Patent Application
20170036873
Field of the Invention
The present invention relates to a sheet conveyance apparatus conveying sheets, and an image forming apparatus equipped with the same.
Description of the Related Art
In the case in which sheet jam or other abnormalities occur within an image forming apparatus, it is desirable that an operator such as a user or a service engineer has a prompt solution to access internal components of the apparatus so that restoring operations are enabled. Japanese Patent Publication No. 2770321 discloses an image forming apparatus having a first chute member that moves in swinging motion corresponding to opening and closing of a cover member, and a second chute member forming a sheet conveyance path between the first chute member and capable of moving in swinging motion with respect to a body frame. According to the image forming apparatus, when the operator opens the cover member, the second chute member positioned on an inner side of the first chute member is pivoted toward an outer side of the apparatus body by its own weight. Thereby, the member positioned on an inner side of the second chute member is exposed, and a state is realized where the operator can perform restoring operations.
When a guide member pivoting to the outer side of the apparatus body, such as the second chute member according to the above patent document, is provided, the guide member may interfere with other members in pivoting to a large pivot angle. In order to cope with the problem, a regulation member may be provided to regulate a pivoting range of the guide member by abutting against a guide surface, i.e., outer side surface with respect to the apparatus body, of the guide member. However, if such regulation member is provided, scratch marks and other damages formed on the guide surface by the regulation member may cause such a conveyance abnormality that the sheet is caught by the damaged portion, and the conveyance performance of the sheet may be deteriorated.
According to one aspect of the present invention, a sheet conveyance apparatus includes an apparatus body, a cover member including a first guide surface configured to guide a sheet, the cover member being configured to switch between a close state and an open state with respect to the apparatus body, a guide member supported on the apparatus body pivotally to an outer side of the apparatus body, the guide member including a second guide surface opposing to the first guide surface and an abutment portion configured to be depressed from the second guide surface, a conveyance unit configured to convey a sheet through a path between the first guide surface and the second guide surface, and a regulation portion supported on the apparatus body. The regulation portion is formed to abut against the abutment portion in a state where the cover member is switched from the close state to the open state so that a pivot angle of the guide member is regulated not to exceed a predetermined angle.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention.
Now, preferred embodiments of the present disclosure will be described with reference to the drawings. In the following description, a state in which an image forming apparatus is seen from a front side, i.e., viewpoint of
An image forming apparatus 201 according to the present embodiment is a full-color laser beam printer, a general arrangement of which is illustrated in
The image forming unit 201B is a so-called four-drum full-color image forming unit having a laser scanner 210, four process cartridges 211, and an intermediate transfer unit 201C. The process cartridges form toner images of respective colors, which are yellow (Y), magenta (M), cyan (C) and black (K). Each process cartridge 211 include a photosensitive drum 212 composed of photoconductor, i.e., image bearing member, a charger 213, i.e., charging unit, a developer 214, i.e., image developing unit, and a cleaner, i.e., cleaning unit, not shown. A toner cartridge 215 storing toners of respective colors is detachably attached to the apparatus body 201A at an upper portion of the image forming unit 201B.
The intermediate transfer unit 201C includes an intermediate transfer belt 216, i.e., intermediate transfer body, wound around a drive roller 216a and a tension roller 216b, and the unit is arranged above the four process cartridges 211. The intermediate transfer belt 216 is arranged to contact the photosensitive drums 212 of the respective process cartridges 211, and driven to rotate in a counterclockwise direction, i.e., direction of arrow Q, by the drive roller 216a driven by a drive unit not shown. The intermediate transfer unit 201C has primary transfer rollers 219 that contact an inner circumferential surface of the intermediate transfer belt 216 at positions opposing to the respective photosensitive drums 212, and primary transfer portion T1 are formed as nip portions of the intermediate transfer belt 216 and the photosensitive drums 212. Further, the image forming unit 201B includes a secondary transfer roller 217 that contacts an outer circumferential surface of the intermediate transfer belt 216 at a position opposing to the drive roller 216a. A secondary transfer portion T2 where a toner image borne on the intermediate transfer belt 216 is transferred to the sheet P is formed as a nip portion of the secondary transfer roller 217 and the intermediate transfer belt 216.
In the respective process cartridges 211 arranged as described, an electrostatic latent image is drawn on the surface of the photosensitive drum 212 by the laser scanner 210, and toner is supplied from the developers 214 to form toner images of respective colors charged with negative polarity. The toner images are sequentially transferred in multi layers, i.e., primarily transferred, to the intermediate transfer belt 216 at the respective primary transfer portion T1 by applying a transfer bias voltage of positive polarity to the primary transfer rollers 219, and a full-color toner image is formed on the intermediate transfer belt 216.
