JP2010054701A - Drive unit and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a steep rise in device cost by securing excellent centering of axes of output shafts in a drive unit in which the output shafts of a plurality of drive motors are juxtaposed. <P>SOLUTION: A casing structure 40 is mounted with predetermined driving members inside and includes an erection plate 44, which is a component of the casing structure 40, interposed between each first driving motor 30 and a base frame 90 and positioned by partly abutting on positioning holders 50. One lateral end of the erection plate 44 includes a close fitting hole 441a fitted in a close contact state to the positioning holder 50, and the other end includes an elongate hole 441b allowing lateral movement after regulating the vertical movement of the positioning holder 50. Loose holes 441c larger in diameter than the positioning holder 50 for inserting other positioning holders 50 are provided between the close fitting hole 441a and the elongate hole 441b. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drive unit that transmits a driving force to a rotated body that is supported so as to be integrally rotatable about a predetermined rotation axis, and an image forming apparatus to which the drive unit is applied.

  Conventionally, an image forming apparatus for color printing as described in Patent Document 1 is known. This image forming apparatus includes four developing devices filled with four color toners (specifically, black toner, yellow toner, magenta toner, and cyan toner) each having a stirring member, a developing roller, and the like. And four photosensitive drums for forming a toner image on the peripheral surface by supplying toner from the developing roller of each developing device. An electrostatic latent image based on image information is formed in advance on the peripheral surface of each photosensitive drum, and a toner image is formed along the electrostatic latent image by supplying toner from each developing device.

  Four drive motors for driving the toner agitating member and developing roller of each developing device, and each photosensitive drum, and four sets of gears for transmitting the driving motor to the developing roller and the photosensitive drum. The mechanism is adopted. Each gear mechanism is sandwiched between a pair of side plates as a housing, and a drive unit is employed in which each drive motor is mounted on the outside of one side plate.

  The drive shaft of each drive motor fixed to the outside of one side plate passes through the one side plate and the other side plate, and is the base frame of the apparatus main body of the image forming apparatus (in Japanese Patent Application Laid-Open No. 2005-32083, the image forming apparatus main body casing). 26) is concentrically connected to the photosensitive drum in a state of being supported by the shaft holder penetratingly attached to 26).

By adopting such a drive unit, it is possible to improve recyclability and assemblability as compared with the case where the drive mechanism is not unitized, and contribute to positioning of the pitch between the photosensitive drums. It is explained that you can.
JP 2005-91780 A

  By the way, in the drive shaft support structure described in Patent Document 1 described above, when the drive unit is fixed to the base frame, each drive shaft protruding from the housing causes a dimensional error of each member in the housing. It is uncertain whether the shaft holder attached to the base frame is properly penetrated due to the assembly error or the like. In order to eliminate such an uncertain element, in the drive shaft support structure of Patent Document 1, a base frame with no play is provided in the base frame for the shaft holder at one end, and the other An elongated hole is provided for the shaft holder at the end, and the play of the elongated hole absorbs a dimensional error in the arrangement of the drive shaft (see paragraphs [0007] and [0008] of FIG. 11 and FIG. 11). reference).

  However, even if the shaft holder for the drive shaft at one end is used as a target, a hole with no play is provided in the shaft holder, and a slot with play at the other end is provided, so that the drive unit and the base frame However, the incompatibility between the through hole provided on one side plate of the drive unit in the previous stage and the drive shaft (specifically, the drive shaft passes through the through hole). However, the positional relationship between the drive shaft and the through hole in the side plate of the housing that is easily affected by various members such as a gear mechanism mounted on the drive unit is not eliminated. Is more of a problem. That is, if the drive shaft of the drive motor is positioned by the side plate of the drive unit, when the drive unit is attached to the base frame, the centering state between the drive shaft and the drum shaft of the photosensitive drum is properly set. The inconvenience of not being performed occurs.

  In order to eliminate such inconvenience, various members must be made highly accurate by reducing their dimensional errors and assembly errors to the limit, which raises the problem of increasing costs.

  The present invention has been made in view of the situation as described above, and suppresses an increase in device cost while ensuring good centering of the drive shafts (output shafts) of a plurality of drive motors. An object of the present invention is to provide a drive unit that can perform the above and an image forming apparatus to which the drive unit is applied.

  According to a first aspect of the present invention (drive unit), a first unit frame plate integrally disposed opposite to a base frame having a plurality of first through holes, and an interposition between the base frame and the first unit frame plate. A plurality of first drive motors arranged in parallel to the first unit frame plate through the respective first through holes to which the respective output shafts correspond, and the respective output shafts A plurality of cylindrical positioning holders that are mounted on the first drive motors in a state where the first unit motor is penetrated, and a plurality of second drive motors that are mounted on the first unit frame plate. The plate has a plurality of second through holes into which the positioning holders are fitted, and a plurality of third through holes to be closely fitted with the drive shafts of the second drive motors. And said The through hole is a close fitting hole in which one end is fitted in close contact with the outer peripheral surface of the positioning holder, and the other end extends in the direction in which the second through holes are arranged side by side. It is characterized by the fact that it is a long hole and that between both ends is a stupid hole.

  According to such a configuration, the positioning holder is mounted on each first drive motor in a state where the plurality of first and second drive motors are respectively attached to the first unit frame plate, and subsequently each second of the second unit frame plate. Each of the first and second drive motors is fitted to the first and second drive motors by fitting the through holes to the corresponding positioning holders and fitting the third through holes to the corresponding drive shafts of the second drive motors. A drive unit which is mounted on the second unit frame plate and unitized is formed.

  Next, after the output shaft of each first drive motor is fitted into each first through hole of the base frame, the first unit frame plate is fixed to the base frame, whereby the drive unit is integrated with the base frame.

