Sheet conveyance device and image forming apparatus

Abstract

To ensure positioning accuracy of a member associated with drive transmission with a simple configuration.SOLUTION: A sheet conveyance device includes a conveyance unit detachably attached to a device body. The conveyance unit includes: a first guide member and a second guide member; a first conveyance roller supported by the first guide member; a second conveyance roller supported by the second guide member; a first drive transmission part provided at a side part of the first guide member; a second drive transmission part provided at a side part of the second guide member; and a cover member covering at least a part of the first drive transmission part and at least a part of the second drive transmission part. A first engaging part of the first guide member and a second engaging part of the second guide member are engaged with a third engaging part and a fourth engaging part of the cover member, thereby the first guide member, the second guide member and the cover member are positioned to each other.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a sheet conveying device for conveying a sheet and an image forming device for forming an image on the sheet.

Background Art

[0002] Image forming apparatuses such as printers, copiers, and multifunction peripherals are provided with a sheet conveying device for forming an image on a sheet while conveying the sheet, which is a recording medium. Further, the image forming apparatus may be provided with a unit that is detachable from the apparatus main body. Patent Document 1 describes an electrophotographic image forming apparatus provided with a detachable developing cartridge. In this developing cartridge, a gear train for driving transmission is provided at an end portion in the longitudinal direction of the cartridge frame, and a side cover is attached to the cartridge frame so as to cover the gear train. Further, by attaching the side cover to the cartridge frame, the side cover is supported by a part of the cartridge frame, and it is described that the deflection of the side cover, which is a member that comes into contact with the apparatus main body when the developing cartridge is mounted, is restricted.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a sheet conveying device, there may be a case where a plurality of rollers and a plurality of drive transmission parts for transmitting a driving force to each of these plurality of rollers are collectively arranged in one conveying unit that is detachable from the apparatus main body. In such a case, if a side cover is arranged for each gear train for driving transmission as described in the above document, the configuration of the conveying unit becomes complicated, leading to an increase in manufacturing cost and an increase in assembly man-hours.

[0005] Therefore, an object of the present invention is to provide a sheet conveying device capable of ensuring the positioning accuracy of members involved in drive transmission with a simple configuration, and an image forming apparatus including the same.

Means for Solving the Problems

[0006] One aspect of the present invention is a sheet conveying device including an apparatus main body and a conveying unit detachably attached to the apparatus main body for conveying a sheet. The conveying unit includes a first guide member within the sheet to be conveyed. proposed A first conveying roller supported by the first guide member for conveying the sheet. and A second conveying roller supported by the second guide member for conveying the sheet, and a first drive transmission unit that transmits a driving force input from the apparatus main body to the first conveying roller on one side in the sheet width direction of the first guide member. a second guide member for guiding the conveyed sheet A second drive transmission unit that transmits a driving force input from the apparatus main body to the second conveying roller on the one side in the sheet width direction of the second guide member, and a cover member that covers at least a part of the first drive transmission unit and at least a part of the second drive transmission unit when viewed from the one side in the sheet width direction. The first guide member has a first fitting portion, the second guide member has a second fitting portion, the cover member has a third fitting portion that fits with the first fitting portion and a fourth fitting portion that fits with the second fitting portion, and the first guide member, the second guide member, and the cover member are positioned relative to each other by fitting the first fitting portion and the third fitting portion and fitting the second fitting portion and the fourth fitting portion. A sheet conveying device characterized by the above. arranged the apparatus main body with a drive source provided from the apparatus main body arranged the apparatus main body with a drive source provided from the apparatus main body equipped with the second guide member has a second fitting portion equipped with the cover member has a third fitting portion that fits with the first fitting portion and a fourth fitting portion that fits with the second fitting portion equipped with the first fitting portion and the third fitting portion are fitted, and the second fitting portion and the fourth fitting portion are fitted, whereby the first guide member, the second guide member, and the cover member are positioned relative to each other. A sheet conveying device characterized by the above.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a sheet conveying device capable of ensuring the positioning accuracy of members involved in drive transmission with a simple configuration, and an image forming apparatus including the same.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings.

[0010] <First Embodiment> FIG. 1 is a schematic diagram of an image forming apparatus 1 according to the first embodiment. The image forming apparatus 1 is an electrophotographic full-color laser printer that forms and outputs an image on a sheet P used as a recording medium based on image information input from an external computer. As the sheet P, various sheet materials with different materials and sizes can be used, such as paper including plain paper and envelopes, glossy paper, plastic films such as overhead projector sheets, and cloth.

[0011] The apparatus main body 100 of the image forming apparatus 1 houses an image forming engine 10 including four image forming units PY, PM, PC, and PK that form yellow, magenta, cyan, and black toner images, and an intermediate transfer belt 21. The image forming units PY to PK have a photosensitive drum 11 that is an image carrier (electrophotographic photosensitive member), and form a toner image on the photosensitive drum 11. The toner image carried on the photosensitive drum 11 is transferred to the sheet P via the intermediate transfer belt 21 that is an intermediate transfer member.

[0012] In the following description and each figure, the Z direction refers to the upward direction along the vertical direction (gravity direction) when the image forming apparatus 1 is installed on a horizontal plane. The Y direction refers to the rotation axis direction of the photosensitive drum 11. The Y direction is the main scanning direction during image formation and is also the sheet width direction perpendicular to the sheet conveyance direction of the sheet conveyed inside the image forming apparatus 1. The Y direction intersects the Z direction and is preferably perpendicular. The X direction refers to the horizontal direction perpendicular to the Y direction.

[0013] The image forming units PY to PK are configured in the same manner except that the colors of the toner used for development are different. Therefore, the image forming unit and the process of forming a toner image (image forming operation) will be described using the yellow image forming unit PY as an example. In addition to the photosensitive drum 11, the image forming unit PY includes a charging roller 12 as a charging means, an exposure device 13Y as an exposure means, a developing device 14 as a developing means, and a drum cleaner. The photosensitive drum 11 is a drum-shaped photoreceptor having a photosensitive layer on its outer peripheral portion, and rotates in a direction (clockwise direction in the figure) along the rotation direction R1 of the intermediate transfer belt 21. The charging roller 12 uniformly charges the surface of the photosensitive drum 11, and the exposure device 13Y irradiates the photosensitive drum 11 with laser light modulated according to a signal (video signal) based on the yellow color component of the image information, and develops the electrostatic latent image on the surface of the photosensitive drum 11 into a toner image.

