Patent Grant
8857812
1. Field of the Invention
The present invention relates to a sheet feeder having a manual feed tray, and to an image forming apparatus including the sheet feeder.
2. Description of the Related Art
Image forming apparatuses such as a copying machine, a printer, and a facsimile machine include an image forming section that forms a toner image on a sheet of paper (sheet) and a paper feeder that feeds a sheet of paper to the image forming section. Generally, an image forming apparatus includes both a paper feeder that feeds a sheet of paper from a paper cassette to the image forming section and a paper feeder that feeds a sheet of paper from a manual feed tray on which the sheet of paper is mounted by a user to the image forming section.
As a conventional image forming apparatus, an apparatus is known in which a manual feed tray is provided on a front cover of an apparatus main body and an opening operation for pulling down the manual feed tray from the front cover is to be performed in two stages. Accordingly, an impact caused when pulling down the manual feed tray is suppressed. As a result, an impact sound is suppressed and, at the same time, an impact acting on components of the manual feed tray is suppressed.
However, in the conventional image forming apparatus, the manual feed tray and the front cover are coupled by a link lever. Therefore, when a large load acts on a sheet mounting surface of the manual feed tray in a state where the manual feed tray is assuming an open posture, the load is transferred to the front cover via the link lever. Therefore, the front cover may open inadvertently.
A paper conveying path for conveying a sheet of paper is provided on a rear face of the front cover which faces the inside of the apparatus main body. A plurality of conveying rollers is arranged on the paper conveying path. Each of the plurality of conveying rollers is in contact at a predetermined contact pressure with a corresponding conveying roller arranged on the side of the apparatus main body. Therefore, when the front cover inadvertently opens due to the load, an impact generated upon the opening of the front cover may disrupt a contact pressure balance between the conveying rollers and may create a gap between the conveying rollers. Disruption of contact pressure balance causes paper conveyance failure. In addition, the impact generated upon the opening of the front cover may damage components such as the link lever.
An object of the present invention is to provide a paper feeder capable of suppressing inconveniences such as damage to parts or paper conveyance failure which may occur due to a load acting on a manual feed tray, and an image forming apparatus including the paper feeder.
In order to achieve the object described above, a paper feeder according to an aspect of the present invention includes: a housing; a sheet feeding mechanism that is arranged in the housing and that feeds a sheet in a predetermined direction; a manual feed tray that has a sheet mounting surface on which the sheet to be fed is mounted and that is pivotably mounted to the housing, the manual feed tray being configured to assume a first posture in which the manual feed tray becomes closed with respect to the housing, and to pivot and assume a second posture in which the manual feed tray becomes open with respect to the housing when in use during which the sheet is mounted on the sheet mounting surface; a link member that couples the housing with the manual feed tray, the link member being pivotably mounted to the housing and pivoting in accordance with a pivoting movement of the manual feed tray to hold the second posture of the manual feed tray; a posture changing mechanism that permits the manual feed tray to pivot further in an opening direction from the second posture when a load acts on the sheet mounting surface in a state where the manual feed tray is assuming the second posture, and that causes the manual feed tray to assume a third posture while the manual feed tray is held by the link member; and a posture holding mechanism that holds the third posture of the manual feed tray.
In addition, an image forming apparatus according to another aspect of the present invention includes: an apparatus main body; an image forming section that is arranged in the apparatus main body and that forms an image on a sheet; a cover member that is provided so as to be openable and closeable with respect to the apparatus main body and that has a sheet conveying path for conveying the sheet to the image forming section; and a sheet feeder that feeds the sheet to the image forming section and that is configured as described above, wherein a first conveying roller for conveying the sheet is provided on the sheet conveying path, and a second conveying roller that contacts the first conveying roller at a predetermined contact pressure is arranged on the apparatus main body.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The image forming apparatus 1 has an approximately box-shaped housing structure and includes an apparatus main body 2 (housing) having an internal space (an internal paper ejecting section 24). The apparatus main body 2 performs an image forming process on a sheet of paper (sheet). The apparatus main body 2 includes an approximately cuboid lower housing 21, an approximately cuboid upper housing 22 arranged above the lower housing 21, and a coupling housing 23 that couples the lower housing 21 with the upper housing 22. Various devices for forming an image are housed in the lower housing 21, and various devices for optically reading a document image are housed in the upper housing 22. An internal space enclosed by the lower housing 21, the upper housing 22, and the coupling housing 23 constitutes the internal paper ejecting section 24 capable of housing the sheet of paper after image formation. The coupling housing 23 is arranged on the side of a right side face of the apparatus main body 2 and is provided with an ejecting outlet 961 for ejecting the sheet of paper to the internal paper ejecting section 24.
