JP2011197639A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus having an image carrier attached to the image forming apparatus with high accuracy by using a relatively small number of components.SOLUTION: The image forming apparatus includes: a main plate including a first surface and a second surface on the opposite side to the first surface; the image carrier arranged on the first surface side and formed to carry an image formed on a sheet; and a driving mechanism attached to the second surface and including a transmission part transmitting driving force to a rotary shaft of the image carrier. The driving mechanism includes a positioning cylinder penetrating the main plate from the second surface to the first surface, and the transmission part is connected to the rotary shaft inserted into the positioning cylinder.

Description

  The present invention relates to an image forming apparatus that forms an image on a sheet.

  In general, an image forming apparatus such as a copier, a printer, a facsimile, or a multifunction machine having these functions forms a toner image using a photosensitive drum that is rotatably supported in a casing. While the toner is formed on the peripheral surface of the photosensitive drum or while the toner image is transferred from the photosensitive drum to the sheet, the photosensitive drum rotates. Therefore, the mounting accuracy of the photosensitive drum greatly affects the quality of the image formed on the sheet.

  Patent Document 1 discloses an image forming apparatus including a photosensitive drum connected via a coupling to a drive shaft rotatably supported by a casing. The shaft of the photosensitive drum is aligned so as to be substantially coaxial with the drive shaft, and is connected using a coupling.

JP 2003-5475 A

  According to the technique disclosed in Patent Document 1, a specially shaped flange is used at the connecting portion between the drive shaft and the photosensitive drum in order to improve the mounting accuracy of the photosensitive drum. However, since the mounting of the photosensitive drum of Patent Document 1 is performed on a drive shaft that is rotatably mounted on the housing, a significant improvement in mounting accuracy cannot be expected. In addition, the disclosed technique of Patent Document 1 requires a large number of components such as an encoder and a bearing that needs to be accurately attached to the housing in order to improve the rotational accuracy of the photosensitive drum.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus having an image carrier attached to the image forming apparatus with high accuracy by using relatively few parts. And

  An image forming apparatus according to one aspect of the present invention includes a main plate including a first surface, a second surface opposite to the first surface, and a first plate disposed on the first surface and formed on a sheet. An image carrier formed so as to be capable of carrying an image to be carried, and a drive mechanism that is attached to the second surface and includes a transmission unit that transmits a driving force to a rotation shaft of the image carrier, and the drive mechanism Includes a positioning cylinder penetrating the main plate from the second surface toward the first surface, and the transmission portion is connected to the rotating shaft inserted into the positioning cylinder. Item 1).

  According to the above configuration, the image forming apparatus includes the image carrier that has the rotating shaft and is formed so as to be capable of carrying the image formed on the sheet. An image carrier is disposed on the first surface side of the main plate, and a drive mechanism is disposed on the second surface side of the main plate. The drive mechanism includes a positioning cylinder that penetrates the main plate. The rotating shaft is inserted into the positioning cylinder, and a driving force is transmitted from the driving mechanism. Thus, since the rotating shaft is inserted into the positioning cylinder and attached to the image forming apparatus, the image carrier is attached to the main plate of the image forming apparatus with high accuracy using relatively few parts.

  The said structure WHEREIN: It is preferable that the said drive mechanism contains the housing | casing which accommodates the said transmission part, and the said positioning cylinder is formed in the said housing | casing (Claim 2).

  According to the above configuration, the rotating shaft is formed in the casing that accommodates the transmitting portion and is inserted into the positioning cylinder that penetrates the main plate, and the driving force is transmitted from the driving mechanism. Thus, since the rotating shaft is inserted into the positioning cylinder and attached to the image forming apparatus, the image carrier is attached to the main plate of the image forming apparatus with high accuracy using relatively few parts.

  In the above configuration, the apparatus further includes a drive source that generates the driving force, and a support plate that is attached to an outer surface of the housing and supports the drive source, and the support plate is inserted into the housing through the positioning cylinder. It is preferable to include a support cylinder that rotatably supports the inserted rotation shaft.

  According to the above configuration, the rotating shaft is formed in the housing that accommodates the transmission portion, and is inserted into the positioning cylinder penetrating the main plate and is rotatably supported by the supporting cylinder of the supporting plate. Thus, the image carrier is attached to the main plate of the image forming apparatus with high accuracy using relatively few parts.

