JP2008058356A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus that reduces noise and vibrations of a driving unit with simple constitution, and is improved in fitting workability of a guide member for a detachable unit and the driving unit and segregation operability for recycling. <P>SOLUTION: A resin-made unit support frame 23 which attachably and detachably supports a fixing unit 7 and a discharge unit 9 is fixed to a main body frame 21a made of sheet metal. For the unit support frame 23a, a guide rail 24a which slidably supports the fixing unit 7 and a guide groove 25a which slidably supports the discharge unit 9 are integrally formed. On the reverse side of the unit support frame 23a, a driving unit storage section 40 is formed which houses the driving unit 30 supplying driving power to the fixing unit 7 and discharge unit 9. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine and a printer, and more particularly to an image forming apparatus including a unit that can be attached to and detached from the apparatus main body in a horizontal direction.

  In a conventional image forming apparatus using an electrophotographic system, when performing a copying operation, an image forming unit arranged in the apparatus main body converts original image data onto a recording medium by charging, exposing, developing, and transferring processes. A predetermined toner image is formed based thereon. Then, after fixing (fixing) the unfixed toner image on the recording medium by the fixing step to form a permanent image, the recording medium is discharged to the outside of the apparatus main body.

  In such an image forming apparatus, if the fixing unit for fixing the toner image and the discharge unit on the downstream side thereof are detachable from the apparatus main body, the sheet is further removed when the sheet is jammed around the fixing unit. This facilitates the maintenance of the fixing unit. As a configuration in which the fixing unit is detachable, a method in which a guide member is attached to a frame on the apparatus main body side and the unit is slid horizontally along the guide member is generally used. Further, since the fixing unit and the discharging unit are provided with rotating bodies such as a fixing roller pair and a conveying roller pair, a driving unit for rotating these components is required.

  In the conventional configuration, a drive unit including a metal gear, a shaft, a motor, and the like is directly attached to a sheet metal main body frame, which causes a problem that vibration and noise increase. In addition, the shaft is attached to the main body frame by caulking or press-fitting, directly or via a mounting plate, and the guide member that supports the fixing unit is also attached to the main body frame with screws or the like. This separation work was also difficult.

As a method for easily assembling the drive mechanism, for example, in Patent Document 1, both the side plate frame of the apparatus main body and the drive system support frame attached to the side plate frame are formed of resin, and the gear train is sandwiched therebetween. An image forming apparatus configured as described above is disclosed. According to the configuration of Patent Document 1, although the gear support shaft, the E-ring and the like are not required and the assembly workability of the drive mechanism is improved, the entire side plate frame is formed of resin. The strength could be reduced. In addition, there is no description about the configuration for detachably supporting the unit, and the mounting workability of the guide member cannot be improved.
Japanese Patent Laid-Open No. 10-337929

  In view of the above-described problems, the present invention reduces the noise and vibration of the drive unit with a simple configuration, and also improves the mounting workability of the detachable unit guide member and drive unit and the separation workability during recycling. An object is to provide an apparatus.

  In order to achieve the above object, the present invention provides a pair of metal main body frames that are opposed to each other on the inner side of the apparatus main body, one or more detachable units supported in a bridging manner on the main body frame, And a drive unit for supplying a drive force to the detachable unit, wherein each main body frame is integrally formed with a resin member in which a guide member for slidably supporting the detachable unit is formed. A support frame is fixed, and one unit support frame is characterized in that a drive unit storage portion for storing the drive unit is formed on the back side of the guide member.

  According to the present invention, in the image forming apparatus configured as described above, a plurality of the detachable units are provided, and the drive unit is integrated with a drive mechanism that drives the plurality of detachable units.

  According to the present invention, in the image forming apparatus configured as described above, the detachable unit is a fixing unit and a discharge unit.

  According to the present invention, in the image forming apparatus configured as described above, the motor constituting the drive unit is an inner rotor type brushless motor.

  According to the first configuration of the present invention, the guide member that supports the detachable unit is integrally formed with the resin unit support frame, thereby reducing the number of parts and improving the assembly and disassembly workability. This contributes to cost reduction and recycling of the image forming apparatus. In addition, since the drive unit is housed in the drive unit housing portion formed in the unit support frame, the soundproofing effect against the drive sound of the motor and gear in the drive unit is enhanced, and vibration is transmitted to the metal body frame. Is also suppressed.

