JP6112840B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic image forming apparatus such as a laser beam printer or a copying machine.

  In the image forming apparatus, there is a configuration in which a part of the image forming apparatus can be easily attached and detached as a detachable unit with respect to the apparatus body to facilitate maintenance and component replacement. In Patent Document 1, as a configuration for fixing the detachable unit to the apparatus main body, a lock member provided in the detachable unit is swung in a direction crossing the mounting direction of the detachable unit to be engaged with or engaged with the apparatus main body. A configuration to be released is disclosed.

JP 2007-199613 A

  However, in the configuration of Patent Document 1, the lock member is urged vertically downward by its own weight and is not fixed. For this reason, when a large impact or vibration is applied to the detachable unit, the lock member moves, the engagement with the apparatus main body is released, and the fixing of the detachable unit may be released.

  In view of the above problems, an object of the present invention is to more firmly fix the detachable unit to the apparatus main body.

  The present invention includes a device frame, a detachable unit that can be attached to and detached from the device main body, a fixing member that presses the detachable unit against the abutting portion of the frame, and fixes the detachable unit; In an image forming apparatus for forming an image on a recording material in a state where the detachable unit is fixed to the frame body, the fixing member presses the detachable unit against the abutting portion of the frame body And a restricting member for restricting movement of the fixing member.

  According to the present invention, the detachable unit can be more firmly fixed to the apparatus main body.

The figure which shows a belt unit and a locking member. 1 is a schematic sectional view of an image forming apparatus. The perspective view of a belt unit. (A) A view of the vicinity of the downstream side of the belt unit in the B direction when the belt unit is mounted on the stay, as viewed from the direction opposite to the A direction. (B) B direction of the belt unit when the belt unit is mounted on the stay. The figure which looked at the downstream part vicinity from the B direction. (A) A view of the vicinity of the portion on the downstream side in the B direction of the belt unit attached to the stay as viewed from the opposite direction to the A direction, (b) a portion of the belt unit attached to the stay on the downstream side in the B direction in the B direction. Figure seen from. FIG. 3 is a schematic cross-sectional view illustrating a state where the belt unit is detached from the image forming apparatus main body.

<First Embodiment>
An embodiment of the present invention will be described. In the following description, when the apparatus has a plurality of similar configurations such as the photosensitive drums 1a, 1b, 1c, and 1d, for example, the configuration and the operation thereof will be described as a representative example of the photosensitive drum 1 for simplicity.

[Entire device configuration]
FIG. 2 is a schematic sectional view of the image forming apparatus 100. The image forming apparatus 100 is an electrophotographic tandem laser beam printer that includes an intermediate transfer member 10 and can form a four-color image on a sheet-like recording material such as paper or OHP.

  Hereinafter, the configuration of the image forming apparatus 100 will be described. The image forming apparatus 100 includes a drum-type electrophotographic photosensitive member (hereinafter referred to as “photosensitive drum”) 1 (1a to 1d) for each color. The photosensitive drum 1 is rotatably supported by the image forming apparatus 100 and is rotationally driven in the direction of the arrow R1 by a driving unit (not shown). The following members are arranged around the photosensitive drum 1 along the rotation direction. A developing unit including a charging roller 2 (2a to 2d) for charging the photosensitive drum 1, an exposure unit 30 for irradiating the photosensitive drum 1 with laser light L (La to Ld) based on image information, and a developing roller 6 (6a to 6d). 4. Cleaner unit 5 (5a to 5d) including an intermediate transfer belt (intermediate transfer member) 10 on which a toner image is primarily transferred from the photosensitive drum 1, and a cleaning blade 3 (3a to 3d) for removing toner on the surface of the photosensitive drum 1. Is placed. Each photosensitive drum 1 and each charging roller 2 are pivotally supported by each cleaner unit 5. The cleaner unit 5 and the developing unit 4 corresponding to each other constitute a cartridge 7 (7a to 7d) that is a unit that can be attached to and detached from the apparatus main body 100 integrally. Each cartridge 7 can be attached to and detached from the apparatus main body 100 independently. The cartridges 7 a to 7 d contain toners of different colors (yellow, magenta, cyan, black) in the developing unit 4. As described above, the cartridge 7 integrally includes the photosensitive drum 1 and the charging roller 2, the developing roller 6, and the cleaning blade 3 as process means acting on the photosensitive drum 1. The cartridges 7 a to 7 d can be detached from the apparatus main body by being pulled out in the B direction while being supported by the cartridge tray 82.

