JP6304052B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including a transport device that transports paper.

  In image forming apparatuses such as printers and copiers, transport devices such as a pair of transport rollers and a pair of discharge rollers are arranged on the transport path through which paper is transported, and the paper is transported along the transport path in response to image forming operations. Is done. Such a conveying device has a driving roller that is rotationally driven and a driven roller that is driven to rotate while being pressed against the driving roller, and a sheet is sandwiched between the two rollers and conveyed in a predetermined direction.

  The driven roller is often supported by a support member using a stop ring such as an E ring or a C ring. However, when such a stop ring is used, when the number of driven rollers increases, there is a problem that it takes time for the mounting operation or costs increase. In addition, when the cross-sectional shape of the support shaft of the driven roller is circular, the support shaft may rotate together with the drive roller, causing problems such as abnormal noise.

  Therefore, Patent Document 1 discloses a transport device in which a notch into which an end of a support shaft of a driven roller is inserted is formed in a support member. The notch is provided with a narrow portion to prevent the spindle inserted in the notch from coming off, and the end of the spindle is brought into contact with the narrow portion by a leaf spring. The shaft is prevented from rotating.

JP 7-48047 A

  However, in the roller device described in Patent Document 1, since it is necessary to form a notch in the support member so as to correspond to both ends of the driven roller, a relatively wide space is required to install the driven roller. become. Further, since the driven roller is positioned at a position where the support shaft contacts the narrow portion, it is difficult to adjust the pressure contact force with respect to the driving roller.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an image forming apparatus including a conveying device that can prevent a driven roller from rotating by a simple mechanism in consideration of the above circumstances.

  In order to achieve the above object, an image forming apparatus of the present invention includes a driving roller that is rotationally driven, a driven roller that rotates as the driving roller rotates, and a support member that supports the driven roller. The driven roller has a support shaft and a rotating body that is rotatably supported by the support shaft, and a locking portion formed by bending a part of the support shaft is integrally provided, The supporting shaft is prevented from rotating by locking the locking portion to the support member.

  By adopting such a configuration, the driven roller can be prevented from rotating with a simple configuration that does not use a separate member.

  In the image forming apparatus of the present invention, the support member is formed with a recess into which the locking portion is inserted, and the support shaft is prevented from rotating by inserting the locking portion into the recess. In addition, the movement of the support shaft in the axial direction may be restricted.

  By employ | adopting such a structure, a latching | locking part can be reliably latched to a support member.

  In the image forming apparatus according to the aspect of the invention, the locking portion may be formed by bending one end portion of the support shaft in an L shape.

  By employ | adopting such a structure, a latching | locking part can be formed easily.

  In the image forming apparatus according to the aspect of the invention, the locking portion may be formed by bending a part of the support shaft into a U shape.

  By employ | adopting such a structure, a latching | locking part can also be formed in the middle of a spindle, and a driven roller can be supported by parts other than both ends.

  In the image forming apparatus according to the aspect of the invention, the support member may include a grip portion that supports the driven roller at a portion other than the locking portion.

  By adopting such a configuration, the driven roller can be stably supported.

  In the image forming apparatus of the present invention, the concave portion and the bearing portion may be opened upward, and the driven roller may be detachable from the upper side with respect to the support member.

  By adopting such a configuration, the driven roller can be easily attached and detached.

  According to the present invention, the driven roller can be prevented from rotating with a simple mechanism, and the movement of the support shaft in the axial direction can be restricted.

1 is a schematic diagram illustrating an outline of a configuration of a printer according to an embodiment of the present invention. FIG. 3 is a front cross-sectional view showing the periphery of the fixing device and the paper discharge device in the printer according to the embodiment of the present invention. It is a side view of the paper discharge device concerning one embodiment of the present invention. 4A is a cross-sectional view taken along line AA in FIG. 3, and FIG. 4B is a cross-sectional view taken along line BB in FIG. It is a side view which shows the modification of the driven roller in the paper discharge apparatus which concerns on one Embodiment of this invention.

  Hereinafter, an image forming apparatus according to an embodiment of the present disclosure will be described with reference to the drawings.

  First, an overall configuration of a printer 1 as an image forming apparatus will be described with reference to FIG. FIG. 1 is a schematic diagram showing an outline of a printer according to an embodiment of the present invention. In the following description, the front side of the page in FIG. 1 is the front side (front side) of the printer 1, and the left and right directions are the printer. The direction when 1 is viewed from the front is used as a reference.