  According to the second configuration of the present invention, in the image forming apparatus having the first configuration, the drive mechanism for driving the plurality of detachable units is integrated as a drive unit, so that the drive mechanism can be attached. Efficiency and space saving of the image forming apparatus can be achieved.

  According to the third configuration of the present invention, in the image forming apparatus having the second configuration, the detachable unit is a fixing unit and a discharge unit in which the drive mechanism is positioned close to each other. Can be easily integrated.

  According to the fourth configuration of the present invention, in the image forming apparatus having any one of the first to third configurations, the drive unit is formed by using the inner rotor type brushless motor as the motor configuring the drive unit. In addition, it is possible to suppress noise and vibration peculiar to the inner rotor type brushless motor.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing the configuration of an image forming apparatus according to the present invention. Here, a tandem color printer is shown. In the main body of the image forming apparatus 100, four image forming portions Pa, Pb, Pc, and Pd are sequentially arranged from the upstream side (right side in FIG. 1) of the transfer belt 8. These image forming portions Pa to Pd are provided corresponding to images of four different colors (for example, magenta, cyan, yellow, and black), and magenta, cyan, and cyan are respectively obtained by charging, exposure, development, and transfer processes. Yellow and black images are sequentially formed.

  Photosensitive drums 1a, 1b, 1c, and 1d that carry visible images (toner images) of the respective colors are disposed in the image forming portions Pa to Pd, and are formed on the photosensitive drums 1a to 1d. The transferred toner image is transferred onto a sheet 6 carried and conveyed by a transfer belt 8 that moves adjacent to each image forming unit, and is further fixed on the sheet 6 by a fixing unit 7. It is configured to be discharged. An image forming process for each of the photosensitive drums 1a to 1d is executed while rotating the photosensitive drums 1a to 1d clockwise in FIG.

  Next, the image forming units Pa to Pd will be described. Around and around the photosensitive drums 1a to 1d rotatably arranged, image information is supplied to the chargers 2a, 2b, 2c and 2d for charging the photosensitive drums 1a to 1d and the photosensitive drums 1a to 1d. LED heads 17a, 17b, 17c and 17d to be exposed, developing devices 3a, 3b, 3c and 3d for forming toner images on the photosensitive drums 1a to 1d, and a developer remaining on the photosensitive drums 1a to 1d ( Cleaning portions 5a, 5b, 5c and 5d for removing toner are provided.

  First, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the chargers 2a to 2d, then irradiated with light by the LED heads 17a to 17d, and electrostatic charges corresponding to the image signals are applied to the photosensitive drums 1a to 1d. A latent image is formed. Each of the developing devices 3a to 3d is filled with a predetermined amount of magenta, cyan, yellow, and black toners by a replenishing device (not shown). The toner is supplied onto the photosensitive drums 1a to 1d by the developing units 3a to 3d and electrostatically attached to the toner corresponding to the electrostatic latent images formed by exposure from the LED heads 17a to 17d. An image is formed.

  The paper 6 onto which the toner image is transferred is housed in a paper feed cassette 16 at the lower part of the apparatus, and is fed to the paper transport path 12 by a paper feed mechanism comprising a pickup roller 13a and a paper feed roller pair 13b. Then, the toner is supplied onto the transfer belt 8 via the registration roller pair 14 and conveyed to the positions of the photosensitive drums 1a to 1d. As the transfer belt 8, a belt in which both ends thereof are overlapped with each other and joined to form an endless shape or a seamless belt is used. As a material of the belt, a resin belt is used, and preferably a multilayer rubber belt in which a fluorine resin coating, a silicon coat, a CR rubber, and a PVDF resin sheet are sequentially laminated from the surface layer is used.

  The transfer belt 8 is stretched around the driven rollers 10a to 10c and the driving roller 11. When the transfer belt 8 starts to rotate counterclockwise, the sheet 6 is transferred from the registration roller pair 14b to the most upstream side of the transfer belt 8. Is conveyed onto the transfer belt 8 via a suction roller 15 provided on the transfer belt 8. A predetermined voltage is applied to the suction roller 15, and the paper 6 is held on the transfer belt 8 by an electrostatic suction force.

  At this time, the image writing signal is turned ON, and an image is formed on the uppermost photosensitive drum 1a at a predetermined timing. A magenta toner image on the photosensitive drum 1a is transferred onto the paper 6 by applying an electric field to the lower portion of the photosensitive drum 1a with the transfer roller 4a to which a predetermined transfer voltage is applied. Thereafter, the sheet 6 is conveyed to the next image forming unit Pb, and a cyan toner image is transferred by the photosensitive drum 1b in the same manner as described above.