  The photosensitive drum 1 is configured by providing a photoconductive layer such as OPC (organic optical semiconductor) on the outer peripheral surface of an aluminum cylinder. The charging roller 2 is composed of a cored bar and a conductive elastic member surrounding the periphery thereof. The charging roller 2 is disposed in contact with the surface of the photosensitive drum 1 and is driven to rotate, and a charging bias is applied by a power source (not shown). The The exposure unit 30 includes a laser light source (not shown) that emits laser light La to Ld, a polygon mirror 31 that reflects the laser light emitted from the laser light source, a mirror 32, and a lens (not shown) that transmits the laser light. ). The exposure unit 30 irradiates the charged photosensitive drum 1 surface with laser light based on image information to form an electrostatic latent image. The developing unit 4 arranges a developing roller 6 at a developing position in contact with the surface of the photosensitive drum 1 so that toner is attached to the electrostatic latent image on the surface of the photosensitive drum 1 to develop the electrostatic latent image. Then, the photosensitive drum 1 is developed to form a toner image on the surface of the photosensitive drum 1.

  The intermediate transfer belt 10 is an endless belt formed so as to form a ring. The intermediate transfer belt 10 is stretched around a driving roller 13, a tension roller 14, and an auxiliary roller 15 as three tension rollers parallel to each other. Yes. The intermediate transfer belt 10 is stretched. When the driving roller 13 is rotated by a driving unit (not shown), the intermediate transfer belt 10 is driven (runs) so that the surface thereof moves in the direction of the arrow R10. At this time, the tension roller 14 and the auxiliary roller are driven to rotate by the intermediate transfer belt 10.

  Further, primary transfer rollers 11 (11a to 11d) are disposed inside the ring of the intermediate transfer belt 10, and the intermediate transfer belt 10 is pressed against the surface of the photosensitive drum 1, so that the photosensitive drum 1 and the intermediate transfer belt 10 are pressed. The primary transfer nip portion N1 (N1a to N1d) is formed therebetween. A primary transfer bias is applied to the primary transfer roller 11 by a power source (not shown). Further, a secondary transfer roller 12 is disposed at a position facing the driving roller 13 on the outer peripheral surface of the intermediate transfer belt 10, and a secondary transfer nip portion N <b> 2 is formed between the intermediate transfer belt 10 and the intermediate transfer belt 10. . A secondary transfer bias is applied to the secondary transfer roller 12 by a power source (not shown).

  Further, with respect to the moving direction of the surface of the intermediate transfer belt 10, a roller charger 51 facing the outer peripheral surface of the intermediate transfer belt 10 is provided downstream of the secondary transfer nip portion N2 and upstream of the primary transfer nip portion N1a. A belt cleaner 50 is provided.

  The paper feed unit 40 feeds the recording material P to the secondary transfer nip portion N2, and includes a paper feed cassette 41 that stores a plurality of recording materials P, a supply roller 42, a registration roller 43, and the like. Yes.

  With respect to the conveyance direction (arrow K direction) of the recording material P, a fixing device 20 is provided on the downstream side of the secondary transfer nip portion N2 to heat and press the recording material P to fix the toner on the recording material P. It has been.

