Patent Application
20140210160
This application claims priority under 35 U.S.C. ยง119 from Japanese Patent Application No. 2013-016350 filed on Jan. 31, 2013. The entire subject matter of the application is incorporated herein by reference.
1. Technical Field
The following description relates to one or more techniques for a sheet feeder that includes a driving roller and a driven roller configured to rotate in accordance with rotation of the driving roller and feed a sheet while pinching the sheet with the driving roller.
2. Related Art
A sheet feeding mechanism has been known in which a driven roller is rotatably supported by an elastic shaft such as a contact coil spring, and is pressed against a driving roller. Further, a different sheet feeding mechanism has been known in which hooks are provided at two ends of a coil spring as an elastic shaft, and a driven roller is attached to a supporting body with the hooks of the coil spring being hung on pins provided at the supporting body.
In the known sheet feeding mechanism, the elastic shaft rotates in response to rotation of the driven roller. Therefore, undesired noises are generated when the elastic shaft comes into sliding contact with bearing portions that support both end portions in an axial direction of the elastic shaft. On the other hand, in the known different sheet feeding mechanism, it is possible to prevent rotation of the elastic shaft since the hooks of the elastic shaft are hung on the pins. However, when the driven roller is attached to the supporting body, required is a troublesome operation of hanging the hooks on the pins.
Aspects of the present invention are advantageous to provide one or more improved techniques, for a sheet feeder, which make it possible to prevent rotation of an elastic shaft and to easily attach a driven roller.
According to aspects of the present invention, a sheet feeder is provided, which includes a driving roller, a driven roller configured to rotate in accordance with rotation of the driving roller and feed a sheet while pinching the sheet with the driving roller, an elastic shaft inserted through the driven roller and configured to rotatably support the driven roller, the elastic shaft including a protrusion formed on at least one end of the elastic shaft in an axial direction of the elastic shaft, the protrusion protruding outward in a radial direction of the driven roller, and two recess-shaped bearings configured to support two end portions of the elastic shaft in the axial direction, respectively, at least one of the bearings including a contact surface configured to contact the protrusion when the elastic shaft is supported by with the bearings.
It is noted that various connections are set forth between elements in the following description. It is noted that these connections in general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect.
Hereinafter, an embodiment according to aspects of the present invention will be described with reference to the accompanying drawings. It is noted that, in the following descriptions, a front side, a rear side, a left side, a right side, an upside, and a downside will be defined as shown in the accompanying drawings.
Initially, an explanation will be provided about a general configuration of an automatic document feeder (hereinafter which may be referred to as ADF) 1 in the embodiment. The ADF 1 shown in
As shown in
Document sheets set on the feed tray 10 are fed into the document feeding unit 30 by the pickup roller 32. After separated on a sheet-by-sheet basis between the separation roller 33 and the separation nipping member 34, the document sheets are sequentially conveyed toward the first feed roller 35. Then, the document sheets are sequentially conveyed toward the reading position R while being pinched between the first feed roller 35 and the first pinch roller 36. Afterward, the document sheets are sequentially read by the image sensor 92 while passing through the reading position R, and then conveyed toward the catch tray 20 while being pinched between the second feed roller 37 and the second pinch roller 38. Thereafter, the document sheets are sequentially ejected out of the document feeding unit 30 by the ejection roller unit(s) 60, and put onto the catch tray 20.
Hereinafter, a detailed configuration of the ADF 1 will be described. The ADF 1 includes the first feed roller 35, the first pinch roller 36, and a frame 40 that is made of resin and configured to rotatably support the first feed roller 35 and the first pinch roller 36.
The first feed roller 35 is configured to be driven to rotate by a driving force from a driving source such as a motor (not shown).
The first pinch roller 36 is disposed at a lower right side of the first feed roller 35. The first pinch roller 36 is configured to be rotated in accordance with rotation of the first feed roller 35. More specifically, as shown in
Through the first pinch roller 36, an elastic shaft 60 is inserted in a rotatable manner. As shown in
The elastic shaft 60 is a coil spring. The elastic shaft 60 includes, at one end thereof (in the embodiment, at a front end thereof), a protrusion 61 protruding outward in a radial direction of the first pinch roller 36. More specifically, as shown in
As shown in
The roller compartment 110 includes two roller acceptors 111 and a joint acceptor 112. The two roller acceptors 111 are configured to accept (accommodate) the roller portions 36A of the first pinch roller 36. The joint acceptor 112 is formed to protrude from inner surfaces of the roller acceptors 111 and configured to accept (accommodate) the joint portion 36B. The first pinch roller 36, when attached to the frame 40, is positioned in the axial direction of the first pinch roller 36 by a groove-shaped recessed portion 36D engaging with the joint acceptor 112. The groove shape of the recessed portion 36D is defined by the two roller portions 36A and the joint portion 36B.
As shown in
Each concave portion 122 is disposed outside the corresponding shaft supporter 121 in the axial direction of the elastic shaft 60. Further, each concave portion 122 is formed in a shape recessed outward in the radial direction of the first pinch roller 36, more specifically, in a downward-recessed shape. The concave portions 122 are configured to face the respective end portions of the elastic shaft 60 when the elastic shaft 60 is supported by the bearings 120. Although detailed functions of the concave portions 122 will be described later, a right-side surface of surfaces forming each concave portion 122 is a contact surface 124 configured to contact the protrusion 61 of the elastic shaft 60.
Each slanted surface 123 is formed between the corresponding shaft supporter 121 and the corresponding concave portion 122. Further, each slanted surface 123 is slanted with respect to the shaft supporter so as to extend obliquely down toward a recessed region of the concave portion 122 from an outer end of the shaft supporter 121.