  In the above configuration, the drive source includes a motor, and the transmission unit is connected to a drive gear connected to the shaft of the motor, and a relay gear that meshes with the drive gear and is rotatably supported by the support cylinder. It is preferable that the relay gear includes a coupling for connecting the rotating shaft (claim 4).

  According to the above configuration, the transmission unit in the housing includes the drive gear connected to the shaft of the motor and the relay gear that meshes with the drive gear and is rotatably supported by the support cylinder. The rotating shaft supported by the support cylinder is connected to the relay gear by coupling. Thus, the image carrier is rotatably attached to the main plate of the image forming apparatus with high accuracy using relatively few parts.

  In the above configuration, the drive mechanism includes a conductive grounding element including a first end connected to the support plate and a second end connected to the main plate, and the main plate and the support plate Preferably has conductivity.

  According to the above configuration, the ground element includes the first end connected to the support plate and the second end connected to the main plate. Since the main plate, the support plate, and the grounding element are conductive, proper grounding is provided for the electricity supplied to the motor.

  The said structure WHEREIN: The said housing | casing contains the 1st holding | maintenance part holding the said 1st end part, The said 1st end part hold | maintained at this 1st holding | maintenance part is wound by the coil shape, The said support plate Preferably compresses the first end (claim 6).

  According to the said structure, the 1st holding | maintenance part of a housing | casing hold | maintains the 1st edge part wound by the coil shape. Since the support plate compresses the first end portion, the contact between the first end portion and the support plate is appropriately maintained. Therefore, appropriate grounding for the electricity supplied to the motor is provided.

  The said structure WHEREIN: The said housing | casing contains the 2nd holding | maintenance part holding the said 2nd end part, and the said 2nd end part wound by coil shape is between the said 2nd holding | maintenance part and the said main board. It is preferably compressed (claim 7).

  According to the said structure, the 2nd holding | maintenance part of a housing | casing hold | maintains the 2nd edge part wound by the coil shape. Since the second end portion is compressed between the second holding portion and the main plate, the contact between the second end portion and the main plate is appropriately maintained. Therefore, appropriate grounding for the electricity supplied to the motor is provided.

  As described above, the present invention can provide an image forming apparatus having an image carrier attached to the image forming apparatus with high accuracy using relatively few parts.

1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment. FIG. 2 is a perspective view schematically showing attachment of a photosensitive drum of the image forming apparatus shown in FIG. 1. FIG. 2 is a cross-sectional view schematically showing attachment of the photosensitive drum of the image forming apparatus shown in FIG. 1. FIG. 3 is a perspective view of the frame shown in FIG. 2. It is a perspective view of the drive mechanism attached to the flame | frame shown by FIG. It is a perspective view of the drive mechanism attached to the flame | frame shown by FIG. It is a perspective view of the flame | frame with which the drive mechanism was attached. FIG. 7 is a perspective view of a second outer shell of the drive mechanism shown in FIGS. 5 and 6. It is a perspective view of the transmission part constructed | assembled by the 2nd outer shell body shown by FIG. It is a perspective view of the support plate for attaching the motor of the drive mechanism shown in FIG.5 and FIG.6. It is a perspective view of the support plate for attaching the motor of the drive mechanism shown in FIG.5 and FIG.6. It is a perspective view of the drive mechanism used for the image forming apparatus which concerns on 2nd Embodiment. FIG. 13 is an enlarged perspective view around a ground wire of the drive mechanism shown in FIG. 12. FIG. 13 is a perspective view of a ground wire of the drive mechanism shown in FIG. 12.

  Hereinafter, various embodiments of an image forming apparatus will be described with reference to the accompanying drawings. The terms representing the directions such as “up”, “down”, “left”, and “right” used in the following description are merely for the purpose of clarifying the explanation, and the principle of the drive mechanism and the image forming apparatus. It is not limited at all. In the following description, the term “sheet” means copy paper, coated paper, OHP sheet, cardboard, postcard, tracing paper, and other sheet materials that are subjected to image forming processing. The terms “upstream”, “downstream” and similar terms used in the following description mean “upstream”, “downstream” and similar concepts in the sheet conveyance direction.

<First Embodiment>
FIG. 1 schematically shows an image forming apparatus according to the first embodiment. In this embodiment, a copier is exemplified as the image forming apparatus. Alternatively, the image forming apparatus may be a printer, a facsimile, a multifunction machine having these functions, or another apparatus capable of forming an image on a sheet.