  The printer 1 includes a substantially rectangular parallelepiped housing 2 having a hollow portion. A paper discharge tray 3 is provided on the upper surface of the housing 2. A paper feed cassette 4 is housed below the hollow portion of the housing 2, and a paper feed unit 5 that feeds paper from the paper feed cassette 4 is provided at the upper left of the paper feed cassette 4. Above 5, an image forming unit 6 is provided. The image forming unit 6 is rotatably provided with a photosensitive drum 7 as an image carrier. Around the photosensitive drum 7, a charging device 8, a developing device 9, a transfer roller 10, and a cleaning device 11 are provided. Are arranged along the direction of rotation of the photosensitive drum 7 (see arrow X in FIG. 1). The developing device 9 is connected to the toner container 12. An exposure device 13 having a laser scanning unit (LSU) is disposed on the right side of the image forming unit 6. A fixing device 14 is provided above the image forming unit 6, and a paper discharge device 15 (conveying device) facing the paper discharge tray 3 is provided at the upper right of the fixing device 14.

  Further, in the hollow portion, the paper feed unit 5 passes through the transfer unit 16 formed between the photosensitive drum 7 and the transfer roller 10 and the fixing device 14, and extends vertically toward the paper discharge device 15. An extending paper conveyance path 18 is provided. The conveyance path 18 branches to a reverse path 19 downstream of the fixing device 14. The reverse path 19 joins the transport path 18 upstream of the paper feeding unit 5.

  Next, an image forming operation of the printer 1 having such a configuration will be described. First, after the surface of the photosensitive drum 7 is charged by the charging device 8, exposure corresponding to the image data is performed on the photosensitive drum 7 by the laser beam P from the exposure device 13, and the surface of the photosensitive drum 7 is thus obtained. An electrostatic latent image is formed. This electrostatic latent image is developed into a toner image by the developing device 9.

  On the other hand, the paper taken out from the paper feed cassette 4 by the paper feed unit 5 is conveyed to the transfer unit 16 along the conveyance path 18 in synchronism with the above-described image forming operation. The toner image is transferred onto the paper. The sheet on which the toner image has been transferred is conveyed downstream in the conveyance path 18 and enters the fixing device 14. After the toner image is fixed on the sheet in the fixing device 14, the sheet is transferred from the paper discharge device 15 to the paper discharge tray 3. Discharged. When duplex printing is performed, the sheet is conveyed along the reverse path 19 from the downstream side of the fixing device 14. The toner remaining on the photosensitive drum 7 is collected by the cleaning device 11.

  Next, the paper discharge device 15 will be described with reference to FIGS. 2 is a side cross-sectional view of the fixing device and the paper discharge device, FIG. 3 is a view of the paper discharge device as viewed from the right side, FIG. 4A is a cross-sectional view taken along the line AA in FIG. It is BB sectional drawing of.

  The paper discharge device 15 is provided together with the fixing device 14 on a box-shaped fixing frame 20. The fixing device 14 includes a heat roller 44 and a press roller 45 that face each other with the conveyance path 18 interposed therebetween. The fixing frame 20 includes a first frame member 21 (support member) on the right side, a second frame member 22 on the left side, and a cover member 23 that covers the first frame member 21 and the second frame member 22 with the conveyance path 18 in between. And having.

  As shown in FIG. 2, a heat roller 44 is rotatably supported by the first frame member 21 at the lower portion of the left side surface. A lower roller mounting portion 26 extending in the front-rear direction is formed at the upper right corner of the first frame 21. As shown in FIG. 3, three cutout portions 27 are formed on the upper surface of the lower roller mounting portion 26 at a predetermined interval in the front-rear width direction. Furthermore, a recessed portion 28 that is recessed downward is formed at a position closer to the front of the cutout portion 27 formed on the most front side (see also FIG. 4A). The recess 28 is formed in a hole shape having a circular cross-sectional shape.

  Furthermore, on the upper surface of the lower roller mounting portion 26, bearing portions 29 that protrude upward are formed on both sides of the central notch portion 27 in the front-rear direction. As shown in FIG. 4B, each bearing portion 29 has a left piece 31 and a right piece 32 that face in the left-right direction, and a groove 33 is formed between the left and right pieces 31, 32. . Further, a claw portion 34 protruding in the left direction is formed at the tip of the left surface of the right piece 32. Further, as shown in FIG. 3, upwardly projecting bosses 35 are erected on the front side and the rear side in the front-rear direction with respect to each bearing portion 29.

