Patent Application
20140061996
1. Field of the Invention
The present invention relates to a sheet feeding mechanism for feeding a sheet-type recording medium, and a recording apparatus having the sheet feeding mechanism.
2. Description of the Related Art
In various types of recording apparatuses, as an example of structures of sheet feeding mechanisms for feeding a stacked sheet recording medium, a mechanism of an inclined surface separation system is known. In this system, the uppermost recording medium in horizontally stacked recording mediums in a sheet cassette is fed with a sheet feeding roller, and the uppermost recording medium is separated from the lower recording medium using an inclined surface provided at the downstream side of the conveyance direction to feed the mediums one by one.
In such a sheet feeding method, for example, a structure is discussed in Japanese Patent Application Laid-Open No. 2006-225151. This structure has been made by focusing attention on the point that recording mediums stacked at an upper part may slide out of a sheet cassette due to the force to attach the sheet cassette, in which the recording medium is stacked, to the recording apparatus. In this structure, a contact member for contacting the upper surface of the recording medium to prevent the movement of the recording medium is provided in a fixed manner on a sheet cassette attachment path at the recording apparatus side.
In another structure, a structure is discussed in Japanese Patent Application Laid-Open No. 2011-63369. Japanese Patent Application Laid-Open No. 2011-63369 discusses a structure for solving a problem that, in a sheet feeding operation with a sheet feeding roller, the feeding orientation of a recording medium to be fed from recording mediums stacked on a sheet feeding cassette is displaced, and the recording medium is fed in the skewed state. In this structure, a second roller is provided at the upstream side of the sheet feeding roller with respect to the sheet feeding direction to control the orientation of the recording medium, which is likely to be deformed, from above the recording medium to stabilize the orientation of the recording medium to be fed in the sheet cassette.
In Japanese Patent Application Laid-Open No. 2011-63369, with reference to FIG. 7 in the publication, a structure having a plurality of driven rollers provided to an arm including a feeding roller is also discussed. In this structure, the sheet feeding roller and the driven rollers contact the recording medium to press the recording medium to reduce a conveyance difference between the right and left sides in the width direction of the recording medium being fed by the sheet feeding roller at the downstream side in the sheet feeding direction. This structure prevents the recording medium fed from the sheet cassette from being inclined and fed (i.e., skewed).
Meanwhile, in the inclined surface separation system, for example, as illustrated in FIGS. 7 and 8, a recording medium 108 to be fed with a sheet feeding roller 110 contacts an inclined part 111 and the recording medium 108 is curved upward and conveyed. In such a state, in a portion 108m near the curving portion of the recording medium 108 and on the conveyance extended line of the sheet feeding roller 110, portions where the recording medium is bent may exist. In such a case, as indicated by the arrows, at portions 108s at the both ends of the recording medium 110 at the leading edge side in the conveyance direction, the recording medium 110 is deformed toward the center side of the recording medium.
In other words, when the sheet feeding roller 110 rotates while pressing a center portion 108C of the uppermost recording medium 108 stacked on a stacking portion 106, the uppermost recording medium 108 is conveyed in the conveyance direction. Then, the uppermost recording medium 108 is bent around the portion 108m of the recording medium 108 as the recording medium 108 advances upward along the inclined portion 111. In this state, depending on effects of the pressure of the sheet feeding roller 110, the bent posture (see the portion 108m in FIGS. 7 and 8) near the center portion of the recording medium 108 differs from the bent posture (see the portions 108s in FIGS. 7 and 8) at the both end portions of the recording medium 108. Specifically, the vicinity of the center portion of the recording medium 108 is bent at a position closer to the inclined portion 111 than the both end portions of the recording medium 108 is. Due to the differences in the bent postures in one recording medium 108, as illustrated in FIG. 8, distortion is generated at the leading edge portion of the recording medium 108.
Generally, the distortion disappears due to the stiffness of the recording medium as the sheet feeding proceeds and as an area (area of the recording medium contacting the inclined surface) of the recording medium having arrived at the inclined surface increases.