  When the drive unit is mounted on the base frame, the output shaft of the first drive motor is positioned by the first through hole of the base frame, and as a result, the first drive motor is also positioned. ing. Therefore, the positioning holder mounted on the first drive motor is also positioned with respect to the output shaft. The second unit frame plate is positioned with respect to the output shaft via the positioning holder by fitting the second through hole at one end thereof in close contact with the positioning holder. Therefore, the positioning shaft and the second unit frame plate of the second drive motor inserted into the third through hole formed in the second unit frame plate in the positioning state are also located with respect to the output shaft of the first drive motor. It is in a state where it is inevitably positioned via

  With the first unit frame plate, to which the first and second drive motors are mounted, being attached to the base frame, the drive shaft of the second drive motor is securely connected to the output shaft of the first drive motor. Since they are positioned, the driving force transmission mechanisms for transmitting the driving force including gear mechanisms and the like provided on the output shaft and the driving shaft of the first and second driving motors interfere with each other. Thus, it is possible to reliably prevent the occurrence of inconveniences that make it impossible to drive smoothly.

  The second unit frame plate is provided with a close fitting hole that fits in close contact with the positioning holder at one end in a direction orthogonal to the output shaft (hereinafter referred to as the left-right direction). A long hole that restricts the movement of the positioning holder in the vertical direction and allows it to move in the horizontal direction is provided at the end of the positioning holder, and another positioning holder is inserted between the close fitting hole and the long hole. Since the idiot hole having a diameter larger than that of the positioning holder for insertion is provided, one end side of the second unit frame plate is vertically and horizontally left and right through a close fitting hole in which the positioning holder is closely fitted. While being positioned, the other end of the positioning holder can escape from the left and right and left and right through the idiot hole.

  Therefore, in the drive unit, various drive means and gear mechanisms provided in cooperation with each other on the second unit frame plate interfere with each other, thereby causing dimensional errors and assembly errors of the gear mechanism to the positioning holder. Even if the resulting extra force is applied, the two positioning holders in the center can move in the idiot hole in either the top, bottom, left or right direction, and the positioning holder on the other end can move in the left or right direction. The extra force is absorbed by this, so that the so-called mating state or hell tightening state in which the gear mechanism in the drive unit interferes with each other and does not move while maintaining the horizontal posture of the second unit frame plate is eliminated, As a result, the drive unit can function properly.

  According to a second aspect of the present invention, in the first aspect of the invention, each of the first drive motors has a boss portion through which each of the output shafts penetrates, and the other end of each of the positioning holders It is characterized by being externally fitted to each boss part.

  According to this configuration, the positioning holder is not only positioned once on the base frame via the bearing, but the other end is positioned on the output shaft via the boss of the first drive motor. The positioning holder is in a state where both ends thereof are positioned with respect to the output shaft. Therefore, the drive unit supported by the positioning holder can secure a more reliable positioning state with respect to the output shaft.

  According to a third aspect of the present invention, in the second aspect of the present invention, each of the output shafts is passed through the corresponding first through hole via a bearing, and the positioning holder is fitted on the boss portion. The end opposite to the side that is provided is externally fitted to the corresponding bearing.

  According to such a configuration, since the output shaft of each first drive motor is supported by the corresponding first through hole of the base frame via the bearing, it can rotate smoothly. Each positioning holder has one end concentrically supported by the boss portion of the first drive motor and the other end concentrically supported by the bearing, whereby both end portions are in a supported state. Therefore, a stable and reliable positioning state with respect to the output shaft is ensured.

  According to a fourth aspect of the present invention (image forming apparatus), a base frame, a plurality of photosensitive drums each having a drum shaft and carrying a toner image, and a plurality of output shafts coupled to the drum shafts are provided. A plurality of second drive motors for driving driven members other than the photosensitive drum, and a structure for attaching the plurality of first and second drive motors to the base frame, The drive unit according to any one of claims 1 to 3 is employed.

  According to this configuration, the image forming apparatus can receive the effects of the structure for rotating the photosensitive drum by applying the drive unit according to any one of claims 1 to 3. Therefore, the drive rotation of the first drive motor is properly transmitted to the rotation of the photosensitive drum, and the drive rotation of the second drive motor is properly transmitted to the drive of the target driven member, so that proper image formation is always performed. Processing is realized.

  According to the drive unit of the present invention, a tight fitting hole is formed on one end side as a second through hole for penetrating the positioning holder provided on the second unit frame plate of the drive unit, and the other end. Various drive means provided in the drive unit by adopting a simple configuration in which a long hole is drilled on the side, and a stupid hole is drilled in a portion sandwiched between the close fitting hole and the long hole It is no longer necessary to increase the dimensional accuracy and assembly accuracy of gear mechanisms, etc., and it is possible to contribute to the reduction of component costs and assembly costs while ensuring the original functions of the drive unit. .

  According to the image forming apparatus of the present invention, the driving rotation of the first drive motor is appropriately transmitted to the rotation of the photosensitive drum, and various image processing processes can be performed while ensuring the proper image forming process. The parts cost and assembly cost of the member can be reduced.

  FIG. 1 is a partially cutaway exploded perspective view showing an embodiment of a drive unit according to the present invention, and FIG. 2 is an assembled perspective view thereof. FIG. 3 is a partially enlarged perspective view of FIG. 2 and shows a tightly fitting mounting structure in the drive unit. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1 to 4, the X direction is referred to as the left-right direction, and the Y direction is referred to as the front-rear direction. In particular, −X is referred to as the left, + X is the right, −Y is the front, and + Y is the rear.

  The drive unit 20 according to the present invention is configured such that a housing structure 40 having a plurality of first and second drive motors 30 and 39 can be attached to the base frame 90. FIG. As shown in FIG. 1, the driving force of the plurality of first drive motors 30 is applied to a pair of base frames 90 in a predetermined device (FIG. 1 shows only the rear base frame 90 of the pair of base frames 90. ) Are transmitted to a plurality of rotating members 80 disposed between them, and a driving force of a plurality of second drive motors 39 is transmitted to each of a plurality of driven members (not shown). At this time, in particular, unnecessary interference between the plurality of first drive motors 30 arranged side by side can be appropriately driven and rotated, and the output shaft 32 of the first drive motor 30 and the second This is to ensure an appropriate positioning state between the drive motor 39 and the drive shaft 391.

