shaft 102 that is a driven rotating shaft is used as a latent image carrier, and the photosensitive shaft 102 is fixed by a constant velocity joint 110. It is connected. Even if the driving shaft 101 of the drive motor 100 is skewed with respect to the photosensitive member shaft 102 due to variations in the bending accuracy of the bracket (80), the rotational driving force is transmitted to the photosensitive member 2Y at a constant speed. As already mentioned, you can do this. The photoreceptor 2Y causes the photoreceptor shaft 102 to pass through and engage with a center hole formed in the axial direction. In such a configuration, the photoconductor 2Y and the process unit 1Y can be attached to and detached from the apparatus main body with the photoconductor shaft 102 fixed to the apparatus main body. Further, by positioning the photoreceptor 2Y by engagement with the photoreceptor shaft 102 and positioning the casing of the process unit 1Y, the development gap between the developing sleeve and the photoreceptor can be accurately determined.

  In addition, although the example which connected the male side joint 150 to the drive shaft 101 of the drive motor 100 was demonstrated, you may connect the female side joint 120 to the drive shaft 101 conversely.

  In FIG. 4 described above, the male joint 150 has a shaft portion 153 that protrudes in the axial direction from one end portion of the spherical body holding portion 151 in the axial direction, and the shaft portion 153 is hollow. Then, the drive shaft 101 of the drive motor 100 is press-fitted into the hollow space of the shaft portion 153, so that the male joint 150 as the second rotating body and the drive shaft 101 as the driving rotation shaft are connected in the axial direction. Has been. In such a configuration, the drive shaft 101 is press-fitted into the hollow extending in the axial direction of the shaft portion 153, so that the drive shaft 101 is inserted into a large recess provided in the spherical body holding portion 151 and pin-fixed. The relative backlash between the drive shaft 101 and the spherical body holding portion 151 is reduced, and the eccentricity of both is suppressed. As a result, it is possible to suppress image color misregistration and misalignment due to fluctuations in the photoreceptor speed caused by the eccentricity of the two.

  The shaft portion 127 integrally formed with the metal layer 122b which is the outermost layer of the outer ring 122 of the female joint 120 also has a hollow structure, and one end portion of the photosensitive member shaft 102 is inserted into the shaft portion 127, whereby the photosensitive member. The shaft 102 and the female joint 120 are connected. In the vicinity of the end portion of the photosensitive member shaft 102, a through hole penetrating in a direction orthogonal to the axial direction is provided. In addition, a through hole penetrating in a direction orthogonal to the axial direction is also provided in a part of the peripheral wall of the shaft portion 127 of the female side joint 120. Furthermore, a screw hole is provided in a portion facing the through hole through the hollow. With the photoreceptor shaft 102 inserted into the hollow of the shaft portion 127 and the through hole of the shaft portion 127 and the through hole of the photoreceptor shaft 102 being positioned in a straight line, the screw 154 is aligned with the through hole of the shaft portion 127. After being inserted into the through hole of the photosensitive member shaft 102, it is screwed into the screw hole of the shaft portion 127. As a result, the female joint 120 is fixed to the photoreceptor shaft 102. The length of the shaft portion 127 in the hollow axial direction is set to a length in which the end surface of the shaft portion 127 abuts against a bearing 73 fixed to the rear plate 70. For this reason, when the shaft portion 127 is fixed to the photosensitive member shaft 102 by the screw 154, the fixing ring 103 fixed in advance to the photosensitive member shaft 102 and the end face of the female side joint 120 fixed to the photosensitive member shaft 102 are also provided. A bearing 73 is sandwiched between the two. This prevents the photoreceptor shaft 102 from coming off from the bearing 73. As described above, the printer is configured to prevent the female shaft 120 connected to the photosensitive shaft 102 from coming off from the bearing 73 of the photosensitive shaft 102.

  The example in which the constant velocity joint 110 is provided in the drive transmission mechanism that transmits the driving force from the drive motor 100 to the photosensitive member has been described so far, but the constant velocity joint 110 may be provided in another drive transmission mechanism. For example, the constant velocity joint 110 may be provided in a drive transmission mechanism that transmits a driving force from a driving motor to a developing sleeve as a developing member. Further, for example, the constant velocity joint 110 may be provided in a drive transmission mechanism that transmits a driving force from the driving motor to the paper conveying belt 12 (more specifically, the driving roller 13) that is a surface endless moving body.