[0014] The above image forming operations proceed in parallel in each of the image forming units PY to PK. At this time, the exposure devices 13M, 13C, and 13K perform exposure processing based on video signals corresponding to the color components of the respective image information. Then, the developing device 14 performs developing processing with a developer containing toner of each color, so that magenta, cyan, and black toner images are formed on the photosensitive drum 11. The toner images formed on each photosensitive drum 11 are primarily transferred to the intermediate transfer belt 21 by a primary transfer roller 25 which is a primary transfer device. The residual toner remaining on the photosensitive drum 11 after transfer is removed by the drum cleaner.

[0015] The intermediate transfer belt 21 is wound around a secondary transfer inner roller 22, a stretching roller 23, a tension roller 24, and a primary transfer roller 25, and is rotationally driven counterclockwise (R1) in the figure. Four-color toner images are multi-transferred onto the conveyed intermediate transfer belt 21 so as to overlap each other, thereby forming an image as a full-color toner image on the intermediate transfer belt 21. This image is carried on the intermediate transfer belt 21 and conveyed to a transfer portion (secondary transfer portion) configured as a nip portion between a secondary transfer roller 43 and the secondary transfer inner roller 22. By applying a bias voltage having a polarity opposite to the charging polarity of the toner to the secondary transfer roller 43 as transfer means, the image carried on the intermediate transfer belt 21 is secondarily transferred to the sheet P. Residual toner remaining on the intermediate transfer belt 21 after transfer is removed by a transfer cleaner 26.

[0016] The sheet P onto which the image has been transferred is delivered to a fixing device 50. The fixing device 50 has a fixing roller pair 51 that sandwiches and conveys the sheet P and a heat source such as a halogen lamp, and applies pressure and heat to the toner image carried on the sheet P. Thereby, the toner particles are melted and fixed, and a fixed image fixed on the sheet P is obtained.

[0017] Next, the conveyance operation of the sheet P by the image forming apparatus 1 will be described. The feed cassettes 31 and 32, which are examples of the sheet storage means, store the sheet P and are detachably attached to the apparatus main body 100. The sheet P stored in a stacked state in the feed cassettes 31 and 32 is fed one by one by the feed unit 40. The feed unit 40 includes a pickup roller 40a that feeds out the sheet P from the feed cassettes 31 and 32, and a feed roller 40b that receives and conveys the sheet P from the pickup roller 40a. The feed unit 40 also includes a separation roller 40c that separates the sheet P conveyed by the feed roller 40b from other sheets P. The separation roller 40c regulates the double feeding of sheets P other than the sheet P being conveyed (the uppermost sheet P) in contact with the feed roller 40b by applying a frictional force to the sheet P at the separation nip where the feed roller 40b and the separation roller 40c are in contact. Note that the feed unit 40 is an example of the feeding means for feeding the sheet P, and a belt method in which the sheet P is adsorbed to a belt member by a suction fan and conveyed, or a feeding means of a friction separation method using a pad may be used. Also, the user can directly set the sheet P on the manual feed tray 33 provided on the side of the apparatus main body 100, and the sheet P set on the manual feed tray 33 is fed by the feed unit.

[0018] The sheet P sent out from the feeding unit 40 is conveyed to the registration roller pair (hereinafter referred to as the registration roller pair) 42 via the pre-registration roller pair (hereinafter referred to as the pre-reg roller pair) 41. The leading end of the sheet P (that is, the downstream end in the sheet conveyance direction) abuts against the nip portion of the stopped registration roller pair 42, and the pre-reg roller pair 41 conveys the sheet P so that the sheet P bends (forms a loop), thereby correcting the skew of the sheet P. Thereafter, the registration roller pair 42 feeds the sheet P into the secondary transfer unit at a timing synchronized with the image forming operation by the image forming units PY to PK. In this way, the registration roller pair 42, which is an example of the registration means, aligns the positions of the sheet P and the image formed on the sheet P. The sheet P onto which the toner image has been transferred in the secondary transfer unit and on which the image has been fixed by the fixing device 50 is delivered to the sheet discharge unit 60 and is conveyed by the post-fixing roller pair 61 toward the switching member 64 capable of switching the conveyance path of the sheet P.

[0019] When the image formation on the sheet P is completed, the sheet P having the image formed on the first surface (front surface) is discharged to the discharge tray 80 by the discharge roller pair 62. When forming an image on the second surface (back surface) of the sheet P, the sheet P is delivered to the reverse conveyance unit 70 by the switching member 64 via the conveyance roller pair 63. The reverse conveyance unit 70 includes a reverse roller pair 71 that reversely conveys (switchbacks) the sheet P and a duplex path 79 that guides the sheet P switchbacked by the reverse roller pair 71 toward the registration roller pair 42. The reverse roller pair 71 conveys the sheet P a predetermined distance toward the discharge space above the discharge tray 80 and then conveys the sheet P in the reverse direction, thereby feeding the sheet P into the duplex path 79. A plurality of conveyance roller pairs (72, 73, 74) are arranged in the duplex path 79, as will be described in detail later, and convey the sheet P toward the registration roller pair 42 again. Then, the sheet P having the image formed on the second surface by passing through the secondary transfer unit and the fixing device 50 is discharged to the discharge tray 80 by the discharge roller pair 62.

[0020] Note that the above-described image forming engine 10 is an example of an image forming means, and for example, a direct transfer method in which a toner image formed on a photoreceptor is directly transferred to a sheet in a transfer unit may be employed. Further, the configuration of the image forming means may be an inkjet method or an offset printing method.