  The drive unit 20 includes a plurality (four in this embodiment) of first drive motors 30 each having an output shaft 32 and a plurality (eight in this embodiment) each having a drive shaft 391 in the housing structure 40. The second drive motor 39, the positioning holder 50 through which the output shaft 32 passes, the bearing 60 that supports the output shaft 32 mounted in the fitting insertion hole 91 of the base frame 90, and the rotating shaft 81 of the rotating member 80. And a coupling member 70 that is concentrically interposed between the output shaft 32 and the output shaft 32.

  Each of the rotating members 80 includes a rotating shaft 81 extending in the front-rear direction, and a rotated body 82 that is concentrically fixed to the rotating shaft 81 so as to be integrally rotatable. And the to-be-rotated body 82 exhibits the predetermined function because the to-be-rotated body 82 rotates integrally with the rotating shaft 81 by the drive of the 1st drive motor 30. A D-cut surface 811 formed by cutting out the peripheral surface for concentrically connecting to the output shaft 32 via the coupling member 70 is formed at the tip of the rotating shaft 81.

  The base frame 90 is formed of a hard synthetic resin material, and the thickness dimension is set to approximately ½ of the thickness dimension of the bearing 60 in the hole center direction. The base frame 90 has a fitting insertion hole (first through hole) 91 for fitting the bearing 60 therein. The diameter of the fitting hole 91 is set slightly smaller than the outer diameter of the bearing 60. The bearing 60 is press-fitted into the insertion hole 91 so that the front half of the bearing 60 is fixed to the insertion hole 91 while leaving the rear half. The front end of the positioning holder 50 is press-fitted into a portion protruding toward the rear of the bearing 60.

  Each of the first drive motors 30 includes a cylindrical motor body 31 having a rotor inside, and an output shaft 32 that projects concentrically from the front end surface of the motor body 31 toward the front. A boss 311 is concentrically provided on the front end surface of the motor body 31. Further, a plurality of (four in the example shown in FIG. 1) projecting pieces 312 are provided at the front end of the motor body 31 so as to project outward in the radial direction at an equal pitch in the circumferential direction. These projecting pieces 312 are provided with mounting holes 313 penetrating in the front-rear direction. Bolts B are inserted into the mounting holes 313 and screwed to a rear plate 45 described later of the housing structure 40. As shown in FIG. 2, each first drive motor 30 is fixed to the housing structure 40 by being screwed into the bolt hole 452.

  The mounting hole 313 is set to have a diameter slightly larger than the diameter of the bolt B, so that there is play when the bolt B is inserted into the mounting hole 313. By doing so, it is possible to absorb an error in the screwing position of the bolt hole 452 provided in the rear plate 45 described later of the housing structure 40.

  The output shaft 32 is set so that the protruding amount from the boss 311 is slightly longer than the longitudinal dimension of the housing structure 40. Therefore, when the first drive motor 30 is mounted on the housing structure 40, the output shaft 32 is connected to the boss support hole (third through hole) of the rear plate 45 of the housing structure 40 as shown in FIGS. ) And 451 and the fitting insertion hole 91 of the base frame 90, and a state of protruding toward the front of the base frame 90. A D-cut surface 321 formed by cutting the peripheral surface is formed at the front end of the output shaft 32.

  In the state in which each first drive motor 30 is mounted on the housing structure 40, the tip of each output shaft 32 and the tip of each rotary shaft 81 projecting from the rotated body 82 of each rotary member 80 are These are coupled to each other via a coupling member 70 having a D hole 71 having a D-shaped cross section. As a result, the drive rotation of each output shaft 32 is transmitted to each corresponding rotation shaft 81 via each coupling member 70.

  The housing structure 40 is interposed between each first drive motor 30 and the base frame 90. The casing structure 40 is provided with a member having a predetermined function (for example, a motor or a gear mechanism other than the first drive motor 30), but the description thereof is omitted here. The casing structure 40 includes a plurality of cylindrical positioning holders 50 in which the output shafts 32 are penetrated.

  Such a housing structure 40 has a vertical dimension that is approximately twice the diameter of the first drive motor 30 in a front view as viewed from the −Y direction and a dimension that allows a plurality of the first drive motors 30 to be arranged side by side with a margin. The bottom plate 41 that is long in the left-right direction, the top plate 42 of the same shape that is disposed opposite to the bottom plate 41 at the top, and extends from the front edges of the bottom plate 41 and the top plate 42 in opposite directions. A pair of upper and lower flange plates 43 provided, a rear plate (first unit frame plate) 45 laid between the rear edges of the bottom plate 41 and the top plate 42, and a substantially center in the front-rear direction of the bottom plate 41 and the top plate 42 And an installation plate (second unit frame plate) 44 provided between the positions.

  On the other hand, the bottom plate 41 and the top plate 42 are respectively provided with protrusions 46 at substantially central positions in the front-rear direction. These protrusions 46 are provided over the entire length in the left-right direction of the bottom plate 41 and the top plate 42 in a state of protruding by a predetermined width dimension in directions corresponding to each other. The upper and lower ridges 46 are screwed with a plurality of screw holes 461 at an equal pitch. On the other hand, the installation plate 44 is provided with drive shaft insertion holes 442 at positions corresponding to the respective screw holes 461. Then, with the installation plate 44 pressed against the pair of upper and lower ridges 46 from the front, the installation plate 44 is screwed into the screw hole 461 through the drive shaft insertion hole 442 and fastened, whereby the installation plate 44 is fixed to the bottom plate 41. And between the top plate 42.