In the state the distortion exists, if the leading edge of the recording medium 108 is held in the nip formed by a rubber portion of a conveyance roller 112 and a pinch roller 113, wrinkles are formed in the recording medium 108.
Such a phenomenon is especially likely to occur in a recording medium having low stiffness such as thin paper.
To regulate such deformed conveyance of the recording medium, the structure discussed in FIG. 7 in Japanese Patent Application Laid-Open No. 2011-63369 may be employed. The structure is, however, directed to prevention of the recording medium from being fed in an inclined state, and the driven roller always contacts the recording medium with a regulating force (urging force) for regulating the recording medium from being inclined in the sheet feeding operation. As a result, a large load is applied to the driving force for sheet feeding. Further, while the structure is effective to reduce the skew, the strong pressure by the driven roller on the recording medium may cause occurrence of a bending portion like 108m illustrated in FIG. 8 also in the driven roller portion.
Further, the contact member discussed in Japanese Patent Application Laid-Open No. 2006-225151 is not configured to control distortion in a recording medium to be fed, and the contact member is fixed to the apparatus. As a result, depending on the number of stacked sheets of the recording medium, its functions are limited. Consequently, this structure is not effective to the problems to be solved in the present invention at all.
The present invention is directed to a sheet feeding apparatus capable of reducing distortion in a recording medium in curving the recording medium fed by a sheet feeding roller along an inclined surface for separation without affecting driving force for the sheet feeding, and a recording apparatus having the sheet feeding apparatus.
According to an aspect of the present invention, a sheet feeding mechanism includes a sheet feeding roller configured to feed an uppermost recording medium from stacked recording mediums, an inclined portion located at a downstream position of the sheet feeding roller in a conveyance direction of the recording medium and having a surface inclined with respect to the conveyance direction, and a restriction member configured not to contact the recording medium before the sheet feeding roller feeds the recording medium, and configured to contact the recording medium in a state where the recording medium is fed by the sheet feeding roller and conveyed along the inclined portion.
According to another aspect of the present invention, a sheet feeding mechanism includes a sheet feeding roller configured to feed stacked sheet-type recording mediums one by one from an uppermost recording medium, with an inclined portion, and a restriction member configured not to contact the recording medium before the sheet feeding roller feeds the recording medium, and configured to contact the recording medium in a state where the recording medium is curved and fed along the inclined portion.
According to yet another aspect of the present invention, a sheet feeding mechanism includes a sheet feeding roller configured to feed stacked sheet-type recording mediums one by one from an uppermost recording medium, with an inclined portion, and a restriction member configured not to contact the recording medium before the sheet feeding roller feeds the recording medium, and provided so that a leading portion of the restriction member is to be located, after the sheet feeding roller starts to feed the recording medium, at a position closer to the inclined portion by crossing a locus of the recording medium being conveyed in a state where the recording medium curves along the inclined portion.
According to exemplary embodiments of the present invention, a restriction member is provided to reduce distortion generation in a recording medium without giving a specific sheet feeding load in a sheet feeding roller feeding the recording medium by starting contact in a state where the recording medium arrives at an inclined surface and starts to curve. By the structure, feeding a recording medium can be restricted without distortion.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
In this specification, for convenience, the expression “recording” is used to express things rendered using ink, or the like on the surface of a recording medium or things to be rendered.
Hereinafter, a first exemplary embodiment will be described.
The recording apparatus illustrated in
At the downstream position of the recording head 1 in the conveyance direction of the recording medium, a discharge roller 4 and a driven roller 5 are provided. Between the discharge roller 4 and the driven roller 5, the recording medium on which recording has been performed by the recording head 1 is held, and the recording medium is discharged with rotation of the discharge roller 4 and the driven roller 5.
The recording apparatus according to the present exemplary embodiment includes two portions for storing the recording medium. One of the portions is disposed at the bottom surface side of the recording apparatus, and the portion is a first stacking portion 6 to which a first sheet cassette for storing a first recording medium 8 is to be attached. The other one is a second stacking portion 7, which is disposed at an upper portion of the first stacking portion 6 and to which a second sheet cassette for storing a second recording medium 9 is to be attached.
