US20100013144A1 - Paper feed apparatus - Google Patents
Paper feed apparatus Download PDFInfo
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- US20100013144A1 US20100013144A1 US12/496,774 US49677409A US2010013144A1 US 20100013144 A1 US20100013144 A1 US 20100013144A1 US 49677409 A US49677409 A US 49677409A US 2010013144 A1 US2010013144 A1 US 2010013144A1
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- Prior art keywords
- paper
- roller
- circumferential face
- moon roller
- moon
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G15/00—Apparatus for electrographic processes using a charge pattern
- G03G15/65—Apparatus which relate to the handling of copy material
- G03G15/6502—Supplying of sheet copy material; Cassettes therefor
- G03G15/6511—Feeding devices for picking up or separation of copy sheets
Definitions
- the present invention relates to a paper feed apparatus that is applied in an image forming apparatus such as a copier, a printer, or a facsimile apparatus, for example, and feeds recording paper or the like.
- JP S62-191337A discloses this type of conventional paper feed apparatus.
- a bottom plate on which a plurality of sheets of paper are stored in a stacked manner is biased upward, and the sheets of paper are stored in a state in which the topmost sheet of paper is abutted against a height regulating member.
- a half-moon roller disposed above the sheets of paper is rotated so that the half-circumferential face of the half-moon roller pushes against the topmost sheet of paper, and the topmost sheet of paper is pulled out by the half-circumferential face of the half-moon roller.
- an auxiliary roller is additionally provided at the end of the half-circumferential face of the half-moon roller.
- the half-circumferential face of the half-moon roller is pushed against the topmost sheet of paper and the topmost sheet of paper is pulled out by the half-circumferential face of the half-moon roller.
- the auxiliary roller which rotates together with the half-moon roller, is pushed against the topmost sheet of paper, pushing down the sheets of paper.
- FIG. 7 There is also a conventional apparatus as shown in FIG. 7 .
- an auxiliary roller 202 is provided in the vicinity of a half-circumferential face end 201 a of a half-moon roller 201 .
- the half-moon roller 201 is rotated so that the auxiliary roller 202 and the half-circumferential face of the half-moon roller 201 successively push against a topmost sheet of paper 204 , while the sheets of paper are pushed down by the auxiliary roller 202 or the half-circumferential face of the half-moon roller 201 so that the topmost sheet of paper 204 is separated downward from a height regulating member 203 , the topmost sheet of paper 204 is pulled out by the half-circumferential face of the half-moon roller 201 .
- a 90 degree corner is formed in the half-circumferential face end 201 a of the half-moon roller 201 , and because the half-circumferential face end 201 a drops precipitously, when the auxiliary roller 202 and the half-circumferential face of the half-moon roller 201 are successively pushed against the topmost sheet of paper 204 , the time during which the auxiliary roller 202 and the half-circumferential face of the half-moon roller 201 both are in contact with the topmost sheet of paper 204 is extremely short, and at about the same time that the auxiliary roller 202 separates from the topmost sheet of paper 204 , the corner of the half-circumferential face end 201 a of the half-moon roller 201 is pressed against the topmost sheet of paper 204 .
- the topmost sheet of paper 204 is static, and the topmost sheet of paper 204 is locally pushed against by the corner of the half-circumferential face end 201 a of the half-moon roller 201 , and the static frictional force between the topmost sheet of paper 204 and the sheet of paper below the sheet of paper 204 becomes very high. Therefore, paper multi-feeding occurs in which when the topmost sheet of paper 204 is pulled out by the half-circumferential face of the half-moon roller 201 , the sheet of paper below the sheet of paper 204 is also pulled out at the same time.
- the invention provides a paper feed apparatus having a half-moon roller disposed above a plurality of sheets of paper stored in a stacked manner, and an auxiliary roller provided along one end of a half-circumferential face of the half-moon roller, the half-moon roller being rotated in a state in which a topmost sheet of paper has been put in contact with a height regulating member due to the sheets of paper being biased upward, so that the auxiliary roller and the half-circumferential face of the half-moon roller are successively pushed against the topmost sheet of paper, and while the sheets of paper are pushed down by the auxiliary roller or the half-circumferential face of the half-moon roller, the topmost sheet of paper is pulled out by the half-circumferential face of the half-moon roller: the one end of the half-circumferential face of the half-moon roller being separated from the auxiliary roller, and a curvature of the one end of the half-
- the half-circumferential face of the half-moon roller is configured with a frictional face.
- the one end of the half-circumferential face of the half-moon roller is separated from the auxiliary roller, and the curvature of the one end of the half-circumferential face is gradually increased closer to the auxiliary roller, so from before the auxiliary roller separates from the topmost sheet of paper, the half-circumferential face end of the half-moon roller gradually starts to be pushed against the topmost sheet of paper, thus increasing the time that both the auxiliary roller and the end of the half-circumferential face of the half-moon roller are in contact with the topmost sheet of paper.
- the restoring force in the upward direction of the sheets of paper is received in a dispersed manner at the auxiliary roller and the end of the half-circumferential face of the half-moon roller, and the static frictional force between the topmost sheet of paper and the sheet of paper below the topmost sheet of paper decreases.
- pulling out of the topmost sheet of paper by the end of the half-circumferential face of the half-moon roller is started, and only this topmost sheet of paper is quickly pulled out, so paper multi-feeding is unlikely to occur.
- FIG. 1 is a cross-sectional view that shows an image forming apparatus in which one embodiment of a paper feed apparatus of the invention is applied.
- FIG. 2 is a cross-sectional view that shows the paper feed apparatus of this embodiment.