The internal space that is used as the internal paper ejecting section 24 is opened to the outside at the front face and the left side face of the apparatus main body 2. The user can reach in from these open portions to retrieve the sheet of paper after image formation from the internal paper ejecting section 24. A bottom face 241 of the internal space is defined by an upper face of the lower housing 21. Sheets of paper ejected from the ejecting outlet 961 are to be stacked on the bottom face 241.
An operating panel unit 25 is provided on a front face of the upper housing 22 so as to protrude therefrom. The operating panel unit 25 includes operating keys such as a numerical keypad and a start key as well as an LCD touch panel or the like, and accepts input of various operation instructions from the user. The user is able to input the number of sheets of paper to be printed or input a print lightness/darkness setting or the like using the operating panel unit 25. An automatic document feeder ADF (not shown in
A paper feeding cassette 211 that houses sheets of paper on which an image forming process is to be performed is mounted to the lower housing 21. The paper feeding cassette 211 can be pulled out frontward from a front face of the lower housing 21. The paper feeding cassette 211 is a cassette provided for automatic paper feeding.
A paper feeder M (sheet feeder) that enables a user to perform manual paper feeding is mounted to the right side face of the apparatus main body 2. The paper feeder M includes a manual feed tray 30 on which a manually-fed sheet of paper is mounted, and a paper feeding mechanism 40 (sheet feeding mechanism) for conveying the manually-fed sheet of paper to a secondary transfer section 98 inside the lower housing 21.
A side face cover 20 (cover member) is mounted to the right side face of the apparatus main body 2 so as to be openable/closeable with respect to the apparatus main body 2 at pivot points located in a lower end part of the side face cover 20. When subjected to a downward pull-down force having a gripping part 20a as a gripping part, the side face cover 20 pivots around the pivot points and changes to an open state. The side face cover 20 is set to an open state during maintenance of the image forming apparatus 1 or the like. The manual feed tray 30 of the paper feeder M is mounted at a lower end part thereof to the side face cover 20 so as to be both openable/closeable and pivotable. When performing manual paper feeding, the user grips a gripping part 30a and pulls the manual feed tray 30 downward to set the manual feed tray 30 to an open state, and mounts a sheet of paper onto the manual feed tray 30. The paper feeder M will be described in detail with reference to
Next, an internal structure of the apparatus main body 2 will be described with reference to
For the purpose of forming a full-color toner image, the image forming unit 93 includes four image forming units 10Y, 10M, 10C, and 10Bk which respectively form toner images of yellow (Y), magenta (M), cyan (C), and black (Bk). Each of the image forming units 10Y, 10M, 10C, and 10Bk include a photosensitive drum 11, as well as a charger 12, a developing device 13, a primary transfer roller 14, and a cleaning device 15 arranged around the photosensitive drum 11.
The photosensitive drum 11 rotates around an axis thereof, and an electrostatic latent image and a toner image are formed on a circumferential surface of the photosensitive drum 11. A photosensitive drum using an amorphous silicon (a-Si)-based material can be used as the photosensitive drum 11. The charger 12 uniformly charges the surface of the photosensitive drum 11. After charging, the circumferential surface of the photosensitive drum 11 is exposed by the exposure unit 94 to form an electrostatic latent image.