(Overall structure of image forming apparatus)
The copying machine 100 includes a main housing 110 that houses equipment required to form a toner image, and a document supply device 120 that is disposed on the upper surface of the main housing 110. The main housing 110 includes a lower housing 111, an upper housing 112 disposed above the lower housing 111, and a connection housing 113 disposed between the lower housing 111 and the upper housing 112. Including. In the space R surrounded by the lower casing 111, the upper casing 112, and the connection casing 113, the sheet S that has been subjected to the printing process is discharged.

  The upper housing 112 mainly accommodates a device for reading a document on which a toner image is based. The lower housing 111 accommodates a device for forming a toner image on the sheet S. The connection housing 113 accommodates a device for discharging the sheet S on which the toner image is formed. The copying machine 100 further includes an operation panel (not shown) attached to the outer surface of the main housing 110. The user can give a desired instruction to the copying machine 100 by operating the operation panel.

  The document feeder 120 is attached to the main housing 110 so as to rotate up and down. The user places a desired document on the document feeder 120. Thereafter, the user can operate the operation panel to operate the document supply device 120 and send the document between the lower surface of the document supply device 120 and the upper surface of the main housing 110. Alternatively, the user rotates the document supply device 120 upward, places the document on the upper surface of the main housing 110, and then rotates the document supply device 120 downward, so that the document is main. It can be disposed between the upper surface of the housing 110 and the lower surface of the document feeder 120.

  The copying machine 100 further includes a scanning mechanism 114 that scans and reads a document disposed between the lower surface of the document supply device 120. The scanning mechanism 114 is disposed in the upper housing 112. The scanning mechanism 114 scans and optically reads an image attached to a document. Thereafter, the scanning mechanism 114 outputs the read image as a digital signal.

  The copying machine 100 further includes a cassette 210 that stores a sheet S on which a toner image based on a digital signal output from the scanning mechanism 114 is formed. The cassette 210 disposed in the lower casing 111 includes a lift plate 211 and a lifting mechanism 212 for rotating the downstream end (right end in FIG. 1) of the lift plate 211 up and down in the cassette 210. . The user places the bundle of sheets S on the lift plate 211. As a result of the lifting mechanism 212 pushing up the downstream end of the lift plate 211, the sheet S is conveyed from the cassette 210.

  The copying machine 100 further includes a manual feed tray 220 rotatably attached to the left side plate of the lower housing 111. The user may place the sheet S on the manual feed tray 220 rotated so as to protrude from the left side plate of the lower housing 111. The sheet S on the manual feed tray 220 is drawn into the lower housing 111. The copier 100 performs a toner image forming process on the sheet S drawn into the lower casing 111.

  The cassette 210 and the manual feed tray 220 are used as a sheet S supply source. The user can select the cassette 210 or the manual feed tray 220 that stores sheets S of a desired size through the operation of the operation panel. The sheet S arranged in the selected sheet supply source (cassette 210, manual feed tray 220) is conveyed in the lower casing 111 and subjected to image forming processing.

  The copying machine 100 further includes a pickup roller 311 disposed above the lift plate 211. When the lifting mechanism 212 raises the downstream end of the lift plate 211, the sheet S on the lift plate 211 comes into contact with the pickup roller 311. The pickup roller 311 rotates so as to send the sheet S out of the cassette.

  The copying machine 100 further includes a paper feed roller 312 disposed downstream of the pickup roller 311 and a separating roller 313 adjacent to the paper feed roller 312. The paper feed roller 312 is disposed on the upper side of the separating roller 313. The sheet S sent out from the cassette 210 by the pickup roller 311 is sent between the paper feed roller 312 and the separating roller 313. The paper feed roller 312 rotates to send the sheet S further downstream, and the separation roller 313 rotates to return the sheet S to the cassette 210. As a result, when the sheet S having a plurality of pickup rollers 311 overlapped is sent out from the cassette 210, only the sheet S that contacts the paper feed roller 312 (the uppermost sheet S) is sent downstream, and the other sheets S are Returned to cassette 210. Thus, the sheets S are sent downstream one by one.