- FIG. 3 is a cross-sectional view that shows an enlarged view of the vicinity of a half-moon roller in the paper feed apparatus in FIG. 2 .
- FIG. 4 is a cross-sectional view that shows a state in which the half-moon roller in the paper feed apparatus in FIG. 2 has rotated approximately 90 degrees in the counter-clockwise direction.
- FIG. 5 is a cross-sectional view that shows a further enlarged view of the vicinity of one end of the half-moon roller and an auxiliary roller.
- FIG. 6 shows a process of displacement of the surface of a topmost sheet of paper relative to the half-moon roller and the auxiliary roller.
- FIG. 7 is a cross-sectional view that shows an enlarged view of the vicinity of a half-moon roller in a conventional paper feed apparatus.
- FIG. 8 is a cross-sectional view that shows a state in which the half-moon roller in the paper feed apparatus in FIG. 7 has rotated approximately 90 degrees in the counter-clockwise direction.
- FIG. 1 is a schematic view that shows an image forming apparatus in which one embodiment of a paper feed apparatus of the invention is applied.
- This image forming apparatus acquires image data that has been read from an original, or acquires image data that has been received from outside, and forms a monochrome image represented by this image data on paper.
- this configuration includes an automatic document feeder (ADF) 101 , an original reading apparatus 102 , a printer unit 103 , a paper transport unit 104 , and a paper feed apparatus 105 .
- ADF automatic document feeder
- the automatic document feeder 101 when an original of at least one sheet is placed on an original placement tray 11 , the original is pulled out from the original placement tray 11 sheet by sheet and conveyed so that this original is guided to and passed over a first glass platen 14 of the original reading apparatus 102 , and then the original is discharged to a discharge tray 12 .
- an optical unit including a first scanning unit 15 and a second scanning unit is disposed below the first glass platen 14 , and when the original passes over the first glass platen 14 , the original surface is exposed to light by a light source of the first scanning unit 15 , reflected light from the original surface is guided to an imaging lens 17 by mirrors of the first scanning unit 15 and the second scanning unit 16 , and an image of the original surface is formed on a CCD (Charge Coupled Device) 18 by the imaging lens 17 .
- the CCD 18 repeatedly reads the image of the original surface in a main scanning direction, and outputs image data that represents the image of the original surface.
- the original surface on the second glass platen 19 is exposed to light by the first scanning unit 15 , reflected light from the original surface is further reflected and guided to the imaging lens 17 by the first scanning unit 15 and the second scanning unit 16 , and an image of the original surface is formed on the CCD 18 by the imaging lens 17 .
- the first scanning unit 15 and the second scanning unit 16 are moved while maintaining a predetermined speed relative to each other, so that the positional relationship of the first scanning unit 15 and the second scanning unit 16 is always maintained such that the length of a light path of reflected light, i.e., from the original surface to the first and second scanning units 15 and 16 to the imaging lens 17 to the CCD 18 , does not change, and thus focus of the image of the original surface on the CCD 18 is always precisely maintained.
- the image data is output to the printer unit 103 .
- an original transport system in which an original is conveyed on the first glass platen 14 , and an original fixed system in which an original is placed on the second glass platen 19 , and then the optical unit (the first scanning unit 15 and the second scanning unit 16 ) is moved, are both employed.
- a photosensitive drum 4 is disposed in approximately the middle of the printer unit 103 , and around the photosensitive drum 4 are disposed a charging unit 5 , an optical scanning unit 6 , a development unit 7 , a transfer unit 8 , and a cleaning unit 9 .
- a fixing apparatus 20 is disposed in the upper part of the printer unit 103 .
- the fixing apparatus 20 receives paper on which an image has been transferred, and sandwiching that paper between a fixing roller and a pressure roller, fixes the developed image that has been transferred onto the paper.
- This paper is conveyed upward by a transport roller, and discharged to a discharge tray 22 from a discharge roller 21 .
- the paper when forming an image on both faces of paper, the paper is reverse-conveyed in the opposite direction by the discharge roller 21 , and further conveyed to a reverse transport path 23 , and after reversing the front and back sides of that paper, the paper is again conveyed to the printer unit 103 , and a developed image is transferred and fixed to the back side of that paper. Then the paper is discharged from the discharge roller 21 to the discharge tray 22 .
- the paper feed apparatus 105 is provided with a paper feed cassette 24 . Paper is separated and supplied sheet by sheet from the paper feed cassette 24 , and supplied between the photosensitive drum 4 and the transfer unit 8 , where the developed image on the photosensitive drum 4 is transferred to this paper.
- the paper feed cassette 24 is supported so as to be capable of sliding to the front side of the body of the image forming apparatus.
- the paper feed cassette 24 is pulled out to the front side, and a batch of paper is stored stacked on a bottom plate 31 inside of the paper feed cassette 24 .
- a rear edge regulating member 32 supported so as to be capable of moving left-right in FIG. 2 is provided on the floor of the paper feed cassette 24 .
- the front edge of the paper batch on the bottom plate 31 is put in contact with an inner wall face 24 a of the paper feed cassette 24 , the rear edge regulating member 32 is moved until abutting against the rear edge of the paper batch on the bottom plate 31 , and the paper batch on the bottom plate 31 is positioned sandwiched between the inner wall face 24 a and the rear edge regulating member 32 . Also, both sides of the paper batch are positioned sandwiched by a pair of guide members (not shown) provided so as to be movable on the floor of the paper feed cassette 24 .
- the bottom plate 31 is axially supported by a shaft 31 a , and is biased in the counter-clockwise direction around the shaft 31 a by an unshown spring.
- the paper batch on the bottom plate 31 is raised upward until a topmost sheet of paper 25 on the bottom plate 31 makes contact with a height regulating member 33 .