  A holder insertion hole (second through hole) 441 for supporting the center portion in the front-rear direction of the positioning holder 50 or inserting the positioning holder 50 is formed in the center portion of the installation plate 44. In addition, the rear plate 45 is provided with a boss support hole 451 for supporting a boss 311 protruding forward from the motor body 31 of the first drive motor 30. The rear plate 45 is screwed with a bolt hole 452 at a position facing the mounting hole 313 formed in the protruding piece 312 of the first drive motor 30. The first drive motor 30 is fixed to the rear plate 45 by the bolt B inserted through the mounting hole 313 being screwed into the bolt hole 452 and fastened.

  In addition, a predetermined number of insertion holes 431 are formed at appropriate positions of the flange plate 43, and screw holes 92 are respectively screwed into the base frame 90 at positions corresponding to the insertion holes 431. The housing structure 40 is fixed to the base frame 90 by screwing the screws 47 into the screw holes 92 through the insertion holes 431 and fastening them. The screwing position of the screw hole 92 is set to a position facing the insertion hole 431 in a state where the hole center of the fitting insertion hole 91 and the hole center of the holder insertion hole 441 face each other in the front-rear direction.

  In the present embodiment, the second drive motor 39 is point-symmetric with respect to one first drive motor 30 on the rear surface side of the rear plate 45 (that is, outside the housing structure 40). Two units are provided with screws at the upper left position and the lower right position, respectively. Since there are four first drive motors 30 provided in the housing structure 40, a total of eight second drive motors 39 are employed. From each second drive motor 39, a forward drive shaft 391 penetrating the rear plate 45 is provided.

  As shown in FIG. 3, the second drive motor 39 is arranged in front of the base frame 90 via a predetermined gear mechanism 392 provided in a space between the installation plate 44 and the rear plate 45 in the housing structure 40. This is for driving a not-shown driven device provided in the apparatus. Accordingly, the gear mechanism 392 is interposed between the drive shaft 391 and the second drive motor 39, but the gear mechanism 392 is not shown in FIGS. 1 to 3 to prevent the illustration from being complicated. In this case, the gear mechanism 392 is not present.

  On the other hand, the base frame 90 is provided with a plurality of drive shaft insertion holes 443 through which the drive shafts 391 are inserted at positions corresponding to the drive shafts 391. In the present embodiment, bearings 444 are fitted into the drive shaft insertion holes 443, respectively. Each drive shaft 391 is inserted through the corresponding drive shaft insertion hole 443 via the corresponding bearing 444, and thereby protrudes toward the front of the base frame 90.

  In addition, the diameter dimension of the drive shaft insertion hole 443 may be set so that the drive shaft 391 is inserted into the drive shaft insertion hole 443 in a sliding contact state without using the bearing 444 in particular.

  The drive shaft 391 is connected to a driven member other than the rotating member 80 via a coupling (not shown) attached to the front end of the drive shaft 391 so as to drive the driven member.

  In the present invention, one of the plurality of holder insertion holes 441 formed in the installation plate 44 (the right end in this embodiment) is tightly fitted to the positioning holder 50 in a close contact state. The other end (left end in this embodiment) is a long hole 441b elongated in the left-right direction, and the remaining holder insertion hole 441 is a stupid hole 441c into which the positioning holder 50 can be loosely fitted. Has been.

  Each positioning holder 50 includes a cylindrical holder body 51 that is slightly tapered toward the front, and a square flange 52 that is formed on the rear end side of the cylindrical holder body 51. As shown in FIG. 4, the cylindrical holder main body 51 is formed with a central equal circular portion 513 at a position corresponding to the close fitting hole 441a formed in the installation plate 44 of the housing structure 40 on the outer peripheral surface thereof. In addition, a rear equal circular portion 514 is formed at a position corresponding to the boss 311 of the first drive motor 30 on the inner peripheral surface of the cylindrical holder body 51.

  The center equal circular portion 513 is set to have a front-rear width dimension equal to a thickness dimension of the installation plate 44, a constant outer diameter dimension, and slightly smaller than an inner diameter dimension of the close fitting hole 441a. The rear equal circular portion 514 has a front-rear width dimension obtained by subtracting a thickness dimension of the rear plate 45 from a thickness dimension before and after the boss 311 and has a constant inner diameter dimension and slightly larger than the outer diameter dimension of the boss 311. Is set.

  In this way, by making the outer diameter dimension of the center equal circular portion 513 constant in the front-rear direction, the inner peripheral surface of the close fitting hole 441a in the holder insertion hole 441 of the installation plate 44 is center-contacted by surface contact. Since it is fitted on the circular portion 513, the support state of the construction plate 44 with respect to the central equal circular portion 513 is stabilized. The same applies to the rear equal circular portion 514, and the support state of the boss 311 of the first drive motor 30 by the rear equal circular portion 514 is stabilized. That is, the right end of the plurality of positioning holders 50 is reliably positioned by the close fitting hole 441 a in the installation plate 44.

  On the other hand, for the leftmost one of the positioning holders 50, the counterpart holder insertion hole 441 to be externally fitted is a long hole 441 b that is long in the circumferential direction. Although positioning in the vertical direction is performed, movement in the horizontal direction is possible. Further, with respect to the two other than both ends of the positioning holder 50, the other holder insertion hole 441 to be externally fitted is an idiot hole 441 c having a diameter larger than that of the cylindrical holder body 51. Can move in all directions.

  As described above, three types of the holder insertion hole 441, that is, the close fitting hole 441a at the right end, the long hole 441b at the left end, and the idiot hole 441c at the center, are adopted when the drive unit 20 is attached to the base frame 90. This is to prevent the tightening state.

  In the present embodiment, the flange 52 has a square shape when viewed from the -Y direction, and is set to extend in a direction orthogonal to the direction in which the cylindrical center of the cylindrical holder body 51 extends. At an appropriate position on the rear surface of the flange 52, an anti-rotation protrusion 521 protrudes rearward, while an anti-rotation hole 453 corresponding to the anti-rotation protrusion 521 is formed in the rear plate 45. When the rotation preventing projection 521 is fitted into the rotation preventing hole 453, the positioning holder 50 is prevented from rotating around the cylinder center.