  The copier 100 further includes a paper feed roller 316 disposed in the vicinity of the proximal end portion of the manual feed tray 220 and a separating roller 317 pressed against the paper feed roller 316. The sheet S placed on the manual feed tray 220 is drawn into the lower housing 111 by the paper feed roller 316. The sheet S drawn into the lower housing 111 by the paper feed roller 316 passes between the paper feed roller 316 and the separating roller 317. When the sheet feeding roller 316 tries to draw a plurality of sheets S into the lower housing 111, the winding roller 313 rotates to return the sheet S to the manual feed tray 220. As a result, only the sheet S (the uppermost sheet S) in contact with the sheet feeding roller 316 is drawn into the lower housing 111. Thus, the sheets S are fed from the manual feed tray 220 into the lower housing 111 one by one.

  The copying machine 100 further includes an image forming unit 400 that forms an image on the sheet S, and a registration roller pair 318 for feeding the sheet S to the image forming unit 400. The sheet S sent out from the cassette 210 or the manual feed tray 220 goes to the registration roller pair 318. The image forming unit 400 formed downstream of the registration roller pair 318 forms a toner image based on the digital signal output from the scanning mechanism 114, and then transfers the toner image to the sheet S. The registration roller pair 318 sends the sheet S to the image forming unit 400 in synchronization with the image forming process of the image forming unit 400. Thus, a toner image is formed at a predetermined position on the sheet S.

  In the present embodiment, the pickup roller 311, the paper feed rollers 312 and 316, the separating rollers 313 and 317, and the registration roller pair 318 are used as a supply unit that supplies the sheet S to the image forming unit 400.

  The image forming unit 400 includes a substantially cylindrical photosensitive drum 410. As will be described later, the photosensitive drum 410 includes a rotating shaft and is rotatably supported in the lower housing 111. After the electrostatic latent image is formed on the peripheral surface of the photosensitive drum 410, a toner image that matches the electrostatic latent image is formed. Thereafter, the photosensitive drum 410 rotates while carrying the toner image, and the toner image is transferred to the sheet S sent to the image forming unit 400 by the registration roller pair 318. In the present embodiment, the photosensitive drum 410 is exemplified as an image carrier.

  The image forming unit 400 further includes a charger 411 and an exposure device 412. The charger 411 uniformly charges the peripheral surface of the photosensitive drum 410. The exposure device 412 irradiates the peripheral surface of the photosensitive drum 410 with laser light based on the digital signal output from the scanning mechanism 114. As the charge of the portion irradiated with the laser light disappears, an electrostatic latent image that matches the image shown on the original is formed on the peripheral surface of the photosensitive drum 410.

  The image forming unit 400 further includes a toner container 413 that contains toner, and a developing device 414 that supplies the toner supplied from the toner container 413 to the photosensitive drum 410. The developing device 414 supplies toner to the photosensitive drum 410 that rotates while carrying an electrostatic latent image. The toner supplied from the developing device 414 to the photosensitive drum 410 is electrostatically attached to the peripheral surface of the photosensitive drum 410. As a result, a toner image is formed on the peripheral surface of the photosensitive drum 410.

  The image forming unit 400 further includes a transfer roller 415 that is pressed against the photosensitive drum 410. The registration roller pair 318 feeds the sheet S between the photosensitive drum 410 and the transfer roller 415. The transfer roller 415 gives the sheet S a bias opposite to that of the toner carried by the photosensitive drum 410. As a result, the toner on the photosensitive drum 410 is electrically peeled off from the surface of the sheet S, and the toner image is transferred to the sheet S. Thereafter, the photosensitive drum 410 and the transfer roller 415 send the sheet S downstream.

  The image forming unit 400 further includes a cleaning device 416 and a static eliminator 417. The cleaning device 416 removes the toner remaining on the peripheral surface of the photosensitive drum 410 after the toner image is transferred to the sheet S. Thereafter, the static eliminator 417 neutralizes the peripheral surface of the cleaned photosensitive drum 410. Thereafter, the photosensitive drum 410 is uniformly charged again by the charger 411 and undergoes a new image forming process.

  The copying machine 100 further includes a fixing unit 500 that fixes the toner image formed by the image forming unit 400 to the sheet S. The fixing unit 500 disposed downstream of the image forming unit 400 includes a heating roller 510 incorporating a heater 511 and a pressure roller 520 pressed against the heating roller 510. The photosensitive drum 410 and the transfer roller 415 send the sheet S between the heating roller 510 and the pressure roller 520.