  As shown in FIG. 2, a press roller 45 is rotatably supported by the second frame member 22 at the lower portion of the right side surface. Further, a branch guide 38 is provided at the upper part of the right side surface. The branch guide 38 is provided with a discharge switch 39 that rotates about a fulcrum, and the conveyance path 18 and the reverse path 19 are opened by the discharge switch 39 rotating about the fulcrum.

  The cover member 23 is formed with an upper roller mounting portion 41 facing the lower roller mounting portion 26 of the first frame 21 at the right end of the lower surface so as to extend in the front-rear direction.

  The paper discharge device 15 includes an upper drive roller 51 and a lower driven roller 52 that face each other with the conveyance path 18 in between.

  As shown in FIG. 3, the drive roller 51 includes a support shaft 54 and three roller body portions 55 provided so as to rotate integrally with the support shaft 54. The drive roller 51 is supported by the upper roller mounting portion 41 of the cover member 23 so that the axial direction of the support shaft 54 is the front-rear direction, and the roller main body portion 55 rotates along the transport direction. The support shaft 54 is connected to a drive source (not shown), and rotates in a predetermined direction by a rotational drive force from the drive source.

  The driven roller 52 includes a support shaft 57 and three roller body portions 58 that are rotatably supported by the support shaft 57. A locking portion 60 bent in an L shape is formed at the front end of the support shaft 57.

  The driven roller 52 is supported by the lower roller mounting portion 26 of the first frame member 21 so that the axial direction of the support shaft 57 is the front-rear direction. Each roller body 58 is positioned so as to correspond to each roller body 55 of the driving roller 51 and is accommodated in a notch 27 formed in the lower roller mounting portion 26 of the first frame member 21. Further, the support shaft 57 is inserted into the concave portion 28 and the center portion is fitted into the groove portion 33 of each bearing portion 29 and is prevented by the projection 34. Further, the support shaft 57 is urged upward by a coil spring 62 fitted on each boss 35, so that each roller body 58 is pressed against each roller body 55 of the drive roller 51. The support shaft 57 can also move in the vertical direction between the bottom of the groove 33 and the claw 34 in the groove 33 of each bearing 29. The diameter of the concave portion 28 is a dimension obtained by adding a predetermined gap to the diameter of the locking portion 60. It is the dimension which the front-end | tip of the part 60 does not contact.

  In the paper discharge device 15 having the above configuration, the paper that has passed through the fixing device 14 passes between the driving roller 51 and the driven roller 52 and is discharged onto the paper discharge tray 3. In the driven roller 52, each roller main body 58 is driven to rotate as the paper is transported. Stopping and movement in the axial direction (thrust direction, front-rear direction) are restricted. Each roller body 58 of the driven roller 52 is allowed to move in the axial direction of the support shaft 57 within the range of the width of the roller body 55 of the drive roller 51. Here, the movement of each roller body 58 of the driven roller 52 is restricted within the width of the notch 27 by making the width of the notch 27 narrower than the width of the roller body 55 of the drive roller 51. be able to. Actually, the moving distance of each roller body 58 in the axial direction is about 1 mm.

  As described above, in the driven roller 52 of the present invention, the support shaft 57 can be prevented from rotating with a simple configuration, and the movement in the axial direction can be restricted. Moreover, since the latching | locking part 60 is inserted in the recessed part 28, it is hard to come out, and it can ensure detent | locking and a restriction | limiting of the movement to an axial direction. When the support shaft 57 rotates with the roller body 58, abnormal noise generated by sliding between the support shaft 57 and the bearing portion becomes a problem. However, in the present invention, the support shaft 57 is reliably prevented from rotating. The occurrence of abnormal noise can be prevented. Further, since the support shaft 57 is supported by the bearing portion 29 and pressed against the drive roller 51 by the coil spring 62, it is supported stably. Note that the locking portion 60 does not need to be bent at a substantially right angle with respect to the support shaft 57, but a right angle is preferable because it does not take time and effort for mounting and can reliably restrict movement in the axial direction.

  Further, since the coil spring 62 biases the support shaft 57 upward along the depth direction of the recess 28, the locking portion 60 can freely move in the vertical direction along the recess 28. Can be urged toward the driving roller 51 without resistance, and a predetermined roller nip pressure can be obtained by the urging force of the coil spring 62 set in advance. When the support shaft 57 is linear, the edge of the end is caught on the side surface of the support member, and the roller nip pressure may change, but in this embodiment, the roller nip pressure is stable. The paper can be smoothly conveyed.