The developing device 13 supplies toner to the circumferential surface of the photosensitive drum 11 in order to develop the electrostatic latent image formed on the photosensitive drum 11. The developing device 13 is for a two-component developer and includes agitating rollers 16 and 17, a magnetic roller 18, and a developing roller 19. The agitating rollers 16 and 17 charge a toner by circulating and conveying the two-component developer while applying agitation. A circumferential surface of the magnetic roller 18 bears a two-component developer layer, and a circumferential surface of the developing roller 19 bears a toner layer formed when toner is transferred due to a difference in potential between the magnetic roller 18 and the developing roller 19. Toner on the developing roller 19 is supplied to the circumferential surface of the photosensitive drum 11 to develop the electrostatic latent image.
The primary transfer roller 14 forms a nip section together with the photosensitive drum 11 with an intermediate transfer belt 921 of the intermediate transfer unit 92 in-between, and performs a primary transfer of a toner image on the photosensitive drum 11 onto the intermediate transfer belt 921. The cleaning device 15 cleans the circumferential surface of the photosensitive drum 11 after toner image transfer.
A yellow toner container 99Y, a magenta toner container 99M, a cyan toner container 99C, and a black toner container 99Bk store toners of respective colors, and supply the toners of respective colors to developing devices 13 of the image forming units 10Y, 10M, 10C, and 10Bk corresponding to the respective YMCBk colors via supply paths (not shown).
The exposure unit 94 includes a light source and various optical devices such as a polygon mirror, a reflective mirror, and a deflecting mirror, and irradiates light based on image data of a document image on a circumferential surface of a photosensitive drum 11 provided at each of the image forming units 10Y, 10M, 10C, and 10Bk to form an electrostatic latent image.
The intermediate transfer unit 92 includes the intermediate transfer belt 921, a driving roller 922, and a driven roller 923. Toner images from the plurality of photosensitive drums 11 are overcoated on the intermediate transfer belt 921 (primary transfer). Secondary transfer of the overcoated toner images is performed by the secondary transfer section 98 onto a sheet of paper supplied from the paper feeding cassette 211 or the manual feed tray 30. The driving roller 922 and the driven roller 923 which revolvingly drive the intermediate transfer belt 921 are rotatably supported by the lower housing 21. The intermediate transfer unit 92, the image forming unit 93, the exposure unit 94, and the secondary transfer section 98 constitute an image forming section.
The paper feeding cassette 211 houses a paper stack in which a plurality of sheets of paper is stacked on top of each other. A pick-up roller 212 is arranged on an upper part of a right end of the paper feeding cassette 211. Due to driving of the pick-up roller 212, an uppermost sheet of paper of the paper stack in the paper feeding cassette 211 is fed one by one and sent into an inward conveying path 26. On the other hand, a sheet of paper mounted on the manual feed tray 30 is sent into the inward conveying path 26 by the paper feeding roller 41 of the paper feeding mechanism 40 and a separation pad 47.
A paper conveying path 28 that reaches the ejecting outlet 961 via the secondary transfer section 98 and a fixing unit 97 and a paper ejecting unit 96 to be described later is provided on a downstream side of the inward conveying path 26. An upstream portion of the paper conveying path 28 is formed between an inner wall formed on the lower housing 21 and an inner wall that forms an inside face of a reverse conveying unit 29. A resist roller pair 27 is arranged on an upstream side of the paper conveying path 28 at a position further upstream than the secondary transfer section 98. A sheet of paper is temporarily stopped at the resist roller pair 27, and after being subjected to skew correction, the sheet of paper is sent out to the secondary transfer section 98 at a predetermined timing for image transfer.
In addition, a reverse conveying path 291 that conveys a sheet of paper in reverse during duplex printing is provided from the paper ejecting unit 96 to a vicinity of the resist roller pair 27. One side of the reverse conveying path 291 is constituted by an outside face of the reverse conveying unit 29, and another side of the reverse conveying path 291 is constituted by an inner wall face of the side face cover 20 which faces the inside of the lower housing 21. A plurality of conveying rollers (first conveying rollers) 292 is arranged along the reverse conveying path 291 on the inner wall face of the side face cover 20, and a plurality of conveying rollers (second conveying rollers) 293 that contacts corresponding conveying rollers 292 at a predetermined contact pressure is arranged on the outer face of the reverse conveying unit 29.