  The toner on the sheet S is melted by the heat energy from the heating roller 510. The toner image is fixed on the sheet S by the pressure generated between the heating roller 510 and the pressure roller 520. Thereafter, the heating roller 510 and the pressure roller 520 send the sheet S downstream.

  The copier 100 further includes a discharge unit 600 formed downstream of the fixing unit 500. The discharge unit 600 includes a discharge roller pair 610. When the user gives an instruction for single-sided printing to the copying machine 100 through the operation panel, the discharge roller pair 610 discharges the sheet S sent from the fixing unit 500 to the space R. When the user gives an instruction for double-sided printing to the copying machine 100 through the operation panel, the discharge roller pair 610 pulls the sheet S back into the connection housing 113 in the direction in which the sheet S is discharged into the space R. A switchback operation is performed to switch the rotation direction between directions.

  The copying machine 100 includes a supply conveyance path 320 that guides the sheet S from the cassette 210 and / or the manual feed tray 220 to the registration roller pair 318, and a return conveyance path 319 formed along the right side plate of the main casing 110. Are further provided. The lower end (downstream end) of the return conveyance path 319 is connected to the supply conveyance path 320. In response to a double-sided printing instruction from the user, the sheet S that has been pulled back into the connection casing 113 by the switchback operation is sent upstream of the registration roller pair 318 through the return conveyance path 319. Thereafter, the sheet S passes through the image forming unit 400 and the fixing unit 500. As a result, toner images are formed on both sides of the sheet S. The sheet S subjected to the duplex printing process is discharged into the space R by the discharge roller pair 610.

(Frame structure)
FIG. 2 is a schematic perspective view of a frame to which a drum unit including the photosensitive drum 410 is attached. FIG. 3 is a cross-sectional view schematically showing a connection structure between the drum unit and the frame. The mounting structure of the photosensitive drum 410 will be described with reference to FIGS. 1 to 3.

  The main housing 110 includes a conductive frame 710. The frame 710 forms an inner wall of the main housing 110. The drum unit 450 includes the photosensitive drum 410 described above. The drum unit 450 is attached to the frame 710. The frame 710 includes a substantially rectangular main plate 711 and a side plate 712 that protrudes from the periphery of the main plate 711 in the direction opposite to the drum unit 450. The main plate 711 includes a first surface 713 facing the drum unit 450 and a second surface 714 opposite to the first surface 713. The drum unit 450 is disposed on the first surface 713 side.

  The photosensitive drum 410 includes a rotating shaft 420. The rotating shaft 420 passes through the main plate 711 and protrudes from the second surface 714. The copying machine 100 further includes a drive mechanism 800 formed to transmit a driving force to the rotary shaft 420. The drive mechanism 800 is attached to the second surface 714 of the main plate 711.

  FIG. 4 is a perspective view of the frame 710. The frame 710 is described with reference to FIGS.

  A through hole 715 into which the rotation shaft 420 of the photosensitive drum 410 is inserted is formed in the main plate 711 of the frame 710. The main plate 711 is provided with a large number of openings in addition to the through holes 715. These openings are used for mounting or driving various devices (for example, various devices described with reference to FIG. 1) disposed in the lower casing 111 of the copying machine 100.

  FIG. 5 is a perspective view of the drive mechanism 800 viewed from the main plate 711 side. FIG. 6 is a perspective view of the drive mechanism 800 viewed from the side opposite to FIG. The drive mechanism 800 will be described with reference to FIGS.

  The drive mechanism 800 includes a motor 810 that is used as a drive source for generating a driving force on the rotating shaft 420 of the photosensitive drum 410, and a transmission unit (described later) that transmits the driving force from the motor 810 to the rotating shaft 420 of the photosensitive drum 410. And a housing 820 for accommodating the transmission unit. The housing 820 includes a first outer shell body 821 and a second outer shell body 822. The first outer shell 821 is disposed between the main plate 711 of the frame 710 and the second outer shell 822. The first outer shell body 821 and the second outer shell body 822 overlap to form an internal space for accommodating the transmission unit. The motor 810 is attached to the outer surface of the second outer shell 822. The shaft of the motor 810 is inserted into an internal space formed by the first outer shell body 821 and the second outer shell body 822, and transmits a driving force to the transmission unit.

  FIG. 7 is a perspective view of the frame 710 to which the drive mechanism 800 is attached. The attachment of the drive mechanism 800 to the frame 710 will be described with reference to FIGS. 1, 2, 4, 5, and 7.