- a half-moon roller 34 is disposed above the front end side of the bottom plate 31 and is axially supported, and is driven so as to rotate in the counter-clockwise direction around a shaft 35 .
- An auxiliary roller 36 is additionally provided at one end of the half-circumferential face of the half-moon roller 34 .
- the half-moon roller 34 When the half-moon roller 34 is driven so as to rotate in the counter-clockwise direction, first the auxiliary roller 36 presses against the topmost sheet of paper 25 on the bottom plate 31 , and while the auxiliary roller 36 rolls on the topmost sheet of paper 25 , the paper batch on the bottom plate 31 is pushed downward against the spring restoring force, so that the topmost sheet of paper 25 is separated downward from the height regulating member 33 . Next, the half-circumferential face of the half-moon roller 34 presses against the topmost sheet of paper 25 , and the topmost sheet of paper 25 is pulled out by the half-circumferential face of the half-moon roller 34 .
- FIG. 3 is a cross-sectional view that shows an enlarged view of the vicinity of the half-moon roller 34 .
- FIG. 4 is a cross-sectional view that shows a state in which the half-moon roller 34 has rotated approximately 90 degrees in the counter-clockwise direction.
- FIG. 5 is a cross-sectional view that shows a further enlarged view of the vicinity of one end of the half-moon roller 34 and the auxiliary roller 36 .
- the half-moon roller 34 as shown in FIGS. 3 to 5 includes a frame body 41 and a friction rubber 42 .
- the frame body 41 is fixed to the shaft 35 , and the friction rubber 42 is overlaid on the half-circumferential face of the frame body 41 .
- Both ends 42 a of the friction rubber 42 are fixed by hooking to respective engaging recesses 41 a on both sides of the frame body 41 .
- the outside surface of the friction rubber 42 serves as a half-circumferential face 34 a of the half-moon roller 34 , and part of the friction rubber 42 becomes one end 34 b of the half-circumferential face 34 a.
- the rotatable auxiliary roller 36 is linked to an end 41 b of the frame body 41 by an unshown linking structure, and the auxiliary roller 36 is disposed separated from the end 34 b of the half-moon roller 34 .
- the half-circumferential face 34 a of the half-moon roller 34 except for the one end 34 b of the half-circumferential face 34 a , traces a circular arc around the shaft 35 (shown in FIGS. 3 and 4 ). Also, an outermost circumferential position 36 p of the auxiliary roller 36 is on a rotational trajectory S where the half-circumferential face 34 a of the half-moon roller 34 rotates around the shaft 35 , or in the vicinity of the rotational trajectory S.
- the half-circumferential face 34 a Assuming that the one end 34 b (part of the friction rubber 42 ) of the half-circumferential face 34 a is a portion on the right side from a position 34 p , the half-circumferential face 34 a traces a circular arc around the shaft 35 on the left side from the position 34 p , and the one end 34 b of the half-circumferential face 34 a is formed on the right side from the position 34 p such that a curvature R of that circular arc gradually increases at positions closer to the auxiliary roller 36 . Thus the one end 34 b of the half-circumferential face 34 a is formed so as to be enveloped to the inside.
- the topmost sheet of paper is biased upward to always be pressed against the half-moon roller 34 or the auxiliary roller 36 , so as shown in FIG. 6 , the half-moon roller 34 and the auxiliary roller 36 are successively displaced relative to the surface 25 a of the topmost sheet of paper.
- the half-moon roller 34 and the auxiliary roller 36 are successively displaced relative to the surface 25 a of the topmost sheet of paper.
- the solid line indicates a state in which only the auxiliary roller 36 is pressed against the surface 25 a of the topmost sheet of paper
- the dotted line indicates a state in which the one end 34 b of the half-circumferential face 34 a of the half-moon roller 34 and the auxiliary roller 36 are pressed against the surface 25 a of the topmost sheet of paper
- the double-dotted chained line indicates a state in which only the half-circumferential face 34 a of the half-moon roller 34 is pressed against the surface 25 a of the topmost sheet of paper.
- the one end 34 b which has a large curvature R, of the half-circumferential face 34 a is pressed against the surface 25 a of the topmost sheet of paper.
- the half-moon roller 34 further rotates so that the half-circumferential face 34 a on the left side from the position 34 p presses against the surface 25 a of the topmost sheet of paper, and until the auxiliary roller 36 separates from the surface 25 a of the topmost sheet of paper, the one end 34 b , which has a large curvature R, of the half-circumferential face 34 a continues to press against the surface 25 a of the topmost sheet of paper.
- the one end 34 b which has a large curvature R, of the half-circumferential face 34 a continues to press against the surface 25 a of the topmost sheet of paper.
- the auxiliary roller 36 While the one end 34 b , which has a large curvature R, of the half-circumferential face 34 a continues to press against the surface of the topmost sheet of paper, the auxiliary roller 36 also is pressing against the surface of the topmost sheet of paper, so the contact area of the half-circumferential face 34 a and the auxiliary roller 36 with the surface of the topmost sheet of paper increases, and the spring restoring force that pushes up the paper batch on the bottom plate 31 is dispersed, and thus the contact force of the one end 34 b of the half-circumferential face 34 a against the surface of the topmost sheet of paper decreases.
- the static frictional force between the topmost sheet of paper and the sheet of paper below the topmost sheet of paper decreases, so the topmost sheet of paper is easily pulled away from the sheet of paper below by the one end 34 b of the half-circumferential face 34 a , and thus conveyance of the topmost sheet of paper starts quickly.