The fixing unit 97 and the paper ejecting unit 96 are housed inside the coupling housing 23. The fixing unit 97 includes a fixing roller and a pressure roller, and performs a fixing process by heating and pressurizing a sheet of paper onto which a toner image has been transferred by secondary transfer by the secondary transfer section 98. The sheet of paper with a color image which has been subjected to the fixing process is ejected by the paper ejecting unit 96 arranged on a downstream side of the fixing unit 97 from the ejecting outlet 961 toward the internal paper ejecting section 24.
A first contact glass 222 and a second contact glass 223 are fitted into the upper face of the upper housing 22. The first contact glass 222 is provided for reading a document sheet automatically fed from the automatic document feeder ADF (
A scanning mechanism 224 and an imaging element 225 for optically reading document information are housed inside the upper housing 22. The scanning mechanism 224 includes a light source, a moving carriage, a reflective mirror, and the like, and guides light reflected off of a document to the imaging element 225. The imaging element 225 photoelectrically converts the reflected light into an analog electric signal. The analog electric signal is converted into a digital electric signal by an A/D converter circuit (not shown) and input to the exposure unit 94.
The paper feeder M and, in particular, the manual feed tray 30, will now be described with reference to
As shown in
As shown in
The first flat plate 31 is a plate-like member extending in a front-rear direction of the image forming apparatus 1 (a width direction of a sheet of paper mounted on the manual feed tray 30). The first flat plate 31 faces the inside of the apparatus main body 2 when the manual feed tray 30 is assuming the first posture shown in
The second flat plate 32 is a plate-like member which extends in a front-rear direction of the image forming apparatus 1 and which opposes the first flat plate 31. The second flat plate 32 faces the outside of the apparatus main body 2 when the manual feed tray 30 is assuming the first posture and faces downward when the manual feed tray 30 is assuming the second posture.
The front side plate 33 couples a front edge part of the first flat plate 31 with a front edge part of the second flat plate 32. The rear side plate 34 couples a rear edge part of the first flat plate 31 with a rear edge part of the second flat plate 32.
An auxiliary tray 35 is extractably housed between the first flat plate 31 and the second flat plate 32. The auxiliary tray 35 can be extracted in an opposite direction to the apparatus main body 2 in a state where the manual feed tray 30 is assuming the second posture.
A pair of width cursors 36 is arranged on a downstream edge of the first flat plate 31 which is positioned on a downstream side in a paper feeding direction in which a sheet of paper mounted on the sheet mounting surface 31a is retrieved and fed by the paper feeding mechanism 40 (
The paper feeder M further includes a link member 50. The link member 50 couples the side face cover 20 of the apparatus main body 2 and the manual feed tray 30 to each other, and when the manual feed tray 30 has assumed the second posture in a state where a predetermined angle is formed with respect to a horizontal plane, holds the manual feed tray 30 in the second posture.
The side face cover 20 has a space for housing the manual feed tray 30 when the manual feed tray 30 is assuming the first posture. The space is defined by a housing wall part 20b (
On the other hand, the second end part 52 of the link member 50 is mounted to the rear side plate 34 of the manual feed tray 30. Specifically, an elongated engagement hole 38 that extends in an extending direction of the rear side plate 34 is formed on the rear side plate 34, and a protrusion 53 that slidably engages the engagement hole 38 is formed on the second end part 52. During the engagement, the protrusion 53 penetrates to the inside of the manual feed tray 30 past the engagement hole 38. When the link member 50 pivots with a movement of the manual feed tray 30 from the first posture to the second posture, the protrusion 53 slides inside the engagement hole 38. A length of the engagement hole 38 is set according to a pivot angle of the link member 50 so as to enable the protrusion 53 to slide in accordance with a pivoting movement of the link member 50 while engaging the engagement hole 38.