  The drive mechanism 800 includes a plurality of gears and shafts exposed from the outer surface of the first outer shell body 821. The lowermost gear 831 among the plurality of gears and shafts is used to drive a paper feed roller 316 for feeding the sheet S from the manual feed tray 220 into the lower housing 111. A paper feed roller 312 for feeding the sheet S from the cassette 210 is connected to the rotation shaft 832 obliquely above the gear 831. A gear 833 disposed above the rotation shaft 832 is used to drive a registration roller pair 318 disposed upstream of the image forming unit 400. A gear 834 located obliquely above and to the left of the gear 833 is used for driving the developing device 414. A gear 835 disposed on the right side of the gear 834 is used to drive a conveyance roller pair 321 disposed on the downstream side of the return conveyance path 319. The first outer shell 821 includes a substantially cylindrical positioning cylinder 823 located above the gears 834 and 835. As shown in FIG. 3, the rotating shaft 420 of the photosensitive drum 410 is inserted into the positioning cylinder 823. A gear 836 located above the positioning cylinder 823 is used to drive the heating roller 510.

  As shown in FIG. 4, in addition to the above-described through hole 715, the main plate 711 exposes a through hole 716 for projecting the gear 831 to the first surface 713 side and a rotating shaft 832 to the first surface 713 side. Through hole 717 for projecting gear 833 to the first surface 713 side, through hole 718 for projecting gear 834 to the first surface 713 side, and gear 835 projecting to the first surface 713 side A through hole 720 and a through hole 721 for projecting the gear 836 toward the first surface 713 are formed. The positioning cylinder 823 formed so as to protrude from the outer surface of the first outer shell 821 passes through the main plate 711 through the through hole 715 and protrudes toward the first surface 713.

  FIG. 8 is a perspective view showing the internal structure of the second outer shell 822. FIG. 9 is a perspective view of the transmission unit constructed on the inner surface side of the second outer shell 822. The second outer shell body 822 and the transmission unit will be described with reference to FIGS. 5, 8, and 9.

  The second outer shell 822 includes a shaft 824 that supports the gear 831, a space 825 that houses the gear 837 for rotating the rotating shaft 832, and a space that houses the gear 838 for transmitting the driving force to the gear 833. 826, a shaft 827 supporting the gear 834, a shaft 828 supporting the gear 835, and a shaft 829 supporting the gear 836. The second outer shell 822 includes a space for supporting or accommodating a large number of gears for transmitting a driving force to these gears in addition to the shaft and the space. The transmission unit 830 includes a plurality of gears attached to the second outer shell body 822. The transmission unit 830 includes a main gear 850 having the largest diameter among a plurality of gears attached to the second outer shell 822. Further, the second outer shell includes a partition wall 859 that forms a space for accommodating the main gear 850. In the present embodiment, the main gear 850 is exemplified as a relay gear.

  10 and 11 are perspective views of a support plate used for connecting the motor 810 to the outer surface of the second outer shell 822. FIG. FIG. 10 is a perspective view of the support plate viewed from the outer surface side to which the motor 810 is connected. FIG. 11 is a perspective view of the support plate as viewed from the side facing the second outer shell body 822. The support plate will be described with reference to FIGS. 3, 6, and 8 to 11.

  The drive mechanism 800 further includes a conductive support plate 860 for supporting the motor 810. The motor 810 is attached to the outer surface of the second outer shell 822 via the support plate 860. The support plate 860 is made of, for example, a metal plate material, and not only supports the motor 810 but also improves the rigidity of the second outer shell 822. The shaft 811 of the motor 810 passes through the support plate 860. A drive gear 812 is attached to the tip of the shaft 811 of the motor 810. The shaft 811 of the motor 810 further passes through the second outer shell 822 and is connected to the transmission unit 830. The drive gear 812 meshes with a main gear 850 and a gear 839 for transmitting a driving force to the gear 899. Thus, the driving force of the motor 810 is transmitted to the transmission unit 830.

  A substantially cylindrical support cylinder 861 is caulked and attached to the support plate 860. The support cylinder 861 penetrates the second outer shell 822 and supports the main gear 850 in a rotatable manner.