  Each positioning holder 50 has a distance between the rear surface of the flange 52 and the front surface of the cylindrical holder body 51 such that the rear surface of the base frame 90 and the housing structure 40 are in a state where the housing structure 40 is fixed to the base frame 90. The length is set to be equal to the distance from the front surface of the rear plate 45 (that is, the inner dimension between the two).

  Further, the front circular hole 511 at the front end of the cylindrical holder body 51 has a hole diameter set to be the same as or slightly larger than the outer diameter of the bearing 60, and the rear circular hole 512 at the rear end has a hole diameter. Is set to be the same as or slightly larger than the outer diameter of the boss 311 of the first drive motor 30.

  Accordingly, in the state where the front half of the bearing 60 is press-fitted into the fitting insertion hole 91 of the base frame 90, the front circular hole 511 of the cylindrical holder body 51 inserted from the rear into the holder insertion hole 441 of the installation plate 44 is inserted into the bearing 60. In this state, the housing structure 40 is attached to the base frame 90 with screws 47, and the output shaft 32 of the first drive motor 30 is passed through the bearing 60. The boss 311 is fitted into the rear circular hole 512 of the cylindrical holder main body 51, and then the motor main body 31 is fixed to the rear plate 45 with the bolt B, and the output shaft 32 is connected to the rotary shaft of the rotary member 80 via the coupling member 70. 81, the first drive motor 30 is attached to the base frame 90 after being assembled as a figure drive unit. .

  As described above in detail, according to the drive unit 20 of the present invention, each positioning holder that is disposed in the housing structure 40 and through which the output shafts 32 of the plurality of first drive motors 30 are respectively penetrated. 50, since one end is externally fitted to the bearing 60 and the output shaft 32 is internally fitted to the other end, it is positioned with high accuracy with respect to the output shaft 32. Yes. Therefore, since the housing structure 40 including the plurality of positioning holders 50 is positioned with high accuracy with respect to the output shaft 32 via the positioning holder 50 (that is, the output shaft 32 has the housing structure 40). Therefore, the positional relationship of the various members housed in the drive unit 40 with respect to the output shaft 32 is always appropriate. can do.

  The casing structure 40 is provided with a predetermined drive member, is interposed between each first drive motor 30 and the base frame 90, and is positioned by partly contacting the positioning holder 50. An installation plate (second unit frame plate) 44 for forming the housing structure 40 of the drive unit 20 is provided.

  The installation plate 44 is provided with a tight fitting hole 441a that fits in close contact with the positioning holder 50 at one end in the left-right direction (the right end in the example shown in FIG. 1). A long hole 441b that restricts the movement of the positioning holder 50 in the vertical direction and allows it to move in the horizontal direction is provided at the end (left end in the example shown in FIG. 1). Between the hole 441b, an idiot hole 441c having a diameter larger than that of the positioning holder 50 through which the other positioning holder 50 is inserted is provided, so that the right side of the construction plate 44 is the rightmost end positioning holder 50. The positioning holder 50 can be displaced in the left-right direction through the long hole 441b, and the other positioning holders 50 can be It has become possible to escape to the up, down, left and right by a fool hole 441c.

  Therefore, in the housing structure 40 of the drive unit 20, various drive means and gear mechanisms that are provided in cooperation with the installation plate 44 interfere with each other, thereby causing the positioning holder 50 to have a dimensional error such as a gear mechanism. Even if an unscheduled extra force due to an assembly error is applied, the two positioning holders 50 at the center move in the idiot hole 441c in either the top, bottom, left or right direction, and the leftmost end positioning The extra force is absorbed by the movement of the holder 50 in the left-right direction, thereby eliminating the so-called hell tightening state in which the gear mechanisms and the like in the housing structure 40 interfere with each other and do not move. 20 can function properly.

  The holder insertion hole 441 provided in the installation plate 44 is thus provided with a tight fitting hole 441a on one end side and a long hole 441b on the other end side. Further, the tight fitting hole 441a By adopting a simple configuration in which the idiot hole 441c is formed in the portion sandwiched between the holes 441b, dimensional accuracy and assembly accuracy of various driving means and gear mechanisms provided in the housing structure 40 are unnecessary. It is not necessary to achieve high accuracy at all, and accordingly, the original function of the drive unit 20 can be secured while contributing to a reduction in component costs and assembly costs.

  In the present embodiment, the first drive motor 30 has a boss 311 through which the output shaft 32 passes, and the positioning holder 50 is externally fitted to the output shaft 32 via the boss 311, so that the result As a result, the positioning holder 50 is not in direct contact with the rotating output shaft 32, and the output shaft 32 can be smoothly rotated.

  Incidentally, the reason why the close fitting hole 441a, the long hole 441b, and the idiot hole 441c are provided in the erection plate 44 without being provided in the base frame 90 or the rear plate 45 of the housing structure 40 is as follows. That is, in the housing structure 40, the output shaft 32 of the first drive motor 30 is passed through the positioning holder 50 in the front-rear direction, and the housing is maintained while maintaining a relative positional relationship with the penetrated output shaft 32. Various drive means and gear mechanisms are provided in the structure 40, and these gear mechanisms and the like are often mounted on a construction plate 44 provided at an intermediate position in the front-rear direction of the housing structure 40. Therefore, the influence of the assembly error of the gear mechanism or the like is often exerted on the output shaft 32 via the installation plate 44. Accordingly, the driving means, the gear mechanism, and the like are supported, but in order to prevent the influence from reaching the output shaft 32 via the positioning holder 50, the close fitting hole 441a as the holder insertion hole 441 provided in the installation plate 44 is long. Three types of holes 441b and idiot holes 441c are employed.