Simultaneously as the above-described toner image forming process, the sheet P fed from the sheet feeding unit 201E is conveyed toward a registration roller pair 240, where skewing of the sheet P is corrected by the registration roller pair 240. The registration roller pair 240 conveys the sheet P to the secondary transfer portion T2 at a timing matching the transfer timing of the full-color toner image formed on the intermediate transfer belt 216. The toner image borne on the intermediate transfer belt 216 is secondarily transferred to the sheet P at the secondary transfer portion T2 by applying a transfer bias voltage of positive polarity to the secondary transfer roller 217.
The sheet P to which the toner image has been transferred is heated and pressed by the fixing unit 220, and a color image is fixed onto the sheet P. The sheet P with the image fixed thereto is discharged by a discharge roller pair 225 to the sheet discharge tray 230 and supported on the tray. When images are to be formed on both sides of the sheet P, the sheet P having passed the fixing unit 220 is moved in switch-back motion by a reverse conveyance roller pair 222 capable of forward/reverse rotation provided in a reverse conveyance unit 201D. Thereafter, the sheet P is conveyed again to the image forming unit 201B via a re-conveyance path R, so that an image is formed on the rear side of the sheet P.
Next, a configuration of the sheet feeding apparatus will be described with reference to the sheet feeding apparatus 100C, the third one from the top. The first, second and fourth sheet feeding apparatuses 100A, 100B and 100D from the top include similar components as the sheet feeding apparatus 100C, so that components having a similar configuration and operation are denoted with the same reference numbers, and detailed descriptions thereof will be omitted. It is noted that while the image forming apparatus 201 according to the present embodiment includes four sheet feeding apparatuses 100A, 100B, 100C and 100D, a similarly configured sheet feeding apparatus can additionally be provided below the sheet feeding apparatus 100D, for example.
As illustrated in
The tray 105 has a lower portion supported by the tray lifting plate 109, and disposed pivotally in a vertical direction around a pivot shaft 105a provided at an upstream side, i.e., left side in
The feeding unit 101 separating and feeding the sheets P supported on the cassette 103 one by one includes a pickup roller 102, a feed roller 107, a separation roller 108, and so on. These rollers (102, 107 and 108) are arranged so that axial directions thereof are arranged in a direction orthogonal to a sheet feeding direction, that is, in a perpendicular direction to the page of
An elevating plate 111 extending upstream in the sheet feeding direction is supported on the sheet feed drive shaft 107A and pivotable in a vertical direction. The pickup roller 102 is attached to a pickup roller shaft 102A pivotally supported on a leading end portion of the elevating plate 111, and connected to the sheet feed drive shaft 107A via an idler gear 114 supported by the elevating plate 111. A transmission-type (thrubeam-type) height detection sensor 110 capable of detecting a height position of the elevating plate 111 is arranged near the elevating plate 111. The height detection sensor 110 generates an ON signal by detecting a detection flag not shown provided on the elevating plate 111 when the feed roller 107 is at a predetermined height position that is set such that the feed roller 107 contacts a sheet supported on the tray 105 (hereinafter referred to as a sheet feeding position).
The sheet conveyance unit 104 includes a conveyance roller pair (vertical-path roller) 121, i.e., conveyance unit, a duplex guide 122, i.e., guide member, an openable cover 124, i.e., cover member, and a stopper 123, i.e., regulation portion. The sheet conveyance unit 104 is a sheet conveyance apparatus conveying the sheet P via the vertical path 126 formed between the openable cover 124 and the duplex guide 122.
The conveyance roller pair 121 is composed of a first conveyance roller 121a rotatably supported by the apparatus body via the sheet feed frame 125 and a second conveyance roller 121b rotatably supported by the openable cover 124. The conveyance roller pair 121 is arranged downstream, in a sheet feeding direction, of the feed roller 107. At least one of the first and second conveyance rollers 121a and 121b of the conveyance roller pair 121 is connected to a conveyance motor not shown via a drive transmission portion, and the rollers convey the sheet P received from the feed roller 107 to the upper direction.