In the present embodiment, the second posture of the manual feed tray 30 is held by having the protrusion 53 of the link member 50 abut a stopper piece 56 of a posture changing mechanism T arranged inside the manual feed tray 30 instead of by having the protrusion 53 of the link member 50 abut a longitudinal edge of the engagement hole 38.
The posture changing mechanism T includes a housing section S, a spring member 55, and the stopper piece 56. The housing section S includes a first wall 39 (supporting portion) and a second wall 42.
The first wall 39 is a wall part which rises from the second flat plate 32 at a position directly underneath the supporting flat plate 37 and which extends from the rear side plate 34 in a direction approximately perpendicular to the rear side plate 34. The first wall 39 is integrally formed with the second flat plate 32 and the rear side plate 34. On the other hand, the second wall 42 is a wall part which rises from the second flat plate 32 and which extends approximately parallel to the rear side plate 34 toward an upstream side in a paper feeding direction from an end of the first wall 39 opposite to an end on the side of the rear side plate 34. The second wall 42 is integrally formed with the second flat plate 32. The spring member 55 and the stopper piece 56 are housed in a space defined by the first wall 39 and the second wall 42.
The spring member 55 (biasing mechanism/elastic member) has one end thereof supported by a face of the first wall 39 facing an upstream side in a paper feeding direction, and extends inside the housing section S along the engagement hole 38 of the rear side plate 34.
The stopper piece 56 is a block-like member fixed to another end of the spring member 55 and is therefore movable on an inner face-side of the rear side plate 34 along the engagement hole 38 with an expansion or contraction of the spring member 55. When the manual feed tray 30 assumes the second posture from the first posture, the stopper piece 56 is capable of abutting the protrusion 53 that slides inside the engagement hole 38 in accordance with a pivoting movement of the link member 50.
A biasing force of the spring member 55 is set to a level such that, in a state where the manual feed tray 30 has assumed the second posture from the first posture, the manual feed tray 30 can be prevented from further pivoting in an opening direction from the second posture due to a weight of sheets of paper mounted on the sheet mounting surface 31a (first load). Therefore, until the first load exceeds a predetermined weight, the spring member 55 holds the stopper piece 56 that is abutted by the protrusion 53 in an approximately extended state. Accordingly, the manual feed tray 30 is held in the second posture.
In addition, the biasing force of the spring member 55 is set so as to yield and cause the spring member 55 to contract when a second load that exceeds the first load acts on the sheet mounting surface 31a. Due to a contraction of the spring member 55, the manual feed tray 30 changes its posture from the second posture to the third posture.
Next, an operation when the manual feed tray 30 assumes the second posture from the first posture and an operation when the manual feed tray 30 assumes the third posture from the second posture will be described with reference to
When the manual feed tray 30 changes its posture from the first posture to the second posture as shown in
On the other hand, when the second load that exceeds the first load acts on the sheet mounting surface 31a in a state where the manual feed tray 30 is held in the second posture such as in a case where the user leans on the sheet mounting surface 31a or in a case where more than a predetermined number of sheets of paper is mounted on the sheet mounting surface 31a, the second load is transferred from the sheet mounting surface 31a to the protrusion 53 of the link member 50 and the protrusion 53 presses the stopper piece 56 and compresses the spring member 55 as shown in
As shown, using the biasing force of the spring member 55, the posture changing mechanism T both holds the manual feed tray 30 in the second posture and allows the manual feed tray 30 to change its posture from the second posture in the third posture.
Next, a configuration that holds the manual feed tray 30 in the third posture will be described with reference to
The manual feed tray 30 has a downstream-side edge part that is positioned on a downstream side as viewed in a paper feeding direction. A rising wall 43 that rises from the downstream-side edge part is formed on the downstream-side edge part. The rising wall 43 is notched in a plurality of locations (in
The paper feeding mechanism 40 includes the supporting frame 70 for supporting the paper feeding roller 41 and the separation pad 47 (
Pivot axis supporting sections 75 are integrally formed with the first side plate 73 and the second side plate 74 on the side of an upstream-side edge part 71a of the bottom wall 71. A pivoting section 44 having a shape capable of receiving the pivot axis supporting section 75 of the first side plate 73 is formed at a downstream-side end part of the front side plate 33 of the manual feed tray 30, and a pivoting section 44 having a shape capable of receiving the pivot axis supporting section 75 of the second side plate 74 is similarly formed at a downstream-side end part of the rear side plate 34 of the manual feed tray 30. The manual feed tray 30 is configured so as to be pivotable with respect to the side face cover 20 by pivoting while using the pivoting sections 44 as pivot points. The side face cover 20 is pivotable with respect to the apparatus main body 2 around a same axis as the pivoting sections 44.