  Thereafter, yellow and black toner images are transferred by the photosensitive drums 1c and 1d by the same method as described above. These four-color images are formed with a predetermined positional relationship that is predetermined with respect to the paper 6 in order to form a predetermined full-color image. Reference numerals 4b, 4c and 4d denote transfer rollers located below the photosensitive drums 1b to 1d. The paper 6 on which the four color toner images are transferred is separated from the transfer belt 8 and conveyed to the fixing unit 7. In addition, the photosensitive drums 1a to 1d after the toner images are transferred are prepared by the cleaning units 5a to 5d in preparation for new electrostatic latent images to be subsequently formed.

  The sheet 6 conveyed from the transfer belt 8 to the fixing unit 7 is heated and pressed by the fixing roller pair 18 so that the toner image is fixed on the surface of the sheet 6 and a predetermined full-color image is formed. The sheet 6 on which the full-color image is formed is discharged out of the apparatus main body through a discharge unit 9 having a conveyance roller pair 19 and a discharge roller pair 20.

  2 and 3 are perspective views showing the main body frames on the back side and the front side of the image forming apparatus. The main body frames 21a and 21b are made of sheet metal, and the driven rollers 10a to 10c, the driving roller 11, various rollers constituting the image forming portions Pa to Pd, or frame members for connecting the main body frames 21a and 21b are provided on the side surfaces thereof. A large number of through-holes 22 are arranged at predetermined positions. Resin-made unit support frames 23a and 23b that detachably support the fixing unit 7 and the discharge unit 9 (see FIG. 1) are fixed to the main body frames 21a and 21b, respectively.

  Guide rails 24a and 24b that slidably support the fixing unit 7 and guide grooves 25a and 25b that slidably support the discharge unit 9 are integrally formed on the unit support frames 23a and 23b. With this configuration, there is no need to attach a guide member separately, the number of parts is reduced, and the assembly workability and the disassembly workability at the time of disposal of the apparatus are improved, so that the cost of the image forming apparatus can be reduced and the parts can be reduced. It becomes easy to recycle. Further, on the back surface of the unit support frame 23a fixed to the main body frame 21a side, a drive unit storage section 40 (see FIG. 6) for storing a drive unit 30 (see FIG. 6) for supplying driving force to the fixing unit 7 and the discharge unit 9 is provided. 7) is formed.

  4 is a perspective view of the fixing unit 7 as viewed from the upstream side in the insertion direction (left side in FIG. 1). The fixing unit 7 includes a fixing roller pair 18 (see FIG. 1) in a resin-made fixing housing 26, and a transfer paper that has passed through the fixing roller pair 18 is discharged to the upper portion of the fixing housing 26 (see FIG. 1). 4 pairs of conveying rollers 19a are provided in the width direction. At both left and right ends of the fixing housing 26, flange portions 26a and 26b supported by guide rails 24a and 24b (see FIGS. 2 and 3) formed on the unit support frames 23a and 23b are formed.

  FIG. 5 is a perspective view of the discharge unit 9 as viewed from the upstream side in the insertion direction (left side in FIG. 1). The discharge unit 9 includes four pairs of transport rollers 19b and discharge roller pairs 20 in a resin unit main body 28. The transport rollers 19b are connected to a transport roller 19a (see FIG. 4) provided in the fixing unit 7. A pair of conveying rollers 19 (see FIG. 1) is formed by pressure contact. Boss portions 28a and 28b that are engaged and supported in guide grooves 25a and 25b (see FIGS. 2 and 3) formed in the unit support frames 23a and 23b are formed on the left and right ends of the unit main body 28, respectively.

  Next, the unit support frame and the drive unit will be described in detail. FIG. 6 is a perspective view of the drive unit and the unit support frame, and FIGS. 7 and 8 are perspective views of the unit support frame to which the drive unit is mounted as viewed from the drive unit side and the opposite side. Here, the unit support frame 23a on the main body frame 21a side will be described. However, the unit support frame 23b on the main body frame 21b side has the same configuration except for whether or not the drive unit is mounted, and thus the description thereof is omitted.