- a smaller kinetic frictional force occurs between the topmost sheet of paper and the sheet of paper below the topmost sheet of paper, so pulling out of the topmost sheet of paper by the half-circumferential face 34 a of the half-moon roller 34 is reliably continued. As a result, only the topmost sheet of paper is pulled out, and paper multi-feeding does not occur.
- the extent to which the curvature R of the one end 34 b of the half-moon roller 34 increases may be appropriately changed.
- the invention is applicable not only to a paper feed tray that stores printing paper in a stacked manner, but also to an original tray that stores original paper in a stacked manner.
Abstract
In one embodiment of the invention, in a paper feed apparatus having a half-moon roller disposed above a plurality of sheets of paper stored in a stacked manner, and an auxiliary roller provided along one end of a half-circumferential face of the half-moon roller, the half-moon roller being rotated in a state in which a topmost sheet of paper has been put in contact with a height regulating member due to the sheets of paper being biased upward, so that the auxiliary roller and the half-circumferential face of the half-moon roller are successively pushed against the topmost sheet of paper, and while the sheets of paper are pushed down by the auxiliary roller or the half-circumferential face of the half-moon roller, the topmost sheet of paper is pulled out by the half-circumferential face of the half-moon roller: the one end of the half-circumferential face of the half-moon roller is separated from the auxiliary roller, and a curvature of the one end of the half-circumferential face is gradually increased closer to the auxiliary roller.
Description
- This application claims priority under 35 U.S.C. §119(a) on Patent Application No. 2008-185078 filed in Japan on Jul. 16, 2008, the entire contents of which are herein incorporated by reference.
- The present invention relates to a paper feed apparatus that is applied in an image forming apparatus such as a copier, a printer, or a facsimile apparatus, for example, and feeds recording paper or the like.
- JP S62-191337A discloses this type of conventional paper feed apparatus. Here, a bottom plate on which a plurality of sheets of paper are stored in a stacked manner is biased upward, and the sheets of paper are stored in a state in which the topmost sheet of paper is abutted against a height regulating member. A half-moon roller disposed above the sheets of paper is rotated so that the half-circumferential face of the half-moon roller pushes against the topmost sheet of paper, and the topmost sheet of paper is pulled out by the half-circumferential face of the half-moon roller.
- Also, in the disclosure of JP H5-286585A, an auxiliary roller is additionally provided at the end of the half-circumferential face of the half-moon roller. By rotating the half-moon roller, the half-circumferential face of the half-moon roller is pushed against the topmost sheet of paper and the topmost sheet of paper is pulled out by the half-circumferential face of the half-moon roller. When the half-circumferential face of the half-moon roller is separated from the topmost sheet of paper, the auxiliary roller, which rotates together with the half-moon roller, is pushed against the topmost sheet of paper, pushing down the sheets of paper.
- There is also a conventional apparatus as shown in
FIG. 7 . In this apparatus, anauxiliary roller 202 is provided in the vicinity of a half-circumferential face end 201a of a half-moon roller 201. As shown inFIG. 8 , the half-moon roller 201 is rotated so that theauxiliary roller 202 and the half-circumferential face of the half-moon roller 201 successively push against a topmost sheet ofpaper 204, while the sheets of paper are pushed down by theauxiliary roller 202 or the half-circumferential face of the half-moon roller 201 so that the topmost sheet ofpaper 204 is separated downward from aheight regulating member 203, the topmost sheet ofpaper 204 is pulled out by the half-circumferential face of the half-moon roller 201. - Various conventional apparatuses that employ a half-moon roller in this way have been provided.
- Incidentally, in the conventional apparatus in
FIGS. 7 and 8 , a 90 degree corner is formed in the half-circumferential face end 201 a of the half-moon roller 201, and because the half-circumferential face end 201 a drops precipitously, when theauxiliary roller 202 and the half-circumferential face of the half-moon roller 201 are successively pushed against the topmost sheet ofpaper 204, the time during which theauxiliary roller 202 and the half-circumferential face of the half-moon roller 201 both are in contact with the topmost sheet ofpaper 204 is extremely short, and at about the same time that theauxiliary roller 202 separates from the topmost sheet ofpaper 204, the corner of the half-circumferential face end 201 a of the half-moon roller 201 is pressed against the topmost sheet ofpaper 204. At this time, the topmost sheet ofpaper 204 is static, and the topmost sheet ofpaper 204 is locally pushed against by the corner of the half-circumferential face end 201 a of the half-moon roller 201, and the static frictional force between the topmost sheet ofpaper 204 and the sheet of paper below the sheet ofpaper 204 becomes very high. Therefore, paper multi-feeding occurs in which when the topmost sheet ofpaper 204 is pulled out by the half-circumferential face of the half-moon roller 201, the sheet of paper below the sheet ofpaper 204 is also pulled out at the same time. - The present invention was made in consideration of the above problems, and it is an object thereof to provide a paper feed apparatus in which paper multi-feeding does not occur in a configuration in which an auxiliary roller is provided at an end of a half-circumferential face of a half-moon roller.