[0021] Hereinafter, a control configuration for controlling the operation of the image forming apparatus 1 will be described with reference to the block diagram of FIG. 2. The image forming apparatus 1 is equipped with a control unit 200 having functional units such as a CPU (Central Processing Unit) 201, a memory 202, an operation unit 203, an image forming control unit 205, and a sheet conveyance control unit 206. The CPU 201 controls the operations of each part of the image forming apparatus 1 by reading and executing a control program stored in the memory 202. The memory 202 includes, for example, a RAM (Random Access Memory) and a ROM (Read Only Memory), and stores various programs and various data in a predetermined storage area. Further, the memory 202 provides a work area when the CPU 201 executes the control program. The operation unit 203 has devices such as a liquid crystal panel and buttons, and accepts various operations performed by the user, such as input of various information (information such as size, basis weight, surface property, etc.) regarding the sheet used for image formation, and instructions for execution and interruption of image formation.

[0022] The image forming control unit 205 includes an exposure writing unit 13 that causes the exposure devices 13Y, 13M, 13C, and 13K to perform an image writing operation, and controls the image forming operation by issuing instructions to each part of the image forming engine 10. The sheet conveyance control unit 206 issues instructions to a feed motor 110, a discharge motor 160, etc. that drive various conveyance rollers, and controls the conveyance of the sheet P. The sensor control unit 207 controls the start and stop of detection by a registration sensor 44 and a duplex sensor 76, etc., which will be described later, and receives the detection results of these sensors. Further, the control unit 200 can receive various information regarding the sheet used for image formation from a computer 204 connected to the image forming apparatus 1 via a network.

[0023] (Sheet conveyance system) Next, the sheet conveyance system controlled by the sheet conveyance control unit 206 and its drive configuration will be described with reference to FIG. 3. The sheet conveyance system included in the image forming apparatus 1 includes a feed path 49, an image forming path 59, and a duplex path 79. These conveyance paths are conveyance spaces for passing the sheet P, which are formed by guide members supported by the apparatus main body 100 and guiding the sheet P. In the following description, the "sheet conveyance direction" shall represent the main conveyance direction of the sheet in the conveyance path where the target member is disposed.

[0024] The feed path 49 is a conveyance path for feeding the sheet P, and the feed unit 40 and the pre-registration roller pair 41 are disposed therein. The feed unit 40 is driven by the feed motor 110, and the pre-registration roller pair 41 is driven by the pre-registration motor 120. The image forming path 59 is a conveyance path for performing image formation while conveying the sheet P, and the registration roller pair 42, the secondary transfer roller 43 and the secondary transfer inner roller 22, and the fixing roller pair 51 are disposed therein. The registration roller pair 42 is driven by the registration motor 130, the secondary transfer inner roller 22 is driven by the ITB (Intermediate Transfer Belt) motor 140, and the fixing roller pair 51 is driven by the fixing motor 150.

[0025] The duplex path 79 is a conveyance path for conveying the sheet P sent out from the image forming path 59 again toward the image forming path 59 when performing duplex printing. In the duplex path 79, a conveyance roller pair 63, a reversing roller pair 71, a first duplex roller pair 72, a second duplex roller pair 73, and a third duplex roller pair 74 are disposed. The conveyance roller pair 63 conveys the sheet P guided from the image forming path 59 to the duplex path 79 by the switching member 64 toward the reversing roller pair 71. The reversing roller pair 71 receives the sheet P from the conveyance roller pair 63, reverses it, and feeds it into a portion extending downward substantially parallel to the image forming path 59 in the duplex path 79. The first to third duplex roller pairs 72 to 74 are arranged in this order along the direction from the reversing roller pair 71 toward the registration roller pair 42 in the duplex path 79.

[0026] The reversing roller pair 71 and the first duplex roller pair 72 are driven by a reversing motor 170, and the second duplex roller pair 73 and the third duplex roller pair 74 are driven by a duplex motor 180. The reversing motor 170 is a motor that can rotate in a first direction (forward rotation) and a second direction (reverse rotation) opposite thereto, and the first duplex roller pair 72 is connected to the reversing motor 170 via a one-way clutch 75. A duplex sensor 76 is disposed between the first duplex roller pair 72 and the second duplex roller pair 73 in the sheet conveyance direction as a detecting means capable of detecting a sheet. Further, a registration sensor 44 is disposed at a position near the upstream side of the registration roller pair 42 as another detecting means. These sensors can use, for example, a photoelectric sensor capable of detecting that light is blocked by a sheet.

[0027] The image forming path 59 corresponds to a first conveyance path where image forming means is disposed, and the duplex path 79 corresponds to a second conveyance path that guides a sheet reversed by the reversing roller pair 71 or the like toward the first conveyance path. The reversing roller pair 71 corresponds to a first conveyance means for reversely conveying a sheet from the first conveyance path. The first duplex roller pair 72, the second duplex roller pair 73, and the third duplex roller pair 74 correspond to a second conveyance means, a third conveyance means, and a fourth conveyance means, respectively, that are sequentially arranged along the sheet conveyance direction in the second conveyance path. Further, the reversing motor 170 corresponds to a first drive source that drives the first conveyance means and the second conveyance means, the duplex motor 180 corresponds to a second drive source that drives the third conveyance means and the fourth conveyance means, and the registration motor 130 corresponds to a third drive source that drives the registration means.

[0028] In addition, a discharge motor 160 for driving a conveyance roller pair (61 to 63) constituting the sheet discharge unit 60 is provided. Note that the sheet conveyance operation described below is also applicable to a configuration in which the reversing roller pair 71 also serves as a discharge means for discharging the sheet P (a configuration in which the sheet discharge unit is omitted).

[0029] (Duplex conveyance unit) A duplex transport unit 20 (FIG. 1), which is a transport unit arranged in a duplex path 79 of an image forming apparatus 1, will be described. As shown in FIGS. 4 and 5, the duplex transport unit 20 includes an inner duplex guide 81, a transport roller 63a supported by the inner duplex guide 81, an outer duplex guide 82, and a first duplex roller pair 72 supported by the outer duplex guide 82. The duplex transport unit 20 has a plurality of guide members for guiding a conveyed sheet and a plurality of transport rollers supported by the guide members for transporting the sheet, and is a transport unit that is detachable from the apparatus main body 100. In FIGS. 4 and 5, a drive cover 83, which will be described later, is not shown (in a transparent state).