(Image forming operation)
Next, an image forming operation of the image forming apparatus 100 will be described. As the photosensitive drum 1 is driven to rotate in the direction of arrow R1, a toner image is formed on the surface through the following steps. First, the surface of the photosensitive drum 1 is charged by contacting the charging roller 2 to which a charging bias is applied, and becomes a predetermined potential. Thereafter, a laser beam L based on the image information is irradiated by the exposure unit 30, and an electrostatic latent image is formed on the surface. The electrostatic latent image on the surface of the photosensitive drum is a toner image in which the electrostatic latent image is developed by attaching toner to a portion irradiated with laser light at a position facing (contacting) the developing roller 6. . By performing such an operation on each photosensitive drum 1, toner images of different colors (yellow, magenta, cyan, black) are formed on each photosensitive drum.

  The toner image on the photosensitive drum 1 is transferred onto the intermediate transfer belt 10 in contact with the photosensitive drum 1 at the primary transfer nip N <b> 1 by the action of the primary transfer bias applied to the primary transfer roller 11. Further, the toner images on the respective photosensitive drums 1 are formed at a timing such that they overlap each other when transferred onto the intermediate transfer belt 10. Therefore, a four-color toner image in which yellow, magenta, cyan, and black toner images overlap is formed on the intermediate transfer belt 10. The toner remaining on the photosensitive drum 1 after passing through the primary transfer nip N1 is scraped off by the cleaning blade 3 of the cleaner unit 5.

  The toner image on the intermediate transfer belt 10 is conveyed to the secondary transfer nip portion N2 by the rotation of the intermediate transfer belt 10. The toner image on the intermediate transfer belt 10 is conveyed to the secondary transfer nip portion N2 at the timing of the secondary transfer nip portion N2 by the action of the secondary transfer bias applied to the secondary transfer roller 12. Transferred onto P.

  The recording material P onto which the toner image has been transferred is conveyed to the fixing device 20, where it is heated and pressurized, and the toner image is fixed (melted and fixed) to the recording material P. As a result, four color images are formed on the recording material P. Then, the recording material P that has passed through the fixing device 20 is discharged out of the apparatus main body 100 by the discharge roller 61.

  The toner remaining on the surface of the intermediate transfer belt 10 after passing through the secondary transfer nip N2 is reversed in polarity by the roller charger 51 of the belt cleaner 50 and transferred onto the photosensitive drum 1 at the primary transfer nip N1, and the cleaner unit. 5 is scraped off.

[Frame structure in the device]
The apparatus main body 100 includes a right side plate and a left side plate (not shown) as frame bodies. The right side plate and the left side plate are plate-like metal members parallel to the surface orthogonal to the axial direction of the photosensitive drum 1, and the cartridges 7 a to 7 d in the apparatus main body 100 and the intermediate transfer belt with respect to the axial direction of the photosensitive drum 1. 10 are arranged opposite to each other with 10 therebetween. A stay 85 (see FIG. 6) is fixed between the right side plate and the left side plate.

[Belt unit]
Next, the belt unit 90 including the intermediate transfer belt 10 will be described. FIG. 3 is a perspective view of the belt unit 90. The belt unit 90 includes a pair of two belt unit side plates (frame side plates) 91 (91L, 91R) provided as frames of the belt unit 90 at both ends of the intermediate transfer belt 10 with respect to the axial direction of the photosensitive drum 1. The two belt unit side plates 91 pivotally support the drive roller 13, the tension roller 14, and the auxiliary roller 15 in a rotatable manner. The two belt unit side plates 91 pivotally support the primary transfer rollers 11a to 11d via bearings (not shown). Note that the rotation axes of the drive roller 13, the tension roller 14, and the auxiliary roller 15 are parallel to the axial direction of the photosensitive drum 1. The belt unit 90 attached to the apparatus main body 100 determines the positions of the photosensitive drums 1a to 1d of the cartridges 7a to 7d in the apparatus main body 100. For this reason, the belt unit side plates 91L and 91R each include a positioning portion 91b against which the bearings of the photosensitive drums 1a to 1d of the cartridges 7a to 7d move and vertically abut. The positioning portion 91b has a plurality of V-shaped groove shapes corresponding to the respective cartridges 7, and each of the photosensitive drums 1a to 1d has a position in the arrangement direction (B direction) of the photosensitive drums 1 and a vertical direction. Determine the position. Further, the belt unit 91 is configured to be able to support lock members 93L and 93R, which will be described later, on the downstream side of the belt unit 91 in the B direction.