- In order to address the above problems, the invention provides a paper feed apparatus having a half-moon roller disposed above a plurality of sheets of paper stored in a stacked manner, and an auxiliary roller provided along one end of a half-circumferential face of the half-moon roller, the half-moon roller being rotated in a state in which a topmost sheet of paper has been put in contact with a height regulating member due to the sheets of paper being biased upward, so that the auxiliary roller and the half-circumferential face of the half-moon roller are successively pushed against the topmost sheet of paper, and while the sheets of paper are pushed down by the auxiliary roller or the half-circumferential face of the half-moon roller, the topmost sheet of paper is pulled out by the half-circumferential face of the half-moon roller: the one end of the half-circumferential face of the half-moon roller being separated from the auxiliary roller, and a curvature of the one end of the half-circumferential face being gradually increased closer to the auxiliary roller. Also, in the paper feed apparatus with the above configuration, before the auxiliary roller separates from the surface of the topmost sheet of paper, the one end of the half-circumferential face of the half-moon roller having a large curvature presses against the surface of the topmost sheet of paper. Further, in the paper feed apparatus with the above configuration, the half-circumferential face of the half-moon roller is configured with a frictional face. Furthermore, in the paper feed apparatus with the above configuration, the half-moon roller is configured from a frame body that has been fixed to a shaft that serves as a rotational center of the half-moon roller, and a friction rubber that has been overlaid on the half-circumferential face of the frame body, the auxiliary roller being rotatably linked to one end of the frame body, and the half-circumferential face of the half-moon roller is the outside surface of the friction rubber, and the one end of the half-circumferential face of the half-moon roller is part of the friction rubber.
- According to the invention having this sort of configuration, the one end of the half-circumferential face of the half-moon roller is separated from the auxiliary roller, and the curvature of the one end of the half-circumferential face is gradually increased closer to the auxiliary roller, so from before the auxiliary roller separates from the topmost sheet of paper, the half-circumferential face end of the half-moon roller gradually starts to be pushed against the topmost sheet of paper, thus increasing the time that both the auxiliary roller and the end of the half-circumferential face of the half-moon roller are in contact with the topmost sheet of paper. Therefore, the restoring force in the upward direction of the sheets of paper is received in a dispersed manner at the auxiliary roller and the end of the half-circumferential face of the half-moon roller, and the static frictional force between the topmost sheet of paper and the sheet of paper below the topmost sheet of paper decreases. In this state, pulling out of the topmost sheet of paper by the end of the half-circumferential face of the half-moon roller is started, and only this topmost sheet of paper is quickly pulled out, so paper multi-feeding is unlikely to occur.
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FIG. 1 is a cross-sectional view that shows an image forming apparatus in which one embodiment of a paper feed apparatus of the invention is applied. -
FIG. 2 is a cross-sectional view that shows the paper feed apparatus of this embodiment. -
FIG. 3 is a cross-sectional view that shows an enlarged view of the vicinity of a half-moon roller in the paper feed apparatus inFIG. 2 . -
FIG. 4 is a cross-sectional view that shows a state in which the half-moon roller in the paper feed apparatus inFIG. 2 has rotated approximately 90 degrees in the counter-clockwise direction. -
FIG. 5 is a cross-sectional view that shows a further enlarged view of the vicinity of one end of the half-moon roller and an auxiliary roller. -
FIG. 6 shows a process of displacement of the surface of a topmost sheet of paper relative to the half-moon roller and the auxiliary roller. -
FIG. 7 is a cross-sectional view that shows an enlarged view of the vicinity of a half-moon roller in a conventional paper feed apparatus. -
FIG. 8 is a cross-sectional view that shows a state in which the half-moon roller in the paper feed apparatus inFIG. 7 has rotated approximately 90 degrees in the counter-clockwise direction. - Hereinafter, an embodiment of the invention will be described in detail with reference to the attached drawings.
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FIG. 1 is a schematic view that shows an image forming apparatus in which one embodiment of a paper feed apparatus of the invention is applied. This image forming apparatus, acquires image data that has been read from an original, or acquires image data that has been received from outside, and forms a monochrome image represented by this image data on paper. Broadly speaking, this configuration includes an automatic document feeder (ADF) 101, anoriginal reading apparatus 102, aprinter unit 103, apaper transport unit 104, and apaper feed apparatus 105. - In the
automatic document feeder 101, when an original of at least one sheet is placed on anoriginal placement tray 11, the original is pulled out from the original placement tray 11 sheet by sheet and conveyed so that this original is guided to and passed over afirst glass platen 14 of theoriginal reading apparatus 102, and then the original is discharged to adischarge tray 12. - In the
original reading apparatus 102, an optical unit including afirst scanning unit 15 and a second scanning unit is disposed below thefirst glass platen 14, and when the original passes over thefirst glass platen 14, the original surface is exposed to light by a light source of thefirst scanning unit 15, reflected light from the original surface is guided to animaging lens 17 by mirrors of thefirst scanning unit 15 and thesecond scanning unit 16, and an image of the original surface is formed on a CCD (Charge Coupled Device) 18 by theimaging lens 17. TheCCD 18 repeatedly reads the image of the original surface in a main scanning direction, and outputs image data that represents the image of the original surface. - Also, when an original has been placed on a