The duplex guide 122 is arranged between the cassette 103 and the openable cover 124, and a surface on the side of the openable cover 124 and a surface on the side of the cassette 103 are both formed as guide surfaces. In the duplex guide 122, a vertical-path guide surface 122b, i.e., second guide surface, opposing to the openable cover 124 forms a part of the vertical path 126 extending along the vertical direction between a guide surface 124a, i.e., first guide surface, of the openable cover 124. A feeding-path guide surface 122a, i.e., third guide surface, facing to a guide surface 125a provided on the sheet feed frame 125 while forming a feeding path 128, is provided on an opposite side from the vertical-path guide surface 122b of the duplex guide 122. The feeding-path guide surface 122a is formed in a smoothly curved manner from an upper right direction, i.e., feeding direction by the feed roller 107, to an upper direction, i.e., conveyance direction by the conveyance roller pair 121, and the sheet P sent from the feed roller 107 is guided toward the conveyance roller pair 121. An upper end portion of the duplex guide 122 is positioned below the conveyance roller pair 121, and the feeding path 128 and the vertical path 126 are merged at a position below a nip portion of the conveyance roller pair 121. In other words, the feeding-path guide surface 122a formed in a curved manner when seen from a sheet width direction orthogonal to the conveyance direction of the sheet is connected to a downstream end of the vertical-path guide surface 122b at a downstream end.
As illustrated in
The duplex guide 122 is a pivotal guide, i.e., swing guide, provided pivotally (swingably) in a left-and-right direction around a guide shaft 122c disposed on a pivot axis located in a lower part, i.e., upstream part in the conveyance direction, of the duplex guide 122. A fixing portion 122e is provided on both end portions in a width direction, i.e., perpendicular direction to the page of
Next, a sheet feeding operation of the sheet feeding apparatus 100C configured as above will be described. When a command to feed a sheet from a control unit in the apparatus body 201A to the sheet feeding apparatus 100C is received, the sheet feed motor and a conveyance motor (both are not shown) are started, and the sheet feeding operation is started. An uppermost sheet P supported on the cassette 103 is retained at a predetermined height by having the tray 105 raised by the tray lifting plate 109.
When the rotation of the sheet feed motor is entered to the sheet feed drive shaft 107A, the feed roller 107, the separation roller 108 and the pickup roller 102 respectively start to rotate, while the elevating plate 111 is lowered to a position where the pickup roller 102 reaches the sheet feeding position. When the pickup roller 102 reaches the sheet feeding position and contacts the uppermost sheet P, the uppermost sheet P is picked up and conveyed toward the feed roller 107, and the sheet P is further conveyed by the feed roller 107 via the feeding path 128 toward the conveyance roller pair 121. At this time, the reverse rotation inputted to the separation roller 108 prevents a plurality of sheets P from entering between the feed roller 107 and the separation roller 108, that is, prevents duplex feeding.
When the sheet P sent from the feed roller 107 reaches the conveyance roller pair 121, the sheet P is conveyed upward through the vertical path 126 by the conveyance roller pair 121. The sheet P is further conveyed via the conveyance roller pairs 121 of the first and second sheet feeding apparatuses 100A and 100B, reaches the registration roller pair 240, and supplied to the image forming unit 201B. Further, the sheet conveyance unit 104 of the sheet feeding apparatus 100C also operates when the sheet P is fed from a sheet feeding apparatus disposed below. That is, the sheet conveyance unit 104 of the sheet feeding apparatus 100C conveys the sheet P sent via the conveyance roller pair 121 of the sheet feeding apparatus 100D to the upper direction. Thereby, the duplex guide 122 guides the sheet P conveyed from the sheet feeding apparatus 100D in the vertical-path guide surface 122b, i.e., second guide surface, and the sheet P conveyed from the sheet feeding apparatus 100C in the feeding-path guide surface 122a respectively to the image forming portion. The cassette 103 of the sheet feeding apparatus 100C is an example of a first sheet storage portion positioned in a lower portion of the image forming portion, and the cassette 103 of the sheet feeding apparatus 100D is an example of a second sheet storage portion positioned below the first sheet storage portion.