A plurality of (in
Specifically, as shown in
As shown, in addition to the link member 50, by having the claw part 80 hold the protruding piece 46 in a state where the protruding piece 46 abuts the lower face 83 of the claw piece 82, the manual feed tray 30 is held in the third posture. In the present embodiment, the claw part 80 and the protruding piece 46 constitute the posture holding mechanism H that is capable of holding the manual feed tray 30 in the third posture.
In addition, since the protruding piece 46 abuts the lower face 83 of the claw piece 82, the manual feed tray 30 is prevented from further pivoting in an opening direction from the third posture. Therefore, when the user switches the manual feed tray 30 from the first posture to the second posture and mounts new sheets of paper onto the sheet mounting surface 31a, even if a second load acts on the sheet mounting surface 31a and the manual feed tray 30 assumes the third posture, the sheets of paper can be prevented from falling off the sheet mounting surface 31a.
Furthermore, since the manual feed tray 30 is capable of assuming the third posture as described above, by applying a load to the sheet mounting surface 31a and switching the manual feed tray 30 to the third posture, as shown in
With the aforementioned paper feeder M according to the present embodiment, in the event that a second load acts on the sheet mounting surface 31a when the manual feed tray 30 is assuming the second posture, the posture changing mechanism T allows the manual feed tray 30 to further pivot in an opening direction from the second posture while compressing the spring member 55, and causes the manual feed tray 30 to assume the third posture. In addition, the third posture of the manual feed tray 30 is held by the posture holding mechanism H. Therefore, the second load is received by an engagement structure of the claw part 80 and the protruding piece 46 in the posture holding mechanism H. Accordingly, the second load is suppressed from being transferred from the manual feed tray 30 to the side face cover 20 via the link member 50. As a result, the side face cover 20 is suppressed from changing to an open state due to the second load. Furthermore, a variation in contact pressure balance between the conveying rollers 292 of the side face cover 20 and the conveying rollers 293 of the reverse conveying unit 29 due to a propagation of the second load to the side face cover 20 can be suppressed. Accordingly, the occurrence of a paper conveying failure can be suppressed.
Moreover, by simply adjusting biasing force so that the spring member 55 of the posture changing mechanism T yields to the second load when the manual feed tray 30 is subjected to the second load and assumes the third posture from the second posture, the posture of the manual feed tray 30 can be smoothly changed from the second posture to the third posture.
While an example in which the link member 50 and the posture changing mechanism T are provided on a side face of the rear end of the manual feed tray 30 has been illustrated, the link member 50 and the posture changing mechanism T may alternatively be provided on a side face of the front edge of the manual feed tray 30 or on both the front edge and the rear edge of the manual feed tray 30.
With the paper feeder M and the image forming apparatus 1 including the paper feeder M according to the present invention as described above, inconveniences such as damage to parts or paper conveyance failure which may occur due to a load acting on the manual feed tray 30 can be suppressed.
This application is based on Japanese Patent application No. 2010-103527 filed in Japan Patent Office on Apr. 28, 2010, the contents of which are hereby incorporated by reference.
Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention hereinafter defined, they should be construed as being included therein.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-103527 | Apr 2010 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 6428000 | Hara et al. | Aug 2002 | B1 |
| 20060291342 | Kang | Dec 2006 | A1 |
| Number | Date | Country |
|---|---|---|
| 2001220047 | Aug 2001 | JP |
| 2009-96598 | May 2009 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20110266743 A1 | Nov 2011 | US |