  FIG. 6 is a schematic cross-sectional view showing a state where the belt unit 90 is detached from the apparatus main body 100. As described above, the belt unit 90 is a detachable unit that is detachable from the apparatus main body 100. When attaching the belt unit 90 to the apparatus main body 100, the belt unit 90 is inserted into the apparatus main body 100 in the direction B parallel to the photosensitive drums 1a to 1d (see FIG. 2) from the rear side to the front side of the apparatus main body 100. What is necessary is just to fix by the lock mechanism mentioned later. When removing the belt unit 90, the fixing by a lock mechanism, which will be described later, is released, and the belt unit 90 may be pulled out in the direction from the front side of the apparatus toward the rear side (the opposite direction to the B direction).

  Each of the two belt unit side plates 91L and 91R is provided with positioning portions 91a at the upstream and downstream portions in the B direction. Of the total four positioning portions 91a provided in the belt unit side plates 91L and 91R, the two positioning portions 91a on the upstream side in the B direction are inserted into the two positioning holes 85a provided in the stay 85 to be positioned in the positioning holes 85a. The position of the belt unit 90 with respect to that direction is determined by restricting the position of the edge of the belt unit 90 in the A direction parallel to the rotation axis of the photosensitive drum 1. The two positioning portions 91a on the downstream side in the B direction provided on the belt unit side plates 91L and 91R abut against a positioning abutting portion 85d (see FIG. 5A) provided on a stay 85 described later, and the position in the B direction is set. By being regulated, the position of the belt unit 90 in that direction is determined.

[Configuration of locking mechanism]
Next, the lock mechanism of the belt unit 90 will be described. FIG. 1 is a diagram showing a belt unit 90 included in the lock mechanism and a lock member 93 as a fixing member for locking (fixing) the belt unit 90. In the following description of the embodiment, the configuration on the belt unit side plate 91R side will be described as a representative, but the belt unit side plate 91L side has the same configuration.

  A fastening portion (hole) 91cR that is fastened to the positioning portion 91aR and the stay 85 described above is provided at the end of the belt unit side plate 91R on the downstream side in the B direction, and rotatably supports the lock member 93R. The lock member 93R is provided with a holding portion 93aR, a fixing portion 93bR, a fastening portion 93cR, and a wedge portion 93dR. The holding portion 93aR is a second pressing portion, and is a contact portion with the belt unit side plate 91R that is in contact with the lock member 93R when it rotates. The fixing portion 93bR is a first pressing portion, and is a portion where the lock member 93R hits the stay 85 when the belt unit 90 is fixed to the stay 85. The wedge portion 93dR is provided between the holding portion 93aR and the fixing portion 93bR and is inserted between the belt unit side plate 91R and the stay 85. The fastening portion (hole) 93cR is a portion that overlaps with the fastening portion (hole) 91cR of the belt unit side plate 91R and is screwed and fixed to the stay 85 by inserting screws 87 as fastening members together.

[How to install the belt unit 90]
Next, a method for attaching the belt unit 90 to the stay 85 of the apparatus main body 100 will be described. FIG. 4 is a view showing the vicinity of a part of the belt unit 90 on the downstream side in the B direction when the belt unit 90 is moved in the B direction and attached to the stay 85, and (a) is viewed from the direction opposite to the A direction. FIG. 4B is a diagram viewed from the B direction. FIGS. 5A and 5B are views showing the vicinity of the portion on the downstream side in the B direction of the belt unit 90 attached to the stay 85. FIG. 5A is a view seen from the direction opposite to the A direction, and FIG. FIG.