Next, a regulation mechanism 130 regulating the pivoting of the duplex guide 122 will be described in detail. The regulation mechanism 130 includes, as illustrated in
The abutment portions 122d, which are abutment surfaces for the stopper 123, are disposed on both sides of the duplex guide 122 in the width direction of the sheet P and disposed within a range of a conveyance area of the vertical-path guide surface 122b, as illustrated in
The vertical-path guide surface 122b is formed so that guide ribs 122h, i.e., ribs extending along a sheet feeding direction (vertical direction of
The stoppers 123, i.e., regulation portions, are fixed to a body frame 203, i.e., frame body of the apparatus body 201A, and arranged at positions capable of abutting against the abutment portions 122d, as illustrated in
The cross-sectional shapes of the abutment portion 122d and the stopper 123 will be described with reference to
As illustrated in
The stopper 123 includes a contact surface 123a opposing to the abutment portion 122d, and the contact surface 123a is formed to be inclined at a matching angle with the inclined surface d2 so as to be in surface contact with the inclined surface d2 of the abutment portion 122d (refer to
Next, the operation of the duplex guide 122 formed as above during the switching of the openable cover 124 between the open state and the close state will be described. As described, when the openable cover 124 is in the close state (
In this state, when the openable cover 124 is opened toward the right direction, that is, in the direction of arrow A1 of
When a closing operation of switching the openable cover 124 from an open state to a close state, i.e., pivoting operation to the left direction, is performed, the duplex guide 122 comes into contact with the openable cover 124 at the fixing portion 122e, and pivots toward the left along with the pivoting of the openable cover 124. At this time, the abutment portions 122d of the regulation mechanism 130 and the contact surfaces 123a of the stoppers 123 are separated. When the openable cover 124 reaches a position in the close state, the fixing portion 122e is sandwiched between the openable cover 124 and the sheet feed frame 125 again, by which the duplex guide 122 is fixed, and the sheet conveyance unit 104 will be in a state capable of conveying the sheet P.
According to the present embodiment, the duplex guide 122 of the sheet conveyance unit 104 pivots toward the outer side of the apparatus body 201A along with the opening operation of the openable cover 124. Therefore, members arranged on an inner side of the duplex guide 122 are exposed and can be accessed easily by opening the openable cover 124. In the present embodiment, the duplex guide 122 and the sheet feed frame 125 are separated when the openable cover 124 is opened, so that the sheet P and the like caught in the feeding path 128 can be removed easily, for example. Further, the duplex guide 122 is kept from pivoting beyond a predetermined angle by the regulation mechanism 130, so that the duplex guide 122 will not interfere with other members.
In a sheet conveyance unit 104 configured as above, the abutment portion 122d of the regulation mechanism 130 according to the present embodiment is formed in a depressed manner from the vertical-path guide surface 122b of the duplex guide 122. Therefore, the sheet P conveyed through the vertical path 126 can be prevented from coming into contact with the abutment portion 122d. This configuration reduces the chance of conveyance failure in which the sheet P is caught at a part of conveyance path, even when the abutment portions 122d abut against the stoppers 123 during the opening and closing operation of the openable cover 124, and damages such as scratch marks are formed on the abutment portions 122d.
Here, it is conceivable to adopt another configuration, as a first comparative example regarding the present embodiment, where an abutment portion is provided outside the conveyance area of the vertical-path guide surface 122b. That is, this comparative example includes the duplex guide 122 having abutment portions formed as projected portions projecting outward in the width direction of the dashed line A-A or the dashed line B-B of
However, according to this comparative configuration, the abutment portion protrudes to the outer side of the conveyance area of the duplex guide 122, so that the space occupied by the duplex guide 122 will become greater in the width direction as compared to the present embodiment. As a result, the size of the apparatus may become larger. On the other hand, according to the duplex guide 122 of the present embodiment, the abutment portions 122d are provided within the conveyance area of the vertical-path guide surface 122b, and the stoppers 123 are similarly provided within the conveyance area of the guide surface 124a of the openable cover 124. In other words, the regulation mechanism 130 of the present embodiment is disposed using a portion of, the vertical path 126 through which the sheet P passes, so as to minimize increase in size of the apparatus even when providing the regulation mechanism 130.
Further, an example of providing regulation portions in a vicinity of the pivot shaft of the duplex guide 122 is considered as a second comparative example regarding the present embodiment. That is, this comparative example adopts a configuration where cam members are attached to the guide shaft 122c, and regulation members are provided regulating the pivoting movement of the guide shaft by being engaged with the cam members when the duplex guide 122 reaches a predetermined angle. According to this configuration, it may be possible to suppress the occupation space of the duplex guide from being increased, while preventing the sheet P from getting caught by the scratch marks and the like formed on the abutment portion.
However, according to this configuration, when the user touches the duplex guide 122 when removing the sheet P, for example, the moment applied on the duplex guide 122 will be received at an area close to the pivot shaft. Then, a large force is applied on the cam member and the regulation member, so that measures must be taken such as providing a plurality of cam members and regulation members to prevent the apparatus from being damaged. In this case, the configuration of the apparatus may become complex and the size of the apparatus may be increased, thereby causing increase of the related costs. On the other hand, the stoppers 123 according to the present embodiment is configured to abut against the abutment portions 122d at positions between the guide shaft 122c provided at a lower portion of the duplex guide 122 and the upper end portion of the duplex guide 122. Therefore, the required strength of the abutment portions 122d and the stoppers 123 will be small as compared to the second comparative example, and a simpler configuration is adopted as compared to the second comparative example, while preventing the sheet P from getting caught without increasing the space occupied by the duplex guide.