second glass platen 19 on the upper face of theoriginal reading apparatus 102, while moving thefirst scanning unit 15 and thesecond scanning unit 16 in a sub-scanning direction, the original surface on thesecond glass platen 19 is exposed to light by thefirst scanning unit 15, reflected light from the original surface is further reflected and guided to theimaging lens 17 by thefirst scanning unit 15 and thesecond scanning unit 16, and an image of the original surface is formed on theCCD 18 by theimaging lens 17. At this time, thefirst scanning unit 15 and thesecond scanning unit 16 are moved while maintaining a predetermined speed relative to each other, so that the positional relationship of thefirst scanning unit 15 and thesecond scanning unit 16 is always maintained such that the length of a light path of reflected light, i.e., from the original surface to the first andsecond scanning units imaging lens 17 to theCCD 18, does not change, and thus focus of the image of the original surface on theCCD 18 is always precisely maintained. - After a control circuit of a microcomputer or the like performs various image processing on the image data that has been output from the
CCD 18, the image data is output to theprinter unit 103. - Accordingly, in the
original reading apparatus 102 of this embodiment, an original transport system in which an original is conveyed on thefirst glass platen 14, and an original fixed system in which an original is placed on thesecond glass platen 19, and then the optical unit (thefirst scanning unit 15 and the second scanning unit 16) is moved, are both employed. - A
photosensitive drum 4 is disposed in approximately the middle of theprinter unit 103, and around thephotosensitive drum 4 are disposed a charging unit 5, anoptical scanning unit 6, adevelopment unit 7, atransfer unit 8, and acleaning unit 9. - The charging unit 5 uniformly charges the surface of the
photosensitive drum 4. Theoptical scanning unit 6 inputs image data, and while modulating the strength of an optical beam according to the image data, scans the optical beam on the uniformly chargedphotosensitive drum 4 to write an electrostatic latent image on thephotosensitive drum 4. Thedevelopment unit 7 develops the electrostatic latent image on thephotosensitive drum 4 using a developer, thus forming a developed image on thephotosensitive drum 4. Thetransfer unit 8, while conveying paper sandwiched between thetransfer unit 8 and thephotosensitive drum 4, transfers the developed image on thephotosensitive drum 4 onto paper. Thecleaning unit 9 removes developer remaining on thephotosensitive drum 4, making it possible to form a new developed image on thephotosensitive drum 4. - A
fixing apparatus 20 is disposed in the upper part of theprinter unit 103. Thefixing apparatus 20 receives paper on which an image has been transferred, and sandwiching that paper between a fixing roller and a pressure roller, fixes the developed image that has been transferred onto the paper. - This paper is conveyed upward by a transport roller, and discharged to a
discharge tray 22 from a discharge roller 21. - Also, when forming an image on both faces of paper, the paper is reverse-conveyed in the opposite direction by the discharge roller 21, and further conveyed to a
reverse transport path 23, and after reversing the front and back sides of that paper, the paper is again conveyed to theprinter unit 103, and a developed image is transferred and fixed to the back side of that paper. Then the paper is discharged from the discharge roller 21 to thedischarge tray 22. - The
paper feed apparatus 105 is provided with apaper feed cassette 24. Paper is separated and supplied sheet by sheet from thepaper feed cassette 24, and supplied between thephotosensitive drum 4 and thetransfer unit 8, where the developed image on thephotosensitive drum 4 is transferred to this paper. - Next is a detailed description of the
paper feed apparatus 105 of this embodiment with reference toFIG. 2 . In thispaper feed apparatus 105, thepaper feed cassette 24 is supported so as to be capable of sliding to the front side of the body of the image forming apparatus. Thepaper feed cassette 24 is pulled out to the front side, and a batch of paper is stored stacked on abottom plate 31 inside of thepaper feed cassette 24. A rearedge regulating member 32 supported so as to be capable of moving left-right inFIG. 2 is provided on the floor of thepaper feed cassette 24. The front edge of the paper batch on thebottom plate 31 is put in contact with aninner wall face 24 a of thepaper feed cassette 24, the rearedge regulating member 32 is moved until abutting against the rear edge of the paper batch on thebottom plate 31, and the paper batch on thebottom plate 31 is positioned sandwiched between theinner wall face 24 a and the rearedge regulating member 32. Also, both sides of the paper batch are positioned sandwiched by a pair of guide members (not shown) provided so as to be movable on the floor of thepaper feed cassette 24. - Furthermore, the
bottom plate 31 is axially supported by ashaft 31 a, and is biased in the counter-clockwise direction around theshaft 31 a by an unshown spring. The paper batch on thebottom plate 31 is raised upward until a topmost sheet ofpaper 25 on thebottom plate 31 makes contact with aheight regulating member 33. - A half-
moon roller 34 is disposed above the front end side of thebottom plate 31 and is axially supported, and is driven so as to rotate in the counter-clockwise direction around ashaft 35. Anauxiliary roller 36 is additionally provided at one end of the half-circumferential face of the half-moon roller 34. - When the half-
moon roller 34 is driven so as to rotate in the counter-clockwise direction, first theauxiliary roller 36 presses against the topmost sheet ofpaper 25 on thebottom plate 31, and while theauxiliary roller 36 rolls on the topmost sheet ofpaper 25, the paper batch on thebottom plate 31 is pushed downward against the spring restoring force, so that the topmost sheet ofpaper 25 is separated downward from theheight regulating member 33. Next, the half-circumferential face of the half-moon roller 34 presses against the topmost sheet ofpaper 25, and the topmost sheet ofpaper 25 is pulled out by the half-circumferential face of the half-moon roller 34. - Similarly thereafter, each time that the half-
moon roller 34 makes one rotation in the counter-clockwise direction, the topmost sheet ofpaper 25 is pushed away from theheight regulating member 33 by theauxiliary roller 36, and the topmost sheet ofpaper 25 is pulled out by the half-circumferential face of the half-moon roller 34. -
FIG. 3 is a cross-sectional view that shows an enlarged view of the vicinity of the half-moon roller 34.FIG. 4 is a cross-sectional view that shows a state in which the half-moon roller 34 has rotated approximately 90 degrees in the counter-clockwise direction.FIG. 5 is a cross-sectional view that shows a further enlarged view of the vicinity of one end of the half-moon roller 34 and theauxiliary roller 36. - The half-