[0030] The inner duplex guide 81 and the outer duplex guide 82 are arranged to face each other so as to guide a sheet P conveyed by the first duplex roller pair 72 from both the front and back sides, and are guide members that form a transport path between the inversion roller pair 71 and the second duplex roller pair 73 (FIG. 1). The inner duplex guide 81 and the outer duplex guide 82 have guide surfaces for guiding the sheet P, and openings for protruding each roller of the first duplex roller pair 72 into the transport path are provided in the guide surfaces.

[0031] The transport roller 63a is a roller member that constitutes a transport roller pair 63. In the present embodiment, the roller member that constitutes the transport roller pair 63 together with the transport roller 63a is attached to the apparatus main body 100 separately from the duplex transport unit 20. Further, the duplex transport unit 20 has a guide surface 85 (FIG. 4) for guiding the sheet P conveyed by the transport roller pair 63. An opening through which the transport roller 63a is exposed is provided in the guide surface 85. The guide surface 85 may be a part of the inner duplex guide 81 or may be constituted by a separate member fixed to the inner duplex guide 81.

[0032] The inner duplex guide 81 is the first guide member of the present embodiment. The transport roller 63a is the first transport roller of the present embodiment that is supported by the first guide member and transports the sheet. The outer duplex guide 82 is the second guide member of the present embodiment. The first duplex roller pair 72 is the second transport roller of the present embodiment that is supported by the second guide member and transports the sheet.

[0033] The above-described duplex conveyance unit 20 is an example of a conveyance unit having a plurality of guide members and a plurality of conveyance rollers, and the number and arrangement of the guide members and conveyance rollers can be changed according to the specific configuration of the sheet conveyance device. For example, instead of the inner duplex guide 81, or in addition to the inner duplex guide 81, a guide member for guiding the sheet P conveyed by the conveyance roller pair 63 may be provided, and the conveyance roller 63a may be supported by the guide member. Further, both of the two roller members constituting the conveyance roller pair 63 may be arranged in the duplex conveyance unit 20.

[0034] (Drive configuration of duplex conveyance unit) Next, the drive configuration of the duplex conveyance unit 20 will be described. As shown in FIGS. 4 and 5, the inner duplex guide 81 and the outer duplex guide 82 have side plates 81a and 82a as side portions that extend substantially perpendicular to the Y direction at the ends of the guide surfaces that extend in the Y direction.

[0035] As shown in FIG. 4, on the side plate 81a of the inner duplex guide 81, a first drive gear 93 attached to the roller shaft of the conveyance roller 63a and First a first input gear 91 for inputting a driving force to the drive gear 93 are rotatably arranged. The first drive gear 93 and the first input gear 91 are rotating members that rotate about axes extending in the Y direction, respectively.

[0036] In a state where the duplex conveyance unit 20 is mounted on the apparatus main body 100, the first input gear 91 meshes with a first output gear on the apparatus main body 100 side that is connected to the discharge motor 160 (FIG. 3). Thereby, the driving force of the discharge motor 160 is transmitted to the conveyance roller 63a via the first input gear 91 and the 1 drive gear 93, and the conveyance roller pair 63 is rotationally driven. That is, the gear train 9A including the first drive gear 93 and the first input gear 91 is provided on one side portion in the sheet width direction (Y direction) of the first guide member, and functions as a first drive transmission unit that transmits the driving force input from the apparatus main body 100 to the first conveyance roller.

[0037] On the other hand, as shown in FIG. 5, on the side plate 82a of the double-sided outer guide 82, a second drive gear 94 for driving the first double-sided roller pair 72, idler gears 95, 96, 97, a planetary gear 98, and a second input gear 92 are rotatably arranged respectively. The second drive gear 94, the planetary gear 9 8 , the idler gears 95 to 97 and the second input gear 92 are rotating members that rotate about axes extending in the Y direction respectively.

[0038] The second drive gear 94 is connected to the second input gear 92 via a gear train composed of the idler gears 95 to 97 and the planetary gear 98 that mesh with each other. In a state where the double-sided conveyance unit 20 is attached to the apparatus main body 100, the second input gear 92 meshes with the second output gear on the apparatus main body 100 side that is connected to the reverse motor 170 (FIG. 3). Thereby, the driving force of the reverse motor 170 is transmitted to the first double-sided roller pair 72 via the second input gear 92, the idler gears 95 to 97, the planetary gear 98, and the second drive gear 94, and the first double-sided roller pair 72 is rotationally driven. That is, the gear train 9B composed of the second drive gear 94, the idler gears 95 to 97, the planetary gear 98, and the second input gear 92 is provided on one side portion in the sheet width direction (Y direction) of the second guide member, and functions as a second drive transmission unit that transmits the driving force input from the apparatus main body 100 to the second conveyance roller.

[0039] In this embodiment, the first drive transmission unit and the second drive transmission unit composed of gear trains are exemplified, but other transmission mechanisms may be used. For example, a belt transmission mechanism may be used instead of the gear train. Also, in this embodiment, the gear trains 9A and 9B are described as being input with driving forces from separate motors respectively, but the first drive transmission unit and the second drive transmission unit may be configured to receive the supply of driving force from a common drive source.

[0040] (Drive cover of the double-sided conveyance unit) Next, a drive cover 83 as a cover member that covers the drive transmission unit provided in the double-sided conveyance unit 20 will be described. FIG. 6 is a perspective view showing a state before the drive cover 83 is attached to the double-sided conveyance unit 20, and FIG. 7(a) is a perspective view showing the double-sided conveyance unit 20 with the drive cover 83 attached. FIG. 7(b) is an enlarged view showing a part of the double-sided conveyance unit 20 viewed in the direction indicated by the arrow 7B in FIG. 7(a).