  In the state shown in FIG. 4, when the belt unit 90 is inserted in the apparatus body 100 in the B direction and moved on the stay 85 in the B direction, the wedge portion 93 dR of the lock member 93 </ b> R is on the upper surface of the stay 85. It is. In this state, the frame fastening portion (hole) 91cR and the fastening portion (hole) 93c of the lock member 93R are displaced, and screws are inserted into the frame fastening portion (hole) 91cR and the fastening portion (hole) 93c of the lock member 93R. The stay 85 cannot be concluded.

  When the belt unit 90 is further inserted in the B direction, the positioning portion 91aR of the belt unit 90 abuts in the B direction on the abutting portion 85d for the belt unit side plate 91R provided on the stay 85 as shown in FIG. The lock member 93R rotates around the holding portion 93a and falls into the hole of the stay 85 by its own weight, the wedge portion 93dR is inserted between the belt unit side plate 91R and the stay 85, and the fixing portion 93b is locked to the stay 85. It abuts against the abutment portion 85c for the member 93R. As a result, the frame fastening portion (hole) 91cR and the fastening portion (hole) 93cR of the lock member 93R overlap each other and the positions thereof coincide with each other, and the screw 87 is inserted in the B direction and fastened to the fastening portion (hole) 85b of the stay 85. It becomes possible to do. Here, the line L1 connecting the holding portion 93aR and the fixing portion 93bR of the lock member 93R intersects the line L2 indicating the fastening direction parallel to the B direction. For this reason, at the time of fastening with the screw 87, the lock member 93R is pressed in the substantially B direction by the screw 87, thereby pressing the belt unit side plate 91R in the substantially B direction at the end of the holding portion 93aR. The fixing portion 93bR rotates around the 93aR in a direction in which the fixing portion 93bR contacts and presses against the abutting portion 85c. For this reason, the movement of the lock member 93R is restricted by the screw 87 which is a restriction member, and the belt unit 90 is firmly fixed.

  In particular, as in this embodiment, when the position of the cartridge 7 is determined by the positioning portions 91b of the belt unit side plates 91L and 91R, it is necessary to position the belt unit 90 itself more firmly. In other words, when the cartridge 7 is replaced, the cartridge 7 hits the belt unit side plates 91L and 91R, and an impact is applied to the belt unit 90. Further, the developing roller 6 can move between a contact position where the developing roller 6 is in contact with the photosensitive drum 1 and a retracted position separated from the photosensitive drum 1, and the developing roller 6 is moved from the retracted position to the contact position and is moved to the photosensitive drum. 1 is transmitted to the belt unit side plates 91L and 91R via the photosensitive drum 1. Since the belt unit 90 positions the cartridge 7 in the apparatus main body 100 as described above, the belt unit 90 is fixed from the cartridge 7 by firmly fixing the belt unit 90 to the stay 85 as in the present embodiment. Can withstand the impact force.

  As described above, the positioning of the belt unit 90 in the B direction is performed by the abutting portion 85d, and the end of the holding portion 93a of the lock member 93 is substantially in the B direction by fastening with the screw 87. Press. Accordingly, the belt unit side plate 91 firmly hits the abutting portion 85d, and the belt unit 90 is firmly fixed to the stay 85. Even when a force is applied to the belt unit 90 in the direction of taking out from the apparatus main body 100 (the direction opposite to the B direction), the belt unit side plate 91 abuts against the holding portion 93a of the lock member 93, and the lock member 93 is also The fixing part 93b is fixed by abutting against the abutting part 85c. With such a configuration, the belt unit 90 is firmly fixed to the stay 85 with no play in both the B direction as the mounting direction and the opposite direction to the B direction as the removal direction. Further, if the amount of insertion in the B direction into the apparatus main body 100 is insufficient when the belt unit 90 is mounted, the fastening portion 93c of the lock member 93 does not come to a position where it can be fastened with the screw 87, thereby preventing erroneous mounting. it can. Further, since the insertion direction (direction B) of the screw is parallel or substantially parallel to the insertion direction of the belt unit 90 to the apparatus main body 100, the insertion or removal operation of the belt unit 90 and the fastening or unfastening operation of the screw 87 are performed. Can be performed quickly and continuously, and workability is good.