  As shown in FIG. 6, the drive unit 30 includes a fixing support motor 32 (see FIG. 7), a discharge drive motor 33, gears 34 a to 34 e, and a fixing drive output gear on metal support plates 31 a and 31 b connected to each other. 35, a discharge drive output gear 36 and the like are attached, and the driving force from the fixing drive motor 32 is transmitted to the fixing drive output gear 35 through a gear train including gears 34a and 34b, and the drive from the discharge drive motor 33 is performed. The force is transmitted to the discharge drive output gear 36 through a gear train including gears 34c to 34e. That is, the drive unit 30 is a unit in which the drive mechanism of the fixing unit 7 and the drive mechanism of the discharge unit 9 are integrated.

  Here, an inner rotor type brushless motor is used as the fixing drive motor 32 and the discharge drive motor 33. In addition, openings 29a and 29b are formed in a part of the guide rail 24a of the unit support frame 23a and below the guide groove 25a.

  As shown in FIG. 7, a drive unit housing portion 40 is formed on the surface of the unit support frame 23a opposite to the surface on which the guide rail 24a and the guide groove 25a are formed. By storing the drive unit 30 in the drive unit storage section 40 and fixing it with screws, the unit support frame 23a and the drive unit 30 are united, and the drive unit 30 can be mounted only by fixing the unit support frame 23a to the main body frame 21a. It can be easily attached to the main body frame 21a.

  Further, as shown in FIG. 8, only a part of the fixing drive output gear 35 and the discharge drive output gear 36 are exposed from the openings 29a and 29b, and the drive on the side of the fixing unit 7 and the discharge unit 9 (see FIGS. 4 and 5). It can be connected to the input gear. As a result, most of the fixing drive output gear 35 and the discharge drive output gear 36 are covered with the resin member, so that after the fixing unit 7 or the discharge unit 9 is removed, the user inserts his / her hand for jamming or the like. Sometimes the possibility of directly touching the gear is reduced, and the structure is excellent in terms of safety and design.

  Further, since the drive unit 30 is mounted on the metal main body frame 21a via the resin unit support frame 23a, transmission of vibration is suppressed. Furthermore, since the drive unit storage portion 40 that stores the drive unit 30 so as to be included is formed, a soundproofing effect on the drive sound of the motor and gears constituting the drive unit 30 can be expected.

  In particular, an inner rotor type brushless motor having a rotor inside a stator (stator) is more compact than an out rotor type having a rotor (rotor) on the outside, but has a smaller number of coil phases. Therefore, in order to rotate smoothly, it is necessary to use at high rotation, which is disadvantageous for vibration and noise. However, with the configuration of the present invention housed in the resin drive unit housing section 40, vibration and noise transmission can be effectively suppressed.

  9 and 10 are perspective views of the state in which the fixing unit 7 and the discharge unit 9 are inserted into the apparatus main body as viewed from the downstream side (right side in FIG. 1) and the upstream side (left side in FIG. 1). For convenience of explanation, the main body frame 21b and the unit support frame 23b on the front side of the apparatus and the drive unit 30 in the unit support frame 23a are not shown.

  9 and 10, the flange portion 26a (see FIG. 4) of the fixing unit 7 and the boss portion 28a (see FIG. 5) of the discharge unit 9 are inserted to predetermined positions along the guide rail 24a and the guide groove 25a. Thus, a drive input gear (not shown) provided on the fixing unit 7 and discharge unit 9 side is connected to the fixing drive output gear 35 (see FIG. 8) and the discharge drive output via the openings 29a and 29b (see FIG. 8). The gear 36 is connected. Accordingly, the positioning and the driving mechanism can be easily connected when the fixing unit 7 and the discharge unit 9 are mounted on the apparatus main body.

  In addition, when attaching and detaching the fixing unit 7 and the discharge unit 9, it is necessary to open and close the side cover of the apparatus main body, and usually an open / close switch for detecting opening and closing of the side cover is provided on the apparatus main body side. The open / close switch needs to be provided with a resin switch cover for preventing static electricity charged on the human body from being discharged to the switch. If only the main body frame 21a (or 21b) made of sheet metal is used, a resin switch cover is required separately. However, in the configuration of the present invention, the unit support frame 23a (or 23b) is made of resin. The switch cover can be integrally formed.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in the above-described embodiment, the image forming apparatus configured to pull out the fixing unit 7 and the discharge unit 9 horizontally has been described. However, the unit pulled out of the apparatus is not limited to the fixing unit 7 and the discharge unit 9. For example, other units such as a transfer unit including a transfer roller may be used.