  As described above, in the constant velocity joint 110 of the printer according to the embodiment, the outer ring 122 has a two-layer structure including the resin innermost layer 122a and the metal outermost layer 122b. Cost reduction can be realized compared to the structure.

  Further, as the cup portion 121, a cup base body in which the innermost layer 122a and the inner ring 123 are integrally formed of the same resin material is fitted into a cylindrical metal body constituting the outermost metal layer 122b. Yes. In such a configuration, the metal layer 122b and the innermost layer 122a made of the resin material can be formed without performing a time-consuming process of centrifugally forming the innermost layer 122a made of the resin material inside the cylindrical metal body constituting the metal layer 122b. Can be formed.

  Also, as the cylindrical metal body constituting the metal layer 122b, a shaft part 127 extending on the central axis is integrally formed of the same metal material as the cylindrical metal body. In such a configuration, it is possible to avoid the axial misalignment when the shaft portion formed separately from the cylindrical metal body is fixed to the cylindrical metal body, and to avoid the deterioration of the constant velocity due to the axial misalignment.

  Moreover, since the spherical body holding | maintenance part 151 consists of resin materials, weight reduction can be achieved compared with what consists of metal materials.

  Further, since the resin material constituting the innermost layer 122a is a material that can be injection-molded, the above-described cup base can be easily injection-molded to form the metal layer 122b and the innermost layer 122a made of the resin material. .

  In the printer according to the embodiment, since the constant velocity joint 110 is provided in the drive transmission mechanism that transmits the driving force from the drive motor 100 to the photosensitive member, a skew occurs between the driving shaft 101 and the photosensitive member shaft 102. In this case, the photoconductor can be rotated at a constant speed to avoid image quality deterioration due to speed fluctuation of the photoconductor. In the case where the constant velocity joint 110 is provided in the drive transmission mechanism from the drive motor to the developing sleeve, development failure due to fluctuation in the rotational speed (banding) of the developing sleeve due to skew between the driving shaft and the sleeve shaft is avoided. can do. Further, when the constant velocity joint 110 is provided in the drive transmission mechanism from the drive motor to the paper conveying belt 12 (drive roller 13), image degradation due to belt speed fluctuation caused by skew between the drive shaft and the drive roller shaft. Can be avoided.

  In the printer according to the embodiment, a drive motor 100 having a drive shaft 101 as a driving rotation shaft is used as a driving source, and a photosensitive image that rotates around a photosensitive shaft 102 as a driven rotation shaft as a latent image carrier. Since the drive shaft 101 and the photosensitive member shaft 102 are connected by the constant velocity joint 110, the speed fluctuation of the photosensitive member due to the skew between the driving shaft 101 and the photosensitive member shaft 102 can be avoided.

  Further, since the photosensitive member is used in which the photosensitive member shaft 102 is penetrated and engaged with a central hole bored in the axial direction, the photosensitive member 2Y or the photosensitive member 2Y or The process unit 1Y can be attached to and detached from the apparatus main body. Further, by positioning the photoreceptor 2Y by engagement with the photoreceptor shaft 102 and positioning the casing of the process unit 1Y, the development gap between the developing sleeve and the photoreceptor can be accurately determined.

  In addition, since the drive shaft 101 is press-fitted into the male joint 150 as the second rotating body to connect both in the axial direction, the drive shaft 101 is inserted into the large recess provided in the spherical body holding portion 151 and the pin Compared to the case of fixing, it is possible to suppress image color misregistration and misregistration due to fluctuations in the photoreceptor speed caused by the eccentricity of the male joint 150 and the drive shaft 101. Note that the male joint 150 may be press-fitted into the drive shaft 101. Moreover, you may press-fit either one among the female side joint 120 and the drive shaft 101 which are 1st rotary bodies with respect to the other in the axial direction.

  In the printer according to the embodiment, the photosensitive shaft 102 is rotatably supported by the bearing 73 fixed to the apparatus main body, and the removal of the photosensitive shaft 102 from the bearing 73 is connected to the photosensitive shaft 102. Since the configuration is such that the side joint 120 prevents it, cost reduction can be achieved by not providing a dedicated member for preventing disconnection.

1 is a schematic configuration diagram illustrating a printer according to an embodiment. FIG. 3 is an enlarged configuration diagram illustrating a process unit for Y of the printer. (A) is a longitudinal sectional view showing a process unit for Y set in the printer and its peripheral configuration, and (b) is a process unit for Y being removed from the printer together with its peripheral configuration. FIG. Sectional drawing which shows the constant velocity joint of the printer, and its surrounding structure. The cross-sectional view which shows the cup part of the female side joint of an equivalent speed joint. The cross-sectional view which shows the spherical body holding | maintenance part of the male side joint of an equivalent speed joint. The cross-sectional view which shows the cup part and the spherical body holding | maintenance part inserted in this annular space. The longitudinal cross-sectional view which shows the same cup part and the same spherical body holding | maintenance part inserted in this annular space.