At the leading portion of the first stacking portion 6 at the downstream side in the conveyance direction of the first recording medium 8, a first sheet feeding roller 10 is provided that contacts the first recording medium 8 when the first recording medium 8 is loaded, and that performs sheet feeding. The first sheet feeding roller 10 is driven to feed the first recording medium 8 stacked on the first stacking portion 6. At the downstream position of the first sheet feeding roller 10 in the conveyance direction of the first recording medium 8, a first inclined portion 11 is provided. The first inclined portion 11 includes a slope inclined upward with respect to the conveyance direction of the first recording medium 8. In recording mediums fed by the first sheet feeding roller 10, with the use of the slope of the first inclined portion 11, only the uppermost recording medium in the first recording medium 8 is separated from the other recording mediums, and fed. At an upper portion of the first inclined portion 11 and at the downstream in the conveyance direction of the recording medium, a first conveyance roller 12 and a first pinch roller 13 are provided. The recording medium fed upward along the slope of the first inclined portion 11 is conveyed by the first conveyance roller 12 and the first pinch roller 13. The conveyed recording medium is further conveyed to a recording area via a first conveyance guide 21 by a common conveyance roller 14 and a common pinch roller 15 provided further downstream than the first conveyance roller 12 and the first pinch roller 13 in the conveyance direction of the recording medium. The first conveyance roller 12, the first pinch roller 13, the first conveyance guide 21, the common conveyance roller 14, and the common pinch roller 15 constitute a first conveyance path.
Meanwhile, at the leading portion of the second stacking portion 7, disposed at the upper portion of the first stacking portion, at the downstream side in the conveyance direction of the second recording medium 9, a second sheet feeding roller 16 is provided that contacts the second recording medium 9 when the second recording medium 9 is loaded and that performs sheet feeding. At the downstream position of the second sheet feeding roller 16 in the conveyance direction of the second recording medium 9, a second inclined portion 17 is provided. The second inclined portion 17 includes, similarly to the first inclined portion 11, a slope inclined upward with respect to the conveyance direction of the second recording medium 9. At an upper portion of the second inclined portion 17 and at the downstream in the conveyance direction of the second recording medium, a second conveyance roller 18 and a second pinch roller 19 are provided. Between the second inclined portion 17 and the second conveyance roller 18, a movable member 20 that is opened or closed by the leading edge of the second recording medium 9 fed upward along the slope of the second inclined portion 17 is provided.
The conveyed recording medium is further conveyed to the recording area via a second conveyance guide 22 by the common conveyance roller 14 and the common pinch roller 15 provided further downstream than the second conveyance roller 18 and the second pinch roller 19 in the conveyance direction of the recording medium.
The second conveyance roller 18, the second pinch roller 19, the second conveyance guide 22, the common conveyance roller 14, and the common pinch roller 15 constitute a second conveyance path.
The first conveyance guide 21 and the conveyance guide 22 merge into one member in the middle of the paths, and, at the merging point, a conveyance guide member 24 is provided. The conveyance guide member 24 includes the common conveyance roller 14 and the common pinch roller 15, and the conveyance guide member 24 extends to the main conveyance roller 2. From the conveyance guide member 24, a conveyance guide member 23 is separately extended. The conveyance guide member 23 guides each of the recording medium to the conveyance roller 18 when the main conveyance roller 2 conveys the first recording medium 8 and the second recording medium 9 in the reverse direction separating from the recording head 1 (for example, in two-sided printing).
As illustrated in
In the present exemplary embodiment, the supporting member 25 can move up and down such that the first sheet feeding roller 10 can contact the uppermost first recording medium 8 according to the number of stacked sheets (stacked amount) of the first recording medium 8 stacked on the first stacking portion 6. By the structure, the restriction members 26 can move up and down similarly to the first sheet feeding roller 10.
Irrespective of the number of stacked sheets of the first recording medium 8 stacked on the first stacking portion 6, the leading portion of the restriction member 26 is located at a position nearer to the first inclined portion 11 than the first sheet feeding roller 10. Further, the leading portion of the restriction member 26 is located near the area where the plane of the uppermost first recording medium 8 intersects with the first inclined portion 11. Detailed description of the restriction members 26 will be made with reference to
Hereinafter, functions of the restriction member 26 will be described.