[0041] As shown in FIGS. 6 and 7(a), the drive cover 83 is detachably attached to the side plates 81a and 82a of the double-sided inner guide 81 and the double-sided outer guide 82 from one side in the Y direction (Y direction plus side). When the double-sided conveyance unit 20 is viewed from the Y direction in the attached state, at least a part of the gears in the gear trains 9A and 9B are covered by the drive cover 83, and each gear is held between the side plates 81a and 82 a and the drive cover 83. That is, the drive cover 83 functions as a cover member that covers at least a part of the first drive transmission unit and at least a part of the second drive transmission unit when viewed from one side in the sheet width direction (Y direction plus side).

[0042] The drive cover 83 has positioning holes 310 and long holes 311, which are engagement portions that open to the guide side in the Y direction (Y direction minus side), as positioning shapes with respect to the double-sided inner guide 81 and the double-sided outer guide 82. The double-sided inner guide 81 is provided with a first positioning shaft 300 that protrudes from the side plate 81a toward the drive cover side in the Y direction (Y direction plus side) as a first positioning shape for positioning the drive cover 83. Further, the double-sided outer guide 82 is provided with a second positioning shaft 301 that protrudes from the side plate 82a toward the drive cover side in the Y direction (Y direction plus side) as a second positioning shape for positioning the drive cover 83. Note that the positioning shape is not limited to a case where the guide member side is a protrusion (convex shape) and the drive cover side is an opening (concave shape), and the guide member side may be an opening (concave shape) and the drive cover side may be a protrusion (convex shape).

[0043] A mounting hole 314 penetrating in the Y direction is provided at approximately the center of the drive cover 83. The double-sided outer guide 82 is provided with a cylindrical portion 304 having a female thread formed therein for engaging with the screw 320 inserted into the mounting hole 314. Note that, although the present embodiment will be described assuming that the drive cover 83 is fixed to the double-sided outer guide 82 with screws, the drive cover 83 may be configured to be fixed to the double-sided inner guide 81 with screws, or may be fixed to both guides with two or more screws.

[0044] Furthermore, the drive cover 83 has a positioning member 315 in which positioning grooves 312, 313, which are openings for positioning, are formed (see FIG. 6). The positioning member 315 is a plate-like member that is bent relative to a main body portion 83a of the drive cover 83 that extends approximately perpendicular to the Y direction so as to cover the gear trains 9A, 9B, and extends from an end of the main body portion 83a in the X direction toward the guide side in the Y direction (the negative side in the Y direction). The two positioning grooves 312, 313 preferably extend parallel to each other in the Y direction, and are arranged side by side in a direction perpendicular to the Y direction (approximately the Z direction) within the positioning member 315.

[0045] The double-sided inner guide 81 has a positioning protrusion 303 which is a protrusion that fits into one of the positioning grooves 313 of the drive cover 83. The double-sided outer guide 82 has a positioning protrusion 302 which is a protrusion that fits into the other positioning groove 312 of the drive cover 83. The positioning protrusions 302, 303 are provided on the side plates 81a, 81b. 2a The positioning protrusions 302, 303 protrude from the ends of the positioning members 315 in a direction (the negative X-direction in this embodiment) that enters the openings of the positioning grooves 312, 313 and have a long and thin projection shape that extends in the Y-direction. The positioning protrusions 302, 303 preferably extend parallel to each other in the Y-direction and are arranged side by side in a direction perpendicular to the Y-direction (approximately the Z-direction) within the positioning member 315 when the double-sided inner guide 81 and the double-sided outer guide 82 are temporarily assembled.

[0046] The positioning projection 303 of the double-sided inner guide 81 is the first fitting portion of the present embodiment, and the positioning groove 313 of the drive cover 83 corresponding to the positioning projection 303 is the third fitting portion of the present embodiment. The positioning projection 302 of the double-sided outer guide 82 is the second fitting portion of the present embodiment, and the positioning groove 312 of the drive cover 83 corresponding to the positioning projection 302 is the fourth fitting portion of the present embodiment.

[0047] When attaching the drive cover 83, as shown in FIG. 6, position the drive cover 83 such that the first positioning shaft 300 of the double-sided outer guide 82 is inserted into the positioning hole 310 and the second positioning shaft 301 of the double-sided outer guide 82 is inserted into the long hole 311. Then, as shown in FIG. 7(b), fit one positioning groove 313 of the positioning member 315 to the positioning projection 303 of the double-sided inner guide 81 and the other positioning groove 312 to the positioning projection 302 of the double-sided outer guide 82. That is, fit the first fitting portion of the first guide member and the third fitting portion of the cover member, and fit the second fitting portion of the second guide member and the fourth fitting portion of the cover member. Thereafter, as shown in FIG. 6, fasten the mounting hole 314 of the drive cover 83 and the cylindrical portion 304 of the double-sided outer guide 82 with a screw 320 to fix the drive cover 83 to the double-sided inner guide 81 and the double-sided outer guide 82.

[0048] (Attachment of the double-sided conveyance unit to the apparatus main body) Next, a method for attaching the double-sided conveyance unit 20 to the apparatus main body 100 will be described. FIG. 8(a) is a perspective view showing a state before attaching the double-sided conveyance unit 20 to the apparatus main body 100, and FIG. 8(b) is a perspective view showing a state before attaching the double-sided conveyance unit 20 to the apparatus main body 100. FIGS. 8(a) and 8(b) both show the drive side (the +Y direction side where the gear trains 9A and 9B are provided) of the double-sided conveyance unit 20.

[0049] As shown in FIG. 8(a), the duplex conveyance unit 20 is provided with a positioning hole 305 and a long hole 306 as a shape (a portion to be positioned) for positioning to the apparatus main body 100. In the present embodiment, both the positioning hole 305 and the long hole 306 are formed in a mounting plate 82b which is a part of the double-sided outer guide 82 (see also FIGS. 6 and 7(a)). The mounting plate 82b is a member serving as a mounting seat surface for attaching the duplex conveyance unit 20 to the apparatus main body 100. The mounting plate 82b is formed by bending substantially perpendicular to the side plate 82a of the double-sided outer guide 82, and is a plate-like member extending so as to protrude to the plus side in the Y direction from the drive cover 83. On the other hand, on the conveyance base 84 of the apparatus main body 100, a positioning rib 331 which is a protrusion corresponding to the positioning hole 305 of the mounting plate 82b and a positioning boss 330 which is a protrusion corresponding to the long hole 306 of the mounting plate 82b are provided (FIG. 8(a)). Both the positioning rib 331 and the positioning boss 330 are examples of positioning shapes for positioning the conveyance unit with respect to the apparatus main body. Note that the positioning shape is not limited to a case where the apparatus main body is a protrusion (convex shape) and the conveyance unit side is an opening (concave shape), and the apparatus main body side may be an opening (concave shape) and the conveyance unit side may be a protrusion (convex shape).