moon roller 34 as shown inFIGS. 3 to 5 includes aframe body 41 and afriction rubber 42. Theframe body 41 is fixed to theshaft 35, and thefriction rubber 42 is overlaid on the half-circumferential face of theframe body 41. Both ends 42a of thefriction rubber 42 are fixed by hooking to respective engagingrecesses 41 a on both sides of theframe body 41. The outside surface of thefriction rubber 42 serves as a half-circumferential face 34 a of the half-moon roller 34, and part of thefriction rubber 42 becomes oneend 34 b of the half-circumferential face 34 a. - The rotatable
auxiliary roller 36 is linked to anend 41 b of theframe body 41 by an unshown linking structure, and theauxiliary roller 36 is disposed separated from theend 34 b of the half-moon roller 34. - In
FIG. 5 , the half-circumferential face 34 a of the half-moon roller 34, except for the oneend 34 b of the half-circumferential face 34 a, traces a circular arc around the shaft 35 (shown inFIGS. 3 and 4 ). Also, an outermostcircumferential position 36 p of theauxiliary roller 36 is on a rotational trajectory S where the half-circumferential face 34 a of the half-moon roller 34 rotates around theshaft 35, or in the vicinity of the rotational trajectory S. - Assuming that the one
end 34 b (part of the friction rubber 42) of the half-circumferential face 34 a is a portion on the right side from a position 34 p, the half-circumferential face 34 a traces a circular arc around theshaft 35 on the left side from the position 34 p, and the oneend 34 b of the half-circumferential face 34 a is formed on the right side from the position 34 p such that a curvature R of that circular arc gradually increases at positions closer to theauxiliary roller 36. Thus the oneend 34 b of the half-circumferential face 34 a is formed so as to be enveloped to the inside. - When this sort of half-
moon roller 34 is rotationally driven in the counter-clockwise direction together with theauxiliary roller 36, as previously described, theauxiliary roller 36 presses against asurface 25 a of the topmost sheet of paper, and while theauxiliary roller 36 rolls on thesurface 25 a of the topmost sheet of paper, the paper batch on thebottom plate 31 is pushed downward against the spring restoring force. - At this time, the topmost sheet of paper is biased upward to always be pressed against the half-
moon roller 34 or theauxiliary roller 36, so as shown inFIG. 6 , the half-moon roller 34 and theauxiliary roller 36 are successively displaced relative to thesurface 25 a of the topmost sheet of paper. InFIG. 6 , the solid line indicates a state in which only theauxiliary roller 36 is pressed against thesurface 25 a of the topmost sheet of paper, the dotted line indicates a state in which the oneend 34 b of the half-circumferential face 34 a of the half-moon roller 34 and theauxiliary roller 36 are pressed against thesurface 25 a of the topmost sheet of paper, and the double-dotted chained line indicates a state in which only the half-circumferential face 34 a of the half-moon roller 34 is pressed against thesurface 25 a of the topmost sheet of paper. - As is clear from
FIG. 6 , before theauxiliary roller 36 is separated from thesurface 25 a of the topmost sheet of paper, the oneend 34 b, which has a large curvature R, of the half-circumferential face 34 a is pressed against thesurface 25 a of the topmost sheet of paper. - Then, the half-
moon roller 34 further rotates so that the half-circumferential face 34 a on the left side from the position 34 p presses against thesurface 25 a of the topmost sheet of paper, and until theauxiliary roller 36 separates from thesurface 25 a of the topmost sheet of paper, the oneend 34 b, which has a large curvature R, of the half-circumferential face 34 a continues to press against thesurface 25 a of the topmost sheet of paper. - Accordingly, for a predetermined period before the
auxiliary roller 36 separates from thesurface 25 a of the topmost sheet of paper, the oneend 34 b, which has a large curvature R, of the half-circumferential face 34 a continues to press against thesurface 25 a of the topmost sheet of paper. - While the one
end 34 b, which has a large curvature R, of the half-circumferential face 34 a continues to press against the surface of the topmost sheet of paper, theauxiliary roller 36 also is pressing against the surface of the topmost sheet of paper, so the contact area of the half-circumferential face 34 a and theauxiliary roller 36 with the surface of the topmost sheet of paper increases, and the spring restoring force that pushes up the paper batch on thebottom plate 31 is dispersed, and thus the contact force of the oneend 34 b of the half-circumferential face 34 a against the surface of the topmost sheet of paper decreases. Therefore, the static frictional force between the topmost sheet of paper and the sheet of paper below the topmost sheet of paper decreases, so the topmost sheet of paper is easily pulled away from the sheet of paper below by the oneend 34 b of the half-circumferential face 34 a, and thus conveyance of the topmost sheet of paper starts quickly. Immediately after the start of conveyance, only a smaller kinetic frictional force occurs between the topmost sheet of paper and the sheet of paper below the topmost sheet of paper, so pulling out of the topmost sheet of paper by the half-circumferential face 34 a of the half-moon roller 34 is reliably continued. As a result, only the topmost sheet of paper is pulled out, and paper multi-feeding does not occur. - Above, a preferred embodiment of the invention was described with reference to the attached figures, but of course the invention is not limited by that example. It will be clear to a person having ordinary skill in the art that within the category described in the claims, various modified or revised examples can be arrived at, and it will be understood by a person having ordinary skill in the art that that such examples also are naturally encompassed by the technical scope of the invention.
- For example, the extent to which the curvature R of the one
end 34 b of the half-moon roller 34 increases may be appropriately changed. Also, the invention is applicable not only to a paper feed tray that stores printing paper in a stacked manner, but also to an original tray that stores original paper in a stacked manner. - The present invention may be embodied in various other forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed in this application are to be considered in all respects as illustrative and not limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all modifications or changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.