Before the sheet feeding of the first recording medium 8, as illustrated in
As will be understood, before the sheet feeding is performed, the restriction member 26 is in a non-contact state with respect to the first recording medium 8, and, consequently, the restriction members 26 do not affect the sheet feeding load in feeding of the first recording medium 8 by the first sheet feeding roller 10.
Then, as illustrated in
The orientation of the recording medium curved at the space between the first stacking portion 6 and the first inclined portion 11 differs depending on the stiffness of the recording medium. The restriction members 26 are configured to be thin and to effectively control occurrence of bending and distortion in a recording medium having low stiffness, and is disposed in the recording medium.
In other words, it is desirable that at the time of the start of sheet feeding operation, the restriction members 26 do not contact the recording medium, and that, after the recording medium is fed, irrespective of the type of the recording medium, in a state where the recording medium contacts the inclined portion and starts curving, the leading portions of the restriction members 26 contact the recording medium.
Alternatively, it may be defined that, to a locus of the recording medium conveyed in a state where the recording medium curves along the inclined portion after the start of the sheet feeding operation, across the locus, the leading portion of the restriction member 26 is to be located at a position closer to the inclined portion.
Further, it is desirable that the restriction members 26 are configured not to be a conveyance load while functioning as a distortion restriction structure to the conveyance of the recording medium. For example, as illustrated in
Further, it is desirable that the state of the contact portion of the restriction member contacting the recording medium is line contact. In the wide line contact state, the restriction of the recording medium can be effectively performed. In point contact, depending on the type of the recording medium, the bending occurring at 108m in
Hereinafter, bent postures of the recording medium 8 in a structure the restriction members 26 are provided to the supporting member 25 is described.
A pair of the restriction members 26 is, as described above, symmetrically disposed via the sheet feeding roller 10 in the width direction of the recording medium 8. Each of the restriction members 26 extends toward the slope to press the uppermost layer of the first recording medium 8 at a position closer to the slope of the inclined portion 11 than the first sheet feeding roller 10. By the structure, the both end portions of the first recording medium 8 out of the range the pressure of the sheet feeding roller 10 can be applied can be pressed by the restriction members 26. Consequently, as illustrated in
Meanwhile, in a sheet feeding mechanism for feeding the second recording medium, the above-described structure of the restriction members 26 can be employed.
The restriction members may not be included in a case where the recording medium stacked on the sheet feeding mechanism is a thick recording medium such as coated paper. The restriction members are to be provided to a sheet feeding mechanism stacking a recording medium having low stiffness such as plain paper.
A second exemplary embodiment of the present invention is described. Hereinafter, differences from the first exemplary embodiment are mainly described.
As illustrated in
In the above-described structure of the sheet feeding apparatus according to the present exemplary embodiment, when the leading portions of the restriction members 26 are pushed by a generated force due to bending of the recording medium 8, the restriction members 26 start to rotate around the rotation shaft 26a. In such a state, due to the elastic force of the elastic member 27, the restriction members 26 are stopped at the positions contacting the stopper 25a. As a result, the recording medium 8 is pressed by the restriction members 26 at a predetermined pressure.
In the present exemplary embodiment, similar to the first exemplary embodiment, when the leading edge of the recording medium 8 starts to move upward along the slope of the first inclined portion 11, the pair of the restriction members 26 presses the both end portions of the recording medium 8. As a result, the recording medium 8 has an even bent posture as a whole in the width direction. This prevents the leading edge of the recording medium 8 from being deformed. As a result, when the leading edge of the recording medium 8 is held by the conveyance roller 12, generation of wrinkles can be reduced.
Further, with the rotation shaft 26a, the stopper 25a, and the elastic member 27, the restriction members 26 can evenly bend the recording medium irrespective of the stiffness of the recording medium.
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. 2012-194010 filed Sep. 4, 2012, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-194010 | Sep 2012 | JP | national |