  As shown in FIG. 3, the rotating shaft 420 of the photosensitive drum 410 is inserted into the housing 820 through the positioning cylinder 823. The distal end portion of the rotation shaft 420 is inserted into a support cylinder 861 that protrudes within the housing 820 and is rotatably supported by the support cylinder 861. Thus, the drive mechanism 800 is positioned with reference to the rotation shaft 420 of the photosensitive drum 410. A cylindrical portion 851 formed at the center of the main gear 850 is rotatably supported by the support cylinder 861. The edge of the cylindrical portion 851 on the first outer shell 821 side is processed into a wave shape. A coupling 852 arranged coaxially with the cylindrical portion 851 is connected to the main gear 850 and the rotating shaft 420. The end of the coupling 852 is complementary to the end of the cylindrical portion 851, and the engagement between the end of the coupling 852 and the end of the cylindrical portion 851 causes the main gear 850 to move to the rotating shaft 420 and the motor 810. The driving force is transmitted.

Second Embodiment
FIG. 12 is a perspective view of a driving device used in the image forming apparatus according to the second embodiment. The same code | symbol is assigned with respect to the element similar to 1st Embodiment. Differences from the first embodiment will be described with reference to FIGS. 1 to 3 and FIGS. 11 and 12. In addition, the description which concerns on 1st Embodiment is used suitably with respect to the element which is not demonstrated below.

  A copying machine 100A according to the second embodiment includes a drive mechanism 800A. The structure of the drive mechanism 800A is different from that of the copier 100 according to the first embodiment. In the second embodiment, the copying machine 100A is exemplified as an image forming apparatus.

  The drive mechanism 800A includes a motor 810 that is used as a drive source for generating a driving force on the rotating shaft 420 of the photosensitive drum 410, a transmission unit 830 that transmits the driving force from the motor 810 to the rotating shaft 420 of the photosensitive drum 410, A housing 820 </ b> A for accommodating the transmission unit 830. The housing 820A includes a first outer shell body 821 and a second outer shell body 822A. The first outer shell body 821 is disposed between the main plate 711 of the frame 710 and the second outer shell body 822A. The first outer shell body 821 and the second outer shell body 822 </ b> A overlap to form an internal space for accommodating the transmission unit 830. The motor 810 is attached to the outer surface of the second outer shell 822A. The shaft 811 of the motor 810 is inserted into an internal space formed by the first outer shell body 821 and the second outer shell body 822 </ b> A, and transmits driving force to the transmission unit 830.

  The drive mechanism 800A further includes a support plate 860 for supporting the motor 810. The motor 810 is attached to the outer surface of the second outer shell body 822A via the support plate 860. The support plate 860 is made of, for example, a metal plate, and not only supports the motor 810 but also improves the rigidity of the second outer shell 822A. The shaft 811 of the motor 810 passes through the support plate 860. A drive gear 812 is attached to the tip of the shaft 811 of the motor 810. The shaft 811 of the motor 810 further passes through the second outer shell 822A and is connected to the transmission unit 830. The drive gear 812 meshes with a main gear 850 and a gear 839 for transmitting a driving force to the gear 899. Thus, the driving force of the motor 810 is transmitted to the transmission unit 830.

  The drive mechanism 800A further includes a conductive ground wire 870. The ground wire 870 performs grounding for the electric power supplied to the motor 810. Similar to the first embodiment, the main plate 711 and the support plate 860 of the frame 710 are formed of a conductive material (for example, a metal plate). The ground wire 870 is connected to the main plate 711 and the support plate 860. In the present embodiment, the ground wire 870 is exemplified as a ground element.

  FIG. 13 is an enlarged perspective view around the ground wire 870. Note that the support plate 860 and the motor 810 are removed from the driving device 800A shown in FIG. The drive mechanism 800A will be further described with reference to FIGS.

  The drive mechanism 800A includes a plurality of screws 871 for attaching the support plate 860 to the second outer shell 822A. As shown in FIG. 13, the second outer shell 822A is formed with a receiving hole 872. The accommodation hole 872 is formed on a line connecting a pair of screws 871 that press the edge (the right edge in FIG. 12) of the support plate 860.

  The second outer shell 822A includes a protruding portion 873 that protrudes upward. The ground wire 870 includes a first end 874 partially embedded in the accommodation hole 872 and a second end 875 held between the protrusion 873 and the main plate 711.

  FIG. 14 is a perspective view of the ground wire 870. The ground wire 870 is described with reference to FIGS.