Explanation of symbols

2Y, M, C, K: photoconductor (latent image carrier)
10: Optical writing unit (latent image forming means)
11: Transfer unit (transfer means)
12: Paper transport belt (surface endless moving body)
42Y: Developing sleeve (developing member)
73: Bearing 100: Drive motor (drive source)
101: Drive shaft (primary rotating shaft)
102: Photoconductor axis (driven rotation axis)
110: Constant velocity joint 120: Female side joint (first rotating body)
121: Cup part 122: Outer ring 122a: Inner layer made of resin 122b: Metal layer (outermost layer)
123: Inner ring 124: Annular space 125: Outer groove (groove)
126: Inner groove (groove)
127: Shaft 150: Male side joint (second rotating body)
151: Sphere holding part 151a: Through hole 152: Ball (sphere)

Claims (11)

A cup-shaped cup portion that opens one end side in the axial direction in the annular space by the gap between the outer ring and the inner ring inside thereof, and closes the other end side, and extends in the axial direction so as to be aligned in a circular direction with each other A first rotating body having a plurality of grooves provided on at least one of the inner surface of the outer ring and the outer surface of the inner ring,
A second rotating body having a sphere holding part for holding each sphere in a plurality of through holes provided in a cylindrical peripheral wall so as to be aligned along the circumferential direction;
The spherical body holding portion is inserted into the annular space and the plurality of spherical bodies held by the spherical body holding portion are engaged with the plurality of grooves in the annular space via the plurality of the spherical bodies. A constant velocity joint that transmits the rotational driving force of one of the first rotating body and the second rotating body to the other,
The constant velocity joint, wherein the outer ring has a multilayer structure having an innermost layer made of a resin material constituting the inner peripheral surface and a metal layer made of a metal material outside the outer ring. The constant velocity joint of claim 1,
The outer ring has a two-layer structure including the innermost layer made of resin and the outermost layer made of metal. The constant velocity joint of claim 2,
A constant velocity characterized by using a cup base in which the innermost layer and the inner ring are integrally formed of the same resin material inside the cylindrical metal body constituting the outermost layer as the cup portion. Joint. In the constant velocity joint of claim 3,
A constant velocity joint using a cylindrical metal body in which a shaft portion extending on a central axis thereof is integrally formed of the same metal material as that of a cylinder. The constant velocity joint according to claim 1,
The constant velocity joint, wherein the spherical body holding portion is made of a resin material. The constant velocity joint according to claim 1,
A constant velocity joint, wherein the resin material is a material that can be injection molded. A latent image carrier that carries a latent image on a surface that moves endlessly, a latent image forming unit that forms a latent image on the surface, and a developer that is carried on the surface that moves endlessly. A developing member for developing, a transfer means for transferring a visible image on the latent image carrier obtained by development to the surface of the surface endless moving body or a recording member held by the surface, the latent image carrier, and developing In an image forming apparatus comprising: a drive transmission mechanism that transmits a driving force from a driving source to at least one of a member and a surface endless moving body;
An image forming apparatus comprising the constant velocity joint in the drive transmission mechanism. The image forming apparatus according to claim 7.
A drive motor having a driving rotation shaft is used as the driving source, and a photosensitive member that rotates about the driven rotation shaft is used as the latent image carrier, and the driving rotation shaft and the driven rotation shaft are connected at the constant velocity. An image forming apparatus connected by a joint. The image forming apparatus according to claim 8.
An image forming apparatus using the photosensitive member as a member in which the driven rotating shaft is passed through and engaged with a center hole bored in the axial direction. The image forming apparatus according to claim 8 or 9,
One of the first rotating body or the second rotating body and the driving rotating shaft of the drive motor is press-fitted in the axial direction with respect to the other, whereby both are connected in the axial direction. An image forming apparatus. The image forming apparatus according to claim 9.
The driven rotating shaft is rotatably supported by a bearing fixed to the apparatus main body, and the driven rotating shaft is prevented from coming off from the bearing by the first rotating body or the second rotating body connected to the driven rotating shaft. An image forming apparatus characterized in that it is configured as described above.

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