  Furthermore, since the upper surface of the recess 28 and the bearing portion 29 is open, the driven roller 52 can be easily attached to and detached from the first frame member 21 from above.

  In addition, although the latching | locking part 60 may be formed in the both ends of the spindle 57, since positioning accuracy with the recessed part 28 is needed, forming in the end of the spindle 57 is preferable. When the locking portions 60 are formed at both ends of the support shaft 57, one of the recesses may be formed in a long hole shape or slit shape that is long in the front-rear direction (the axial direction of the support shaft 57).

  Next, another example of the driven roller 52 will be described with reference to FIG. In the driven roller 52, a locking portion 60 is formed by bending the support shaft 57 in a U shape at a position slightly forward of the center of the support shaft 57. On the other hand, three cutout portions 27 are formed on the upper surface of the lower roller mounting portion 26 of the first frame member 21 at a predetermined interval in the front-rear direction. Furthermore, a downward concave portion 66 is formed on the front side of the central cutout portion 27. The recess 66 is formed in a slit shape extending in the front-rear direction (the axial direction of the support shaft 57). Furthermore, a bearing portion 29 is formed on the upper surface of the lower roller mounting portion 26 on the front side of the recessed portion 66 and on the rear side of the central notch portion 27. A boss 35 is erected on the rear side.

  Also in the driven roller 52, the locking portion 60 is inserted into the recess 66, so that the support shaft 57 is prevented from rotating and movement in the axial direction is restricted. Furthermore, since the latching | locking part 60 is formed in the middle of the spindle 57, the driven roller 52 can be stopped in parts other than both ends. For this reason, the length of the driven roller 52 can be shortened, and the accommodation space of the driven roller 52 can be narrowed. Moreover, the latching | locking part 60 can be formed in the arbitrary positions matched with the shape of the lower roller attaching part 26 of the 1st frame member 21. FIG. The locking part 60 may be V-shaped or U-shaped.

  In the embodiment of the present invention, the case where the driven roller is applied to the paper discharge device 15 has been described. However, the driven roller is provided in the paper conveyance path of the paper conveyance path 18 and the reverse path 19 and the paper conveyance path of the document feeder. The present invention can also be applied to a transport device.

  In the embodiment of the present invention, the case where the configuration of the present invention is applied to the printer 1 has been described. However, in another different embodiment, the image forming apparatus other than the printer 1 such as a copying machine, a facsimile machine, and a multifunction machine is used. A configuration may be applied.

  Furthermore, since the above description of the embodiment of the present invention describes a preferred embodiment of the image forming apparatus according to the present invention, there may be various technically preferable limitations. The technical scope of the present invention is not limited to these embodiments unless specifically described to limit the present invention. That is, the above-described components in the embodiment of the present invention can be appropriately replaced with existing components and the like, and various variations including combinations with other existing components are possible. The description of the embodiment of the present invention described above does not limit the contents of the invention described in the claims.

1 Printer (image forming device)
15 Paper Discharge Device 21 First Frame Member (Support Member)
28 Concave portion 29 Bearing portion 51 Drive roller 52 Followed roller 57 Support shaft 58 Roller body (rotating body)
60 Locking part

Claims (4)

A drive roller that is rotationally driven, a driven roller that rotates as the drive roller rotates, and a support member that supports the driven roller,
The driven roller has a support shaft and a rotating body that is rotatably supported by the support shaft, and a locking portion formed by bending a part of the support shaft is integrally provided, By locking the locking portion to the support member, the support shaft is prevented from rotating,
The image forming apparatus, wherein the locking portion is formed by bending a part of the support shaft into a U shape.   The support member is formed with a recess into which the locking portion is inserted, and when the locking portion is inserted into the recess, the support shaft is prevented from rotating and the axial direction of the support shaft The image forming apparatus according to claim 1, wherein movement of the image forming apparatus is restricted.   The image forming apparatus according to claim 1, wherein a bearing portion that supports the driven roller at a portion other than the locking portion is formed on the support member. The support member is formed with a bearing portion that supports the driven roller at a portion other than the locking portion,
The image forming apparatus according to claim 2 , wherein the concave portion and the bearing portion are opened upward, and the driven roller is detachable from the upper side with respect to the support member.

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