  The drive unit 20 configured as described above is applied to the image forming apparatus 10 according to the present invention. Hereinafter, the image forming apparatus 10 will be described with reference to FIGS. 5 and 6. FIG. 5 is a front sectional view illustrating an embodiment of the outline of the internal structure of the image forming apparatus 10 to which the drive unit 20 according to this embodiment is applied. FIG. 6 is a partially cutaway perspective view of the external appearance, and is shown for easy understanding of the installation position of the drive unit 20 according to the present invention in the image forming apparatus 10. In addition, the direction display by X and Y in FIG. 5 and FIG. 6 is the same as that of FIG. 1 (-X: leftward, + X: rightward, -Y: forward, + Y: backward).

  First, as shown in FIG. 1, an image forming apparatus 10 according to the present embodiment is used as a copying machine for color printing, and includes an apparatus main body 11 having a box shape and an upper portion of the apparatus main body 11. And a basic configuration provided with an image reading section 16 for reading a document image.

  The apparatus main body 11 includes an image forming unit 12 that forms an image based on image information of a document read by the image reading unit 16, and a fixing process for an image formed by the image forming unit 12 and transferred to the paper P. A fixing unit 13 for performing the above and a sheet storage unit 14 for storing a transfer sheet are provided.

  The image reading unit 16 includes a document presser cover 161 provided on the upper surface of the apparatus main body 11 so as to be openable and closable, and an optical unit disposed in opposition to the document presser cover 161 via a contact glass 163 in the upper housing of the apparatus main body 11. System unit 162. The contact glass 163 is dimensioned to a plane shape slightly smaller than the document pressing cover 161 in order to read the document surface of the placed document. The document pressing cover 161 opens and closes by rotating forward and backward about a predetermined axis provided on one side of the upper surface of the casing of the image reading unit 16.

  An operation panel 17 (see FIG. 2) is provided at an appropriate position of the image reading unit 16 for inputting processing conditions relating to document reading, copying processing, and the like. As shown in FIG. 2, the operation panel 17 is provided with a power switch 171, a numeric keypad 172, a start button 173, an LCD (Liquid crystal display) 174, a mode switching key (not shown), and the like.

  The optical system unit 162 includes a light source (not shown), a plurality of mirrors, a lens unit, and a CCD (charge coupled device). The light from the light source is reflected by the original surface, and the reflected light is input to the CCD as original information through the mirror and the lens unit. Document information as an analog amount input to the CCD is converted into a digital signal and stored in a predetermined storage device.

  The image forming unit 12 forms a toner image on a sheet fed from the sheet storage unit 14, and in this embodiment, the image forming unit 12 causes the image forming unit 12 to flow downstream from the upstream side (the left side of the paper surface in FIG. 1). A magenta unit 12M, a cyan unit 12C, a yellow unit 12Y, and a black unit 12K are sequentially arranged toward the side.

  Each unit 12M, 12C, 12Y, 12K is provided with a photosensitive drum (image carrier) 121 and a developing device 122, respectively. Each photosensitive drum 121 receives supply of toner from a corresponding developing device 122 while rotating counterclockwise in FIG. Each developing device 122 includes an intermediate hopper from a toner container 15 disposed so as to correspond to the developing device 122 on the front side (front side of the paper surface of FIG. 1) of the apparatus main body 11 and the right side surface of FIG. The toner is supplied through 19.

  In this embodiment, a toner container 15 (a magenta toner container 15M, a cyan toner container 15C, and a yellow toner container 15Y) for supplying each color toner to the developing devices 122 of the magenta to yellow units 12M, 12C, and 12Y. ) Is an upper front corner portion of the apparatus main body 11 and is detachably provided at a position in front of the optical system unit 162. On the other hand, the toner container 15 (black toner container 15K) for supplying black toner to the developing device 122 of the black unit 12K is long in the front-rear direction and has a larger capacity than other containers. ing. The black toner container 15K is detachably provided in an empty space on the right side of the optical system unit 162 at the upper part of the apparatus main body 11.

  The intermediate hopper 19 interposed between the toner container 15 and the developing device 122 is provided corresponding to a magenta developing device, a cyan developing device, a yellow developing device, and a black developing device. ing.

  As shown in FIG. 1, each of the intermediate hoppers 19 has a parallel pitch based on a supply port for supplying toner to each developing device 122 as the reference pitch of the developing devices 122. . The intermediate hopper 19 for magenta toner to yellow toner is set to the same size. On the other hand, the black intermediate hopper 19 is set to be long in the left-right direction so as to correspond to the black toner container 15K mounted on the upper right end in the apparatus main body 11.

  The intermediate hopper 19 is provided with a toner receiving port on the right side of the top plate. On the other hand, on the bottom plate of the mounting space in which the toner container 15 is mounted, a communication opening is formed at a position corresponding to each toner receiving port, and toner is supplied to the developing device 122 through the communication opening.

  A charger 123 is provided at a position directly above each photosensitive drum 121. An exposure device 124 is provided above the charger 123 and the developing device 122. Each photosensitive drum 121 is charged uniformly by the charger 123, and laser light corresponding to each color based on the image data input by the image reading unit 16 is charged from each exposure device 124. By irradiating the circumferential surface of each photosensitive drum 121, an electrostatic latent image corresponding to each color is formed on the circumferential surface of each photosensitive drum 121. By supplying each color toner from the developing device 122 to the electrostatic latent image, a toner image is formed on the peripheral surface of the photosensitive drum 121.

  A transfer belt 125 stretched between the driving roller 125a, the driven roller 125b, the pressing roller 125c, and other necessary rollers so as to be in contact with the peripheral surface of each photosensitive drum 121 at a position below the photosensitive drum 121. Is provided. The transfer belt 125 is in contact with the driving rollers 125 a while being synchronized with the photosensitive drums 121 while being pressed against the peripheral surface of the photosensitive drums 121 by primary transfer rollers 126 provided corresponding to the photosensitive drums 121. It circulates between the driven roller 125b.