<Other embodiments>
In the first embodiment, the image forming apparatus using the intermediate transfer belt 10 has been described. However, an electrostatic conveyance belt (ETB) may be used instead of the intermediate transfer belt 10. In this case, the belt unit 90 includes an electrostatic conveyance belt, a plurality of rollers on which the electrostatic conveyance belt is stretched, and a frame that pivotally supports the plurality of rollers, and the frame is fixed by a lock member 93. Also good. In the first embodiment, the cartridge 7 includes the photosensitive drum 1 and the process means acting on the photosensitive drum 1. However, the cartridge 7 includes only the developing unit 4 and the cartridge tray 82 includes the photosensitive drum 1. It may be.

  Further, the detachable member fixed by the lock member 93 may be a unit other than the belt unit detachable from the apparatus main body 100. For example, a fixing unit including the fixing device 20, a power supply unit that supplies power to the apparatus main body, and a duplex printing unit including a recording material conveying unit for duplex printing may be used.

DESCRIPTION OF SYMBOLS 1 Photosensitive drum 10 Intermediate transfer belt 85 Stay 85d Abutting part 87 Screw 90 Belt unit 91 Belt unit side plate 91a Positioning part 91c Fastening part 93 Lock member 93a Holding part 93b Fastening part 93c Fastening part 93d Wedge part

Claims (8)

Has a frame of the apparatus main body, a detachable unit detachably mountable to the apparatus main body, and a fixing member pressing and fixing the detachable unit abutted against said detachable unit to the abutting portion of the frame, the In the image forming apparatus for forming an image on a recording material in a state where the detachable unit is fixed to the frame body,
Have a regulating member for regulating the movement of the fixing member in a state in which the fixing member presses abutted against said detachable unit to the abutting portions of the frame,
The fixing member includes a first pressing portion that presses the frame body, a second pressing portion that presses the detachable unit, and a wedge portion provided between the first pressing portion and the second pressing portion. an image forming apparatus comprising: a. The image forming apparatus according to claim 1, wherein the fixing member is rotatably supported by the detachable unit.   The direction in which the restricting member presses the fixing member is a direction in which the fixing member is moved so that a width between the first pressing portion and the second pressing portion of the wedge portion is widened. The image forming apparatus according to claim 2.   The fixing member and the frame body are provided with holes at positions facing each other, and the restricting member is inserted into the hole provided in the fixing member and the frame body, whereby the fixing member and the frame body are The detachable unit is mounted by being inserted into the apparatus main body, and is provided in the insertion direction of the detachable unit into the apparatus main body, the fixing member of the fastening member, and the frame body. 4. The image forming apparatus according to claim 1, wherein the insertion direction of the holes is parallel or substantially parallel. 5.   5. The image forming apparatus according to claim 1, further comprising: a photosensitive drum, wherein the attachment / detachment unit includes a belt that contacts the photosensitive drum supported by the frame body.   6. The image forming apparatus according to claim 5, further comprising: a cartridge including the photosensitive drum, wherein the attachment / detachment unit includes a positioning unit that determines a position of the cartridge in the apparatus main body when the cartridge comes into contact with the cartridge. The image forming apparatus according to claim 5, wherein the detachable unit includes an intermediate transfer belt on which a toner image is primarily transferred from the photosensitive drum as the belt. The image forming apparatus according to claim 4, wherein an insertion direction of the insertion member intersects with a virtual line connecting the first pressing portion and the second pressing portion.

Images