As shown in
Subsequently, an explanation will be provided about operations and advantageous effects of the ADF 1 configured as above. As shown in
Further, in the embodiment, the slanted surface 123 is formed between the shaft supporter 121 and the concave portion 122 of each bearing 120. Therefore, when the elastic shaft 60 is supported by the bearings 120, the protrusion 61 is put into the concave portion 122 along the slanted surface 123 (e.g., of the front-side bearing 120). Thereby, it is possible to easily attach the first pinch roller 36 no matter what direction the protrusion 61 is oriented in.
As shown in
As shown in
Further, as shown in
Thus, according to the ADF 1 of the embodiment, when the elastic shaft 60 is caused to rotate by the rotation of the first pinch roller 36, the contact between the protrusion 61 and the contact surface 124 prevents the rotation of the elastic shaft 60. Hence, it is possible to prevent generation of undesired noises due to sliding contact of the elastic shaft 60 with the bearings 120.
Further, in the embodiment, the protrusion 61 of the elastic shaft 60 is formed with such a length as not to protrude to the side of the first feed roller 35 beyond the feeding surfaces 36C of the first pinch roller 36. Therefore, it is possible to prevent contact between the protrusion 61 and the document sheet M. Thereby, it is possible to prevent undesired noises or damages of the document sheet M from being caused by the contact between the protrusion 61 and the document sheet M.
Further, in the embodiment, each bearing 120 includes the shaft supporter 121 and the concave portion 122. Hence, it is possible to let the protrusion 61 of the elastic shaft 60 get into the concave portion 122. Thereby, the shaft supporters 121 are allowed to stably support inner portions of the elastic shaft 60 relative to the ends in the axial direction of the elastic shaft 60. Thus, it is possible to stabilize a load applied to the first feed roller 35 from the elastic shaft 60 via the first pinch roller 36.
Further, in the embodiment, the two bearings 120 are formed to be mirror-symmetric with respect to a place perpendicular to the axial direction of the first pinch roller 36 (i.e., the front-to-rear direction), and have the respective contact surfaces 124. Hence, when the first pinch roller 36 is attached to the bearings 120, the user needs not pay careful attention to what direction the elastic shaft 60 is oriented in (i.e., which side of the elastic shaft 60 the protrusion 61 is provided at). Therefore, referring to
Further, in the embodiment, the protrusion 61 is formed by one end of the wire W, which is spirally coiled to form the elastic shaft 60 as a coil spring, being radially protruded outward from the spirally-coiled body of the elastic shaft 60. Therefore, it is possible to easily form the protrusion 61 at the elastic shaft 60.
Hereinabove, the embodiment according to aspects of the present invention has been described. The present invention can be practiced by employing conventional materials, methodology and equipment. Accordingly, the details of such materials, equipment and methodology are not set forth herein in detail. In the previous descriptions, numerous specific details are set forth, such as specific materials, structures, chemicals, processes, etc., in order to provide a thorough understanding of the present invention. However, it should be recognized that the present invention can be practiced without reapportioning to the details specifically set forth. In other instances, well known processing structures have not been described in detail, in order not to unnecessarily obscure the present invention.
Only an exemplary embodiment of the present invention and but a few examples of their versatility are shown and described in the present disclosure. It is to be understood that the present invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein. For example, the following modifications are possible. It is noted that, in the following modifications, explanations of the same configurations as exemplified in the aforementioned embodiments will be omitted.
In the aforementioned embodiment, each of the two bearings 120 has the contact surface 124. However, for instance, when the elastic shaft 60 has the protrusion 61 at only one end thereof in the axial direction as exemplified in the aforementioned embodiment, only one of the two bearings 120 that supports the end portion of the elastic shaft 60 at which the protrusion 61 is formed may have the contact surface 124.
In the aforementioned embodiment, the elastic shaft 60 has the protrusion 61 at only one end thereof in the axial direction. Nonetheless, for instance, the elastic shaft 60 may have the protrusion 61 at each end thereof in the axial direction. In this case, when the elastic shaft 60 is manufactured, careful attentions need to be paid to the positions of the two protrusions 61, and respective processes of forming the two protrusions 61 need to be performed at both the ends of the elastic shaft 60. However, when the elastic shaft 60 has the protrusion 61 at only one end thereof as exemplified in the aforementioned embodiment, there is no need for such careful attentions or forming processes. Thus, it is possible to more easily manufacture the elastic shaft 60 than when the elastic shaft 60 has the protrusion 61 at each end thereof
In the aforementioned embodiment, the elastic shaft 60 is a coil spring. However, for instance, the elastic shaft 60 may be a bar-shaped elastically-bendable member such as a bar spring.
Further, for instance, each bearing 120 may not have the slanted surface 123 formed between the shaft supporter 121 and the concave portion 122.
In the aforementioned embodiment with the first feed roller 35 as a driving roller and the first pinch roller 36 as a driven roller, aspects of the present invention are applied to the first pinch roller 36 and the bearings 120. However, for instance, aspects of the present invention may be applied to the second pinch roller 38 and bearings for the second pinch roller 38 in a modification with the second feed roller 37 as a driving roller and the second pinch roller 38 as a driven roller in the ADF 1 as shown in
In the aforementioned embodiment, aspects of the present invention are applied to the ADF 1. Nonetheless, for instance, aspects of the present invention may be applied to a sheet feeding mechanism for a printer or a copy machine.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-016350 | Jan 2013 | JP | national |