  Accordingly, when the transfer belt 125 circulates, the magenta toner image is transferred onto the surface of the transfer belt 125 by the photosensitive drum 121 of the magenta unit 12M, and then the photosensitive drum of the cyan unit 12C is placed at the same position on the transfer belt 125. The transfer of the cyan toner image by 121 is performed in the overcoating state, and then the transfer of the yellow toner image by the photosensitive drum 121 of the yellow unit 12Y to the same position of the transfer belt 125 is performed in the overcoating state. The transfer of the black toner image by the photosensitive drum 121 of the black unit 12K is performed in an overcoated state, whereby a color toner image is formed on the surface of the transfer belt 125. The color toner image formed on the surface of the transfer belt 125 is transferred to the paper P conveyed from the paper storage unit 14.

  A cleaning device 127 that removes and cleans the residual toner on the peripheral surface of the photosensitive drum 121 is provided at the left position in FIG. 1 of each photosensitive drum 121. The peripheral surface of the photosensitive drum 121 cleaned by the cleaning device 127 is directed to the charger 123 for a new charging process. Waste toner removed from the peripheral surface of the photosensitive drum 121 by the cleaning device 127 is collected in a toner collection bottle (not shown) through a predetermined path.

  A paper transport path 111 is formed from the right position of the paper storage unit 14 to the lower part of the image forming unit 12. The sheet conveying path 111 is provided with a pair of conveying rollers 112 at appropriate positions, and the sheet from the sheet storage unit 14 is conveyed toward a position below the transfer belt 125 by driving the conveying roller pair 112. Yes. In the sheet conveyance path 111, a secondary transfer roller 113 that is in contact with the surface of the transfer belt 125 is provided at a position facing the pressing roller 125c. Then, the sheet P being conveyed through the sheet conveyance path 111 is pressed and sandwiched between the transfer belt 125 and the secondary transfer roller 113, whereby the toner image on the transfer belt 125 is transferred to the sheet P.

  The fixing unit 13 performs a fixing process on the toner image on the paper transferred by the image forming unit 12. The fixing unit 13 includes a heating roller 131 provided with an energization heating element such as a halogen lamp as a heating source, a fixing roller 132 disposed opposite to the heating roller 131, the fixing roller 132, and the heating roller 131. A fixing belt 133 stretched between the fixing belt 133 and a pressure roller 134 disposed opposite to the fixing belt 133 with the fixing roller 132 interposed therebetween.

  The paper P with the color image for which the fixing process has been completed passes through a paper discharge conveyance path 114 extending from the upper part of the fixing unit 13 and is discharged toward a paper discharge tray 115 provided on the left side wall of the apparatus main body 11. The

  The paper storage unit 14 has a paper tray 141 for storing a bundle of paper P, which is detachably mounted at a position below the exposure device 124 in the apparatus main body 11. In the example shown in FIGS. 5 and 6, the paper tray 141 is provided in two stages, but may be three or more stages, or may be one stage.

  Then, the paper P is fed out one by one by driving the pickup roller 142 from the paper bundle stored in the paper tray 141. The fed paper P is sent to a nip portion between the secondary transfer roller 113 and the transfer belt 125 of the image forming unit 12 through the paper conveyance path 111 and is formed on the surface of the transfer belt 125. A color toner image is transferred. The movement of the paper P after the transfer process is as described above.

  The drive unit 20 according to the present invention is applied to the image forming apparatus 10 configured as described above. FIG. 6 is a partially cutaway perspective view of the appearance of the image forming apparatus 10, and in which position the drive unit 20 is provided in the overall positional relationship in the image forming apparatus 10 can be easily understood. It is for doing so. FIG. 7 is a perspective view showing an example in which the drive unit 20 is applied to drive rotation of the photosensitive drum 121 and drive of the developing device 122 and the cleaning device 127. In addition, the direction display by X and Y in FIG. 7 is the same as in FIG. 1 (−X: leftward, + X: rightward, −Y: forward, + Y: backward).

  First, as shown in FIG. 6, the drive unit 20 outputs to the rear position of the four photosensitive drums 121 (the rightmost one is shown by a dotted line in FIG. 6) in the apparatus main body 11 of the image forming apparatus 10. The shaft 32 is disposed with the front facing forward. Each photosensitive drum 121 is driven and rotated by the corresponding first driving motor 30.

  As shown in FIG. 7, the photosensitive drum 121 has a drum shaft 121 a provided concentrically with the drum center position so as to be integrally rotatable. The drum shaft 121a is installed between a pair of front and rear frame plates 116 provided in the main body 11 of the image forming apparatus 10 so as to be rotatable about the axis. Thus, the photosensitive drum 121 is mounted at a predetermined position in the apparatus main body 11 so as to be integrally rotatable about the drum shaft 121a. The photosensitive drum 121 corresponds to the rotated body 82, the drum shaft 121a corresponds to the rotating shaft 81, and the frame plate 116 corresponds to the base frame 90.

  The drive unit 20 is attached to the rear frame plate 116. The frame plate 116 on the rear side of the pair of frame plates 116, the housing structure 40 provided on the frame plate 116 on the rear side, and the first and second provided on the rear side of the housing structure 40. The drive unit according to the present invention includes drive motors 30 and 39, a positioning holder 50 provided in the housing structure 40, and a bearing 60 fitted in both the front end of the positioning holder 50 and the frame plate 116. 20 is formed.

  The second drive motor 39 provided at the upper left of the first drive motor 30 in each unit 12M, 12C, 12Y, 12K is for driving the developing device 122 of the unit, and the first drive motor. A second drive motor 39 provided at the lower right of 30 is for driving the cleaning device 127 of the unit. Further, a gear mechanism for changing the rotational speed of the second drive motor 39 is provided between the erection plate 44 and the rear plate 45 of the housing structure 40.