[0050] Further, mounting holes 308 and 309 are provided in the mounting plate 82b. On the conveyance base 84 of the apparatus main body 100, cylindrical portions 333 and 334 are provided in which female threads are formed for screwing screws 321 and 322 through the mounting holes 308 and 309.

[0051] When attaching the duplex conveyance unit 20 to the apparatus main body 100, the duplex conveyance unit 20 is positioned such that the positioning rib 331 on the apparatus main body side is inserted into the positioning hole 305 of the mounting plate 82b and the positioning boss 330 on the apparatus main body side is inserted into the long hole 306 of the mounting plate 82b. Thereafter, the mounting plate 82b is fastened to the conveyance base 84 by screwing the screws 321 and 322 passed through the mounting holes 308 and 309 into the cylindrical portions 333 and 334 of the conveyance base 84.

[0052] Next, with reference to FIGS. 9(a) and 9(b), the mounting method of the non-driving side (the minus Y direction side, which is the side opposite to the gear trains 9A and 9B) of the duplex conveyance unit 20 will be described. FIG. 9(a) is a perspective view showing the state before the duplex conveyance unit 20 is mounted on the apparatus main body 100, and FIG. 9(b) is a perspective view showing the state after the duplex conveyance unit 20 is mounted on the apparatus main body 100.

[0053] As shown in FIG. 9(a), on the non-driving side of the duplex conveyance unit 20 as well, a mounting plate 82c is provided as a part of the duplex outer guide 82. The mounting plate 82c is provided with positioning holes 307 as a shape for positioning to the apparatus main body 100. On the other hand, on the conveyance base 84 of the apparatus main body 100, a positioning boss 332, which is a protrusion corresponding to the positioning holes 307 of the mounting plate 82c, is provided. Further, the mounting plate 82c is provided with mounting holes 318 and 319. On the conveyance base 84 of the apparatus main body 100, cylindrical portions 335 and 336 having female threads formed therein for screwing screws 323 and 324 through the mounting holes 318 and 319 are provided.

[0054] When mounting the duplex conveyance unit 20 on the apparatus main body 100, the duplex conveyance unit 20 is positioned such that the positioning boss 332 on the apparatus main body side is inserted into the positioning holes 307 of the mounting plate 82c. Then, by screwing the screws 323 and 324 that pass through the mounting holes 318 and 319 into the cylindrical portions 335 and 336 of the conveyance base 84, the mounting plate 82c is fastened to the conveyance base 84. As described above, by fastening the driving side and the non-driving side of the duplex conveyance unit 20 to the conveyance base 84 respectively, the mounting of the duplex conveyance unit 20 to the apparatus main body 100 is completed.

[0055] Here, the apparatus main body 100 includes a door member (the right side surface portion of the apparatus main body 100 in FIG. 1) that is provided so as to be openable and closable with respect to the frame that houses the image forming engine 10 in order to open at least a part of the conveyance path provided in the image forming apparatus 1. That is, the conveyance base 84 to which the duplex conveyance unit 20 is attached can be configured as a part of the door member that is provided so as to be openable and closable within the apparatus main body 100. Alternatively, the duplex conveyance unit 20 may be configured to be attached to a part of the frame that houses the image forming engine 10 or to the conveyance base 84 as a member fixed to this frame.

[0056] (Advantages of the present embodiment) In the process of attaching the drive cover 83 described above, the positioning protrusions 302 and 303 are fitted and held inside the positioning grooves 312 and 313, thereby restricting the relative movement between the drive cover 83 and the duplex inner guide 81 and the relative movement between the drive cover 83 and the duplex outer guide 82. That is, by the fitting of the positioning protrusions 302 and 303 and the positioning grooves 312 and 313, the three members, i.e., the side plate 81a of the duplex inner guide 81 that holds the gear trains 9A and 9B, the side plate 82a of the duplex outer guide 82, and the drive cover 83, are positioned relative to each other. In a state where the drive cover 83 is attached, each gear of the gear trains 9A and 9B is held between the side plates 81a and 82a of the duplex inner guide 81 and the duplex outer guide 82 and the contact surfaces (bearing portions) provided on the drive cover 83, and the movement in the axial direction (Y direction) is restricted.

[0057] In this way, by enabling a plurality of guide members to be positioned relative to each other with a single cover member, it is possible to ensure the positioning accuracy of the gear trains 9A and 9B, which are members involved in drive transmission provided on each guide member, with a simple configuration. The "positioning accuracy" referred to here means, for example, when a driving force from the drive source of the apparatus main body 100 is input to the gear trains 9A and 9B after the duplex conveyance unit 20 is attached to the apparatus main body 100, the side plates 81a and 82 a receive a force and bend, causing the axial distance between the gears constituting the gear trains 9A and 9B and the parallelism of the axes to be disturbed.

[0058] In this embodiment, the side plates 81a of the double-sided inner guide 81, the side plates 82a of the double-sided outer guide 82, and the drive cover 83 that hold the gear trains 9A and 9B are positioned relative to each other by fitting the positioning protrusions 302 and 303 and the positioning grooves 312 and 313, thereby enhancing rigidity. As a result, even when a driving force is input to the gear trains 9A and 9B, the axial distance and the parallelism of the axes between the gears constituting the gear trains 9A and 9B are less likely to be disrupted. If the positioning accuracy of the gear trains 9A and 9B is improved, effects such as an improvement in the transmission efficiency of the gear trains 9A and 9B, suppression of noise, and improvement in durability by suppressing stress can be expected.