The vertical-path guide surface 122b according to the present embodiment includes the flat surface 122p and the guide ribs 122h formed in a projected manner on the flat surface 122p, and the abutment portions 122d formed in a depressed manner on the flat surface 122p. In other words, the abutment portions 122d are further dented from the flat surface 122p that is arranged at a lower, i.e., depressed, position with respect to a tip portion of the guide ribs 122h. Thereby, the sheet P can be prevented from coming into contact with the abutment portions 122d more reliably.
Further, the abutment portions 122d according to the present embodiment are provided at a lower side than the center position in the vertical direction of the vertical-path guide surface 122b. Therefore, the stoppers 123 can be provided at a position closer to the position of the vertical-path guide surface 122b in the close state as compared to a case where the angle of regulation of pivoting of the duplex guide 122 is the same but the abutment portions 122d are provided at an upper side than the center position in the vertical direction of the vertical-path guide surface 122b. Thus, the size of the apparatus in the pivoting direction of the duplex guide 122, i.e., left-and-right direction of
Next, a modified example of the sheet feeding apparatus 100C according to the present embodiment will be described with reference to
The lifting slope 122s is provided upstream, i.e., lower side, in the sheet feeding direction of the abutment portion 122d and overlaps with the abutment portion 122d in the width direction, as illustrated in
In the sheet feeding apparatus 100C according to this modified example, when the sheet P conveyed upward through the vertical path 126 passes an end portion in the width direction of the vertical-path guide surface 122b, the sheet P passes the lifting slope 122s before passing the position corresponding to the abutment portion 122d. In the present example, the height difference between the abutment portion 122d and the vertical-path guide surface 122b arranged on the upstream side of the abutment portion is set greater by a height corresponding to the height of the stepped portion s2 of the lifting slope 122s as compared to the above-described embodiment, so that it becomes possible to more reliably prevent the sheet P from being in contact with the abutment portion 122d. Therefore, even if the sheet P is curled in the width direction or in the sheet feeding direction, the present modified example is able to prevent the sheet P from being in contact with the abutment portion 122d and assures the conveyance performance of the sheet P more reliably, in addition to the effects of the above-described embodiment.
In the illustrated embodiment, the sheet conveyance unit 104 is configured as a portion of the sheet feeding apparatus 100C, but it is also possible to provide the conveyance unit as a sheet conveyance apparatus, such as a reverse conveyance unit 201D, conveying the sheet P independently from the sheet feeding apparatus. In that case, the guide member is not necessarily configured to have both sides set as guide surfaces, such as in the case of the duplex guide 122, and the guide member should merely at least have a guide surface on the side opposing to the cover member.
Further, the openable cover 124 is provided pivotally in the left-and-right directions around the cover pivot shaft 124b disposed on the lower portion of the cover, but the pivot axis of the cover can be provided at the upper portion or the side portion. As another example, a slide-type cover member can be provided instead of the pivotable openable cover 124, or the cover may be a cover member that can be detached from the apparatus body 201A. In conclusion, any cover member can be adopted as long as it can be switched between a close state covering a portion of the apparatus body 201A and an open state exposing the duplex guide 122, i.e., guide member.
The duplex guide 122, i.e., guide member, is not restricted to a member pivoting along the left-and-right directions, but can adopt a configuration where the guide member is supported pivotally along the up-and-down directions for example. The guide member, i.e., duplex guide 122, according to the present embodiment adopts a configuration where it pivots in the outer direction of the apparatus body 201A along with the opening operation of the openable cover 124, but the guide member can also adopt a configuration where it pivots after the cover member has been switched from the close state to the open state. Moreover, the embodiment is not restricted to a configuration where the guide member pivots by its own weight, but the guide member can adopt a configuration where it pivots by receiving biasing force from a biasing member such as a coil spring.
Further, the stopper 123, i.e., regulation portion, is not restricted to a configuration where it is provided integrally with the exterior cover 127, but can be an independent member fixed to the apparatus body 201A. As long as the regulation portion regulates the pivoting of the guide member by being in contact with the abutment member in a state where the regulation portion is supported on the apparatus body 201A at least when the cover member is in the open state, a portion or all of the regulation portion can be designed to move with respect to the apparatus body.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2015-156177, filed on Aug. 6, 2015, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2015-156177 | Aug 2015 | JP | national |