  By applying the drive unit 20 according to the present invention to the image forming apparatus 10 to drive and rotate the photosensitive drum 121, the drum shaft 121a can be centered with high accuracy through the positioning holder 50, and in particular, it is installed in the construction. Since the holder insertion hole 441 formed in the plate 44 is a close fitting hole 441a, a long hole 441b, and an idiot hole 441c, the drum shaft 121a and the housing structure 40 are provided via the positioning holder 50. Since a strong interference state (so-called hell tightening or the like) between a plurality of sets of second drive motors 39 and gear mechanisms other than the drive motor 30 is eliminated, the developing device 122 and primary transfer linked to the drive rotation of the photosensitive drum 121 are eliminated. Driving of the roller 126 and the cleaning device 127 is performed properly, and as a result, it contributes to an appropriate image forming process without image defects. It can be.

  The present invention is not limited to the above embodiment, and includes the following contents.

  (1) In the above embodiment, an example in which the drive unit 20 according to the present invention is applied to the image forming apparatus 10 has been described. However, instead of the image forming apparatus 10, the driving force of the drive motor is applied to a predetermined rotating body. It can be applied to various devices configured to transmit.

  (2) In the above embodiment, a copying machine has been described as an example of the image forming apparatus 10 to which the driving unit 20 is applied. However, the driving unit is also used in an image forming apparatus such as a printer or a facsimile machine other than the copying machine. 20 can be applied.

  (3) In the above embodiment, the four first drive motors 30 are mounted on the drive unit 20, but the number is not limited to four, and may be three or less, or five. It may be the above.

It is a partially cutaway exploded perspective view showing an embodiment of a drive unit according to the present invention. FIG. 2 is a partially cut-out assembled perspective view of the drive unit shown in FIG. 1. FIG. 3 is a partially enlarged perspective view of FIG. 2 showing a tight fitting mounting structure in the drive unit. It is the IV-IV sectional view taken on the line of FIG. 1 is a front sectional view illustrating an outline of an internal structure of an embodiment of an image forming apparatus according to the present invention. FIG. 6 is a partially cutaway perspective view of the image forming apparatus shown in FIG. It is a perspective view showing an example in which a drive unit is applied to drive rotation of a photosensitive drum and drive of a developing device and a cleaning device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 11 Main body 111 Paper conveyance path 112 Conveyor roller pair 113 Secondary transfer roller 114 Paper discharge conveyance path 115 Paper discharge tray 116 Frame plate 12 Image forming unit 12M Magenta unit 12C Cyan unit 12Y Yellow unit 12K Black Unit 121 Photosensitive drum (image carrier)
121a drum shaft 122 developing device 123 charger 124 exposure device 125 transfer belt 125a driving roller 125b driven roller 125c pressing roller 126 primary transfer roller 127 cleaning device 13 fixing unit 131 heating roller 132 fixing roller 133 fixing belt 134 pressure roller 14 paper Storage unit 141 Paper tray 142 Pickup roller 15 Toner container 15M Magenta toner container 15C Cyan toner container 15Y Yellow toner container 15K Black toner container 16 Image reading unit 161 Document pressing cover 162 Optical system unit 163 Contact glass 17 Operation panel 171 Power switch 172 Numeric keypad 173 Start button 19 Intermediate hopper 20 Drive unit 30 Drive motor 31 Motor book 311 Boss 312 Projection piece 313 Mounting hole 32 Output shaft 321 D cut surface 39 Second drive motor 391 Drive shaft 392 Gear mechanism 40 Housing structure 41 Bottom plate 42 Top plate 43 Flange plate 431 Insertion hole 44 Installation plate (second unit frame plate) )
441 Holder insertion hole (second through hole)
441a Close fitting hole 441b Long hole 441c Stupid hole 442 Insertion hole 443 Drive shaft insertion hole 444 Bearing 45 Rear plate (first unit frame plate)
451 Boss support hole (third through hole)
452 Bolt hole 453 Non-rotating hole 46 Projection 461 Screw hole 47 Screw 50 Screw member 50 Positioning holder 51 Cylindrical holder body 511 Front circular hole 512 Rear circular hole 513 Central equal circular part 514 Rear equal circular part 52 Flange 521 Non-rotating protrusion 60 Bearing 70 Coupling member 71 D hole 80 Rotating member 81 Rotating shaft 811 D cut surface 82 Rotating body 90 Base frame 91 Insertion hole (first through hole) 92 Screw hole B Bolt P Paper

Claims (4)

A first unit frame plate integrally disposed opposite a base frame having a plurality of first through holes;
A second unit frame plate interposed between the base frame and the first unit frame plate;
A plurality of first drive motors arranged in parallel to the first unit frame plate through the first through holes corresponding to the output shafts;
A plurality of cylindrical positioning holders mounted on the first drive motors with the output shafts penetrating;
A plurality of second drive motors mounted on the first unit frame plate;
The second unit frame plate has a plurality of second through holes into which the positioning holders are fitted, and a plurality of third through holes that are tightly fitted to the drive shafts of the second drive motors. A through hole is drilled,
The second through hole is a close fitting hole in which one end is fitted in close contact with the outer peripheral surface of the positioning holder, and the other through hole is provided side by side with the second through hole. A drive unit characterized in that it is a long hole extending in the direction, and that between both ends is a foolish hole. Each of the first drive motors has a boss part through which each of the output shafts passes,
The drive unit according to claim 1, wherein the other end portion of each positioning holder is externally fitted to each boss portion. Each of the output shafts is passed through the corresponding first through hole via a bearing,
3. The drive unit according to claim 2, wherein each positioning holder is externally fitted to each of the bearings corresponding to an end opposite to the side externally fitted to the boss portion. A base frame,
A plurality of photosensitive drums each having a drum shaft and carrying a toner image;
A plurality of first drive motors having output shafts connected to the respective drum shafts; and a plurality of second drive motors for driving driven members other than the photosensitive drums;
4. The image forming apparatus according to claim 1, wherein the drive unit according to claim 1 is employed as an attachment structure of the plurality of first and second drive motors to the base frame.

Images