  In addition, the present invention is not limited to the tandem color printer shown in FIG. 1, and an intermediate transfer method in which toner images of respective colors are sequentially stacked on an intermediate transfer belt to form a color image and then transferred onto a sheet at a time. The present invention can be applied to other color image forming apparatuses and monochrome image forming apparatuses, and can be applied to other types of image forming apparatuses such as digital multifunction peripherals, analog copying machines, facsimile machines, and laser printers. . In the intermediate transfer type image forming apparatus, the intermediate transfer unit may be pulled out in the sheet conveyance direction together with the fixing unit 7 or alone.

  The present invention includes a pair of metal main body frames that are arranged opposite to each other on the inner side of the apparatus main body, one or more detachable units that are supported by the main body frame in a bridging manner, and a driving force applied to the detachable units. In each of the main body frames, a resin unit support frame integrally formed with a guide member that slidably supports the detachable unit is fixed, In the unit support frame, a drive unit storage portion for storing the drive unit is formed on the back side of the guide member.

  As a result, the number of parts can be reduced, the assembling and disassembling workability can be improved, and an image forming apparatus that is low in cost and excellent in recyclability can be provided. In addition, the image forming apparatus is highly effective in suppressing vibration and driving sound of the motor and gear in the driving unit.

  In addition, since the drive mechanism that drives a plurality of detachable units such as the fixing unit and the discharge unit is integrated and stored in the drive unit storage portion, an image that realizes efficiency in mounting the drive mechanism and space saving is realized. It becomes a forming device. In particular, when an inner rotor type brushless motor is used for the drive unit, noise and vibration peculiar to the inner rotor type brushless motor can be suppressed while realizing a compact drive unit.

FIG. 2 is a side sectional view showing a configuration of a tandem color image forming apparatus which is an example of the image forming apparatus of the present invention. FIG. 3 is a perspective view showing a main body frame on the back side of the image forming apparatus. FIG. 3 is a perspective view showing a main body frame on the front side of the image forming apparatus. FIG. 3 is an external perspective view of a fixing unit mounted in the image forming apparatus of the present invention. FIG. 3 is an external perspective view of a discharge unit mounted on the image forming apparatus of the present invention. These are perspective views of a drive unit and a unit support frame mounted on the image forming apparatus of the present invention. FIG. 5 is a perspective view of a unit support frame on which the drive unit is mounted as viewed from the drive unit side. FIG. 5 is a perspective view of a unit support frame on which the drive unit is mounted as viewed from the opposite side of the drive unit. FIG. 4 is a perspective view of a state where the fixing unit and the discharge unit are inserted into the apparatus main body, as viewed from the downstream side in the insertion direction (the right side in FIG. 1). FIG. 3 is a perspective view of a state where the fixing unit and the discharge unit are inserted into the apparatus main body, as viewed from the upstream side in the insertion direction (left side in FIG. 1).

Explanation of symbols

7 Fixing unit (detachable unit)
9 Discharge unit (detachable unit)
21a, 21b Main body frame 23a, 23b Unit support frame 24a, 24b Guide rail (guide member)
25a, 25b Guide groove (guide member)
26 Fixing housing 26a, 26b Flange portion 28 Discharge unit main body 28a, 28b Boss portion 30 Drive unit 31a, 31b Support plate 32 Fixing drive motor 33 Discharge drive motor 34a-34e Gear 35 Fixation drive output gear 36 Discharge drive output gear 40 Drive unit Storage unit 100 Image forming apparatus

Claims (4)

A pair of metal main body frames opposed to the inner side surface of the apparatus main body, one or more detachable units supported in a bridging manner on the main body frame, and a drive unit for supplying driving force to the detachable units In an image forming apparatus comprising:
A resin unit support frame integrally formed with a guide member that slidably supports the detachable unit is fixed to each main body frame, and the drive unit is mounted on one of the unit support frames. An image forming apparatus, wherein a drive unit storage portion to be stored is formed on a back surface side of the guide member.   The image forming apparatus according to claim 1, wherein a plurality of the detachable units are provided, and the drive unit is integrated with a drive mechanism that drives the plurality of detachable units.   The image forming apparatus according to claim 2, wherein the detachable unit is a fixing unit and a discharge unit.   4. The image forming apparatus according to claim 1, wherein the motor constituting the drive unit is an inner rotor type brushless motor.