[0059] Further, in this embodiment, as the shape of the fitting portion for positioning, a groove shape and a protrusion shape extending along the Y direction (sheet width direction), which is the mounting direction of the drive cover 83, are adopted. Therefore, the groove shape and the protrusion shape are fitted as the drive cover 83 is mounted. Thereby, the drive cover 83 can be positioned with respect to the side plates 81a and 82a of the double-sided inner guide 81 and the double-sided outer guide 82 without performing a special operation of fitting the fitting portions to each other for positioning.

[0060] Further, in this embodiment, the positioning protrusions 302 and 303 of the double-sided inner guide 81 and the double-sided outer guide 82 are arranged in the vicinity of the first input gear 91 and the second input gear 92 of the gear trains 9A and 9B. That is, the positioning protrusions 302 and 302 are provided at the ends of the side plates 81a and 82a of the double-sided inner guide 81 and the double-sided outer guide 82 on the side (the negative X direction side) where the first input gear 91 and the second input gear 92 are provided in the X direction orthogonal to the sheet width direction (Y direction) (FIG. 6). And the positioning protrusions 302 and 302 are arranged side by side in the Z direction orthogonal to the X direction and the Y direction when viewed in the X direction (FIGS. 7(a, b)). In other words, the first fitting portion and the second fitting portion are provided at the ends of the side portion of the first guide member and the side portion of the second guide member on the side where the first input gear and the second input gear are arranged in the first direction orthogonal to the sheet width direction. Further, the first fitting portion and the second fitting portion are arranged side by side in the sheet width direction and the second direction orthogonal to the first direction when viewed in the first direction. With such a configuration, the positioning accuracy around the input gear can be ensured with higher accuracy.

[0061] <Second Embodiment> Next, the second embodiment will be described. In the first embodiment described above, protrusion shapes were provided on each of the two guide members of the duplex conveyance unit 20, and two groove shapes that fit into the two protrusion shapes were provided on the drive cover 83. In this embodiment, two protrusion shapes are provided on the drive cover 83, and groove shapes that fit into any of the protrusion shapes are provided on each of the two guide members of the duplex conveyance unit 20. Hereinafter, elements denoted by the same reference numerals as those in the first embodiment shall have substantially the same configurations and operations as those described in the first embodiment.

[0062] FIG. 10(a) is a perspective view showing the duplex conveyance unit 20 according to this embodiment with the drive cover 83 attached. FIG. 10(b) is a partial cross-sectional enlarged view of the duplex conveyance unit 20 at the cutting position indicated by the line XB-XB in FIG. 10(a). FIG. 11(a) is a perspective view showing the state before the drive cover 83 according to this embodiment is attached to the duplex conveyance unit 20. FIG. 11(b) is an enlarged view showing a part of the duplex conveyance unit 20 as viewed in the direction indicated by the arrow 11B in FIG. 11(a). FIG. 12(a) is a perspective view of the duplex conveyance unit 20 shown in FIG. 11(a) viewed from a different direction. FIG. 12(b) is an enlarged view showing a part of the duplex conveyance unit 20 as viewed in the direction indicated by the arrow 12B in FIG. 12(a).

[0063] As shown in FIG. 11(a), gear trains 9A and 9B similar to those in the first embodiment are supported by the side plates 81a and 82a of the inner duplex guide 81 and the outer duplex guide 82. The drive cover 83 is detachably attached to the side plates 81a and 82a of the inner duplex guide 81 and the outer duplex guide 82 from one side in the Y direction (the Y-direction positive side). When the duplex conveyance unit 20 is viewed from the Y direction in the attached state of FIG. 10(a), at least a part of the gears of the gear trains 9A and 9B are covered by the drive cover 83, and each gear is held between the side plates 81a and 82 a and the drive cover 83.

[0064] As shown in FIGS. 10(b) and 12(a, b), the drive cover 83 has a positioning member 315 provided with positioning protrusions 402 and 403 which are convex portions for positioning. The positioning protrusions 402 and 403 are in a protrusion shape that protrudes in the X direction from the positioning member 315 and extends slenderly in the Y direction, preferably extending parallel to each other in the Y direction and arranged so as to be aligned in a direction (substantially the Z direction) orthogonal to the Y direction within the positioning member 315.

[0065] As shown in FIGS. 11(a, b), the double-sided inner guide 81 has a positioning groove 413 which is an opening for positioning corresponding to one of the positioning protrusions 403. Further, the double-sided outer guide 82 has a positioning groove 412 which is an opening for positioning corresponding to the other positioning protrusion 402. The positioning grooves 412 and 413 are preferably arranged to extend parallel to each other in the Y direction and to be aligned in a direction (substantially the Z direction) orthogonal to the Y direction in a state where the double-sided inner guide 81 and the double-sided outer guide 82 are temporarily assembled.

[0066] The positioning groove 413 of the double-sided inner guide 81 is the first fitting portion of the present embodiment, and the positioning protrusion 403 of the drive cover 83 corresponding to the positioning groove 413 is the third fitting portion of the present embodiment. The positioning groove 412 of the double-sided outer guide 82 is the second fitting portion of the present embodiment, and the positioning protrusion 402 of the drive cover 83 corresponding to the positioning groove 412 is the fourth fitting portion of the present embodiment.

[0067] When attaching the drive cover 83, as shown in FIGS. 11(a) and 12(a), insert the first positioning shaft 300 of the double-sided outer guide 82 into the positioning hole 310, and insert the second positioning shaft 301 of the double-sided outer guide 82 into the long hole 311 to position the drive cover 83. Then, as shown in FIG. 10(b), fit one positioning protrusion 403 of the positioning member 315 into the positioning groove 413 of the double-sided inner guide 81, and fit the other positioning protrusion 402 into the positioning groove 412 of the double-sided outer guide 82. That is, fit the first fitting portion of the first guide member and the third fitting portion of the cover member, and fit the second fitting portion of the second guide member and the fourth fitting portion of the cover member. Thereafter, as shown in FIG. 10(a), fasten the mounting hole 314 of the drive cover 83 and the cylindrical portion 304 (FIG. 11(a)) of the double-sided outer guide 82 with screws 320 to fix the drive cover 83 to the double-sided inner guide 81 and the double-sided outer guide 82.