  The first end 874 and the second end 875 of the ground wire 870 are each formed in a coil shape. The first end 874 is held by the wall surface of the second outer shell 822A that defines the accommodation hole 872. In the present embodiment, the wall surface of the second outer shell body 822A that defines the accommodation hole 872 is exemplified as the first holding portion.

  As shown in FIG. 13, the second outer shell 822 </ b> A includes a facing surface 878 that faces the support plate 860, and a substantially trapezoidal conical thick portion 876 that protrudes from the facing surface 878. A screw hole 877 that is screwed into the screw 871 is formed in the thick portion 876. The thickness of the thick portion 876 defines the distance between the facing surface 878 and the support plate 860.

  A part of the first end 874 of the ground wire 870 protrudes from the accommodation hole 872. The thickness of the thick portion 876 is determined such that the first end portion 874 protruding from the accommodation hole 872 is compressed by the support plate 860. Therefore, the first end 874 is stably connected to the support plate 860.

  The second end 875 of the ground wire 870 is adjacent to the peripheral surface of the first outer shell 821. The protruding portion 873 of the second outer shell body 822A includes, for example, an insertion portion (not shown) that is inserted into the coil-shaped second end portion 875. The second end portion 875 is fitted with the insertion portion, and is appropriately held between the protruding portion 873 and the main plate 711. In the present embodiment, the protruding portion 873 of the second outer shell 822A is exemplified as the second holding portion.

  The second end 875 of the ground wire 870 extends in the thickness direction of the first outer shell 821. The second end 875 of the ground wire 870 is formed longer than the thickness dimension of the first outer shell 821. Accordingly, the second end 875 held by the protrusion 873 of the second outer shell 822A is compressed between the protrusion 873 and the main plate 711 when the drive mechanism 800A is attached to the main plate 711. Therefore, the second end 875 is stably connected to the main plate 711.

  The present invention is suitably applied to an image forming apparatus that forms a toner image using an image carrier.

100, 100A ... Copier (image forming apparatus)
410... Photoconductor drum (image carrier)
420... Rotating shaft 711 ... Main plate 713 ... First surface 714 ... Second surface 800, 800A ...・ Drive mechanism 810 ・ ・ ・ ・ ・ ・ ・ ・ Motor (drive source)
812..., Drive gears 820, 820 A .. casing 823... Positioning cylinder 830. Main gear (relay gear)
852 ... Coupling 860 ... Support plate 861 ... Support cylinder 870 ... Ground wire (ground element)
872 ... Accommodation hole (first holding part)
873 ... Projection (second holding part)
874 ... 1st end 875 ... 2nd end S ... Sheet

Claims (7)

A main plate including a first surface and a second surface opposite to the first surface;
An image carrier disposed on the first surface side and formed to be capable of carrying an image formed on a sheet;
A driving mechanism that is attached to the second surface and includes a transmission unit that transmits a driving force to a rotation shaft of the image carrier,
The drive mechanism includes a positioning cylinder that penetrates the main plate from the second surface toward the first surface;
The image forming apparatus, wherein the transmission unit is connected to the rotating shaft inserted into the positioning cylinder. The drive mechanism includes a housing that houses the transmission unit,
The image forming apparatus according to claim 1, wherein the positioning cylinder is formed in the housing. A driving source for generating the driving force;
A support plate attached to the outer surface of the housing and supporting the drive source;
The image forming apparatus according to claim 2, wherein the support plate includes a support cylinder that rotatably supports the rotating shaft inserted into the housing through the positioning cylinder. The drive source includes a motor,
The transmission unit includes a drive gear connected to the shaft of the motor;
A relay gear that meshes with the drive gear and is rotatably supported by the support cylinder;
The image forming apparatus according to claim 3, further comprising a coupling that connects the relay gear and the rotating shaft. The drive mechanism includes a conductive ground element including a first end connected to the support plate and a second end connected to the main plate,
The image forming apparatus according to claim 4, wherein the main plate and the support plate have conductivity. The housing includes a first holding portion that holds the first end,
The first end held by the first holding part is wound in a coil shape,
The image forming apparatus according to claim 5, wherein the support plate compresses the first end portion. The housing includes a second holding portion that holds the second end,
The image forming apparatus according to claim 5, wherein the second end portion wound in a coil shape is compressed between the second holding portion and the main plate.

Images