Claims (4)
1. A paper feed apparatus having a half-moon roller disposed above a plurality of sheets of paper stored in a stacked manner, and an auxiliary roller provided along one end of a half-circumferential face of the half-moon roller, the half-moon roller being rotated in a state in which a topmost sheet of paper has been put in contact with a height regulating member due to the sheets of paper being biased upward, so that the auxiliary roller and the half-circumferential face of the half-moon roller are successively pushed against the topmost sheet of paper, and while the sheets of paper are pushed down by the auxiliary roller or the half-circumferential face of the half-moon roller, the topmost sheet of paper is pulled out by the half-circumferential face of the half-moon roller:
the one end of the half-circumferential face of the half-moon roller being separated from the auxiliary roller, and a curvature of the one end of the half-circumferential face being gradually increased closer to the auxiliary roller.
2. The paper feed apparatus according to claim 1 ,
wherein before the auxiliary roller separates from the surface of the topmost sheet of paper, the one end of the half-circumferential face of the half-moon roller having a large curvature presses against the surface of the topmost sheet of paper.
3. The paper feed apparatus according to claim 1 ,
wherein the half-circumferential face of the half-moon roller comprises a frictional face.
4. The paper feed apparatus according to claim 1 ,
wherein the half-moon roller comprises a frame body that has been fixed to a shaft that serves as a rotational center of the half-moon roller, and a friction rubber that has been overlaid on the half-circumferential face of the frame body, the auxiliary roller being rotatably linked to one end of the frame body, and
the half-circumferential face of the half-moon roller is the outside surface of the friction rubber, and the one end of the half-circumferential face of the half-moon roller is part of the friction rubber.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2008-185078 | 2008-07-16 | ||
JP2008185078A JP2010023956A (en) | 2008-07-16 | 2008-07-16 | Paper feed apparatus |
Publications (1)
Publication Number | Publication Date |
---|---|
US20100013144A1 true US20100013144A1 (en) | 2010-01-21 |
Family
ID=41529601
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/496,774 Abandoned US20100013144A1 (en) | 2008-07-16 | 2009-07-02 | Paper feed apparatus |
Country Status (3)
Country | Link |
---|---|
US (1) | US20100013144A1 (en) |
JP (1) | JP2010023956A (en) |
CN (1) | CN101630130B (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8511672B2 (en) * | 2011-08-22 | 2013-08-20 | Canon Kabushiki Kaisha | Sheet feeding apparatus and image forming apparatus |
US9302866B1 (en) * | 2015-02-24 | 2016-04-05 | Lexmark International, Inc. | Pick mechanism pick roll tire having multiple tread widths |
EP3161806A4 (en) * | 2014-06-27 | 2018-03-07 | Digital Check Corporation | Automatic document alignment |
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US3866903A (en) * | 1971-10-30 | 1975-02-18 | Agfa Gevaert Ag | Sheet feeding apparatus |
US4437656A (en) * | 1978-08-29 | 1984-03-20 | Canon Kabushiki Kaisha | Sheet feeding device |
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JPS5554249U (en) * | 1978-10-09 | 1980-04-12 | ||
JPS5623134A (en) * | 1979-07-31 | 1981-03-04 | Canon Inc | Sheet feeder |
JP3323802B2 (en) * | 1998-03-11 | 2002-09-09 | キヤノン株式会社 | Paper feeder and image forming apparatus having the same |
JP4115945B2 (en) * | 2004-01-09 | 2008-07-09 | シャープ株式会社 | Paper feeding device and image forming apparatus |
KR100692573B1 (en) * | 2005-08-31 | 2007-03-13 | 삼성전자주식회사 | Print Media Supply Device for Image Forming Apparatus |
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2008
- 2008-07-16 JP JP2008185078A patent/JP2010023956A/en active Pending
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2009
- 2009-07-02 US US12/496,774 patent/US20100013144A1/en not_active Abandoned
- 2009-07-15 CN CN2009101403013A patent/CN101630130B/en not_active Expired - Fee Related
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US3866903A (en) * | 1971-10-30 | 1975-02-18 | Agfa Gevaert Ag | Sheet feeding apparatus |
US4437656A (en) * | 1978-08-29 | 1984-03-20 | Canon Kabushiki Kaisha | Sheet feeding device |
US5326184A (en) * | 1992-10-26 | 1994-07-05 | Hewlett-Packard Company | Apparatus and method for picking paper from a stack |
US5954328A (en) * | 1996-07-09 | 1999-09-21 | Mita Industrial Co., Ltd. | Paper feed mechanism |
JPH115641A (en) * | 1997-06-16 | 1999-01-12 | Canon Inc | Drive transmitting device, feeder and image forming device |
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JPH11334903A (en) * | 1998-05-22 | 1999-12-07 | Canon Inc | Sheet feeding device and image forming device therewith |
US6341774B1 (en) * | 1999-07-16 | 2002-01-29 | Ricoh Company, Ltd. | Sheet feeding device having gap regulating member to avoid double feeding of sheets and image forming apparatus using feeding device |
US20060180988A1 (en) * | 2004-10-28 | 2006-08-17 | Mamoru Yorimoto | Device for feeding a recording medium at a controlled distance and image forming apparatus having such device |
US20080012203A1 (en) * | 2006-02-10 | 2008-01-17 | Bdt Ag | Feed roller, feed roller assembly, and sheet handling system |
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Cited By (3)
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US8511672B2 (en) * | 2011-08-22 | 2013-08-20 | Canon Kabushiki Kaisha | Sheet feeding apparatus and image forming apparatus |
EP3161806A4 (en) * | 2014-06-27 | 2018-03-07 | Digital Check Corporation | Automatic document alignment |
US9302866B1 (en) * | 2015-02-24 | 2016-04-05 | Lexmark International, Inc. | Pick mechanism pick roll tire having multiple tread widths |
Also Published As
Publication number | Publication date |
---|---|
CN101630130B (en) | 2012-06-27 |
JP2010023956A (en) | 2010-02-04 |
CN101630130A (en) | 2010-01-20 |
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