[0068] Thus, also according to this embodiment, by enabling a single cover member to position a plurality of guide members relative to each other, it is possible to ensure the positioning accuracy of the gear trains 9A, 9B, which are members involved in drive transmission provided on each guide member, with a simple configuration.

[0069] (Other Embodiments) In the above-described embodiment, the sheet conveyance device incorporated in the image forming apparatus 1 has been described. However, this technology can also be applied to other sheet conveyance devices that handle sheet materials. For example, a sheet feeding device that is connected to an image forming apparatus having image forming means and feeds sheets one by one to the image forming apparatus, and a sheet processing device that receives sheets from the image forming apparatus and performs processes such as binding processing can be mentioned.

Description of Reference Numerals

[0070] 20…Conveying unit (duplex conveying unit) / 81…First guide member (inner guide for duplex) / 82…Second guide member (outer guide for duplex) / 83…Cover member (drive cover) / 9A…First drive transmission part (gear train) / 9B…Second drive transmission part (gear train) / 100…Apparatus main body / 303, 413…First fitting part (positioning projection, positioning groove) / 302, 412…Second fitting part (positioning projection, positioning groove) / 313, 403…Third fitting part (positioning groove, positioning projection) / 312, 402…Fourth 4 Fitting part (positioning groove, positioning projection)

Claims

1. A sheet conveying device having a device main body and a conveying unit detachably attached to the device main body for conveying a sheet, The conveying unit includes a first guide member for guiding the conveyed sheet, a first conveying roller supported by the first guide member for conveying the sheet, a second guide member for guiding the conveyed sheet, a second conveying roller supported by the second guide member for conveying the sheet, a first drive transmission unit disposed on one side in the sheet width direction of the first guide member for transmitting a driving force input from a drive source provided in the device main body to the first conveying roller, a second drive transmission unit disposed on the one side in the sheet width direction of the second guide member for transmitting a driving force input from a drive source provided in the device main body to the second conveying roller, a cover member covering at least a part of the first drive transmission unit and at least a part of the second drive transmission unit when viewed from the one side in the sheet width direction, and the first guide member includes a first fitting portion, the second guide member includes a second fitting portion, the cover member includes a third fitting portion that fits with the first fitting portion and a fourth fitting portion that fits with the second fitting portion, The sheet conveying device is characterized in that the first guide member, the second guide member, and the cover member are positioned relative to each other by fitting of the first fitting portion and the third fitting portion and fitting of the second fitting portion and the fourth fitting portion.

2. In the sheet conveying device according to claim 1, the cover member has a plate-shaped positioning member, both the third fitting portion and the fourth fitting portion are openings formed in the positioning member, The sheet conveying device is characterized in that the first fitting portion and the second fitting portion are convex portions that respectively fit into the opening portion.

3. In the sheet conveying device according to claim 1, The cover member has a plate-shaped positioning member, Both the third fitting portion and the fourth fitting portion are convex portions formed on the positioning member, The sheet conveying device is characterized in that the first fitting portion and the second fitting portion are opening portions that respectively fit into the convex portions.

4. In the sheet conveying device according to claim 2 or 3, Each of the opening portions has a groove shape extending in the sheet width direction, Each of the convex portions has a protrusion shape extending in the sheet width direction, and the cover member fits into the groove shape as it is mounted on the first guide member and the second guide member from one side in the sheet width direction. The sheet conveying device is characterized by this.

5. In the sheet conveying device according to any one of claims 2 to 4, The sheet conveying device is characterized in that each of the convex portions protrudes in a direction orthogonal to the mounting direction in which the cover member is mounted on the first guide member and the second guide member.

6. In the sheet conveying device according to any one of claims 1 to 5, The first drive transmission portion has a first input gear that receives a driving force from a drive source provided in the device main body, The second drive transmission portion has a second input gear that receives a driving force from a drive source provided in the device main body, The first fitting portion and the second fitting portion are provided at ends on the side where the first input gear and the second input gear are arranged with respect to a first direction orthogonal to the sheet width direction, among the side portions of the first guide member and the side portions of the second guide member, and are arranged side by side in the sheet width direction and a second direction orthogonal to the first direction when viewed in the first direction. A sheet conveying device characterized by this.

7. In the sheet conveying device according to any one of claims 1 to 6, At least one of the side portions of the first guide member and the side portions of the second guide member is provided with a mounting seat surface for mounting the conveying unit to the device main body. A sheet conveying device characterized by this.

8. In the sheet conveying device according to claim 7, The mounting seat surface is provided with a to-be-positioned portion for positioning the conveying unit with respect to the device main body by engaging with a positioning shape provided on the device main body. A sheet conveying device characterized by this.

9. In the sheet conveying device according to any one of claims 1 to 8, The cover member has mounting holes fixed to the first guide member or the second guide member by screws, The first guide member has a first positioning shape that engages with the cover member at a position different from the first fitting portion and the screw to position the cover member, The second guide member has a second positioning shape that engages with the cover member at a position different from the second fitting portion and the screw to position the cover member. A sheet conveying device characterized by this.

10. In the sheet conveying device according to any one of claims 1 to 9, The first guide member and the second guide member are arranged to face each other so as to form a conveyance path for the sheet. A sheet conveying device characterized by this.

11. In the sheet conveying apparatus according to any one of claims 1 to 10, further comprising reversing means for reversing a sheet on which an image has been formed on the first side when forming images on both sides of the sheet, the first conveying roller conveys the sheet toward the reversing means, the second conveying roller conveys the sheet reversed by the reversing means for forming an image on a second side opposite to the first side, and a sheet conveying apparatus characterized by this.

12. In the sheet conveying apparatus according to any one of claims 1 to 11, the apparatus main body includes a door member provided to be openable and closable, the conveying unit is attached to the door member, and a sheet conveying apparatus characterized by this.

13. a sheet conveying apparatus according to any one of claims 1 to 12, image forming means for forming an image on a sheet conveyed by the sheet conveying apparatus, and an image forming apparatus characterized by including this.

Images