The present invention relates to a sheet conveying apparatus in which a sheet storage means is removably mountable while holding sheets, an image recording apparatus employing said sheet conveying apparatus, and an image reading apparatus employing said sheet conveying apparatus.
An image forming apparatus or an image reading apparatus, such as a printer, a copying machine, a scanner, etc., employs a sheet conveying apparatus for feeding blank sheets of recording medium such as recording paper, or originals in the form of sheet, into the apparatus while separating them one by one. A sheet conveying apparatus employs a cassette which is a sheet storage means. The cassette is in the form of a box, and can be removably mountable while holding a stack of sheets.
In the sheet conveying apparatuses shown in
When it is necessary for a user to replenish the image recording apparatus with sheets of recording medium, the user is to pull the boxy cassettes 101 and 201 out of the sheet conveying apparatuses. Then, the user is to replenish the cassettes 101 and 201 with sheets and remount the cassettes 101 and 201. As for the direction in which a cassette is mounted or removed, there are cassettes which are to be mounted or removed in the directions indicated by arrow marks A and B, respectively, which are parallel to the sheet conveyance direction, and cassettes which are to be mounted or removed in the direction intersectional to the sheet conveyance direction (direction perpendicular to sheet surface). Both types of cassette have been put into production.
In order to generate the force for conveying the sheets during a sheet conveyance operation, the stack of sheets is kept pressed against the feed roller. However, if the stack of sheets is kept pressed against the feed roller when the cassette is removed, it requires a large amount of force to pull the cassette out of the sheet conveying apparatus, making it difficult to pull the cassette out, and also, increasing the possibility that the sheets will become jammed (paper jam) when the cassette is pulled out. Further, if the feed roller is in a position in which it interferes with the stack of sheets, the possibility that the sheets will jam when the cassette is mounted is higher. As a means for eliminating the above described problems, it is a common practice to keep the feed roller separated from the stack of sheets by retracting at least one of the feed roller and pressure application plate when pulling out the cassette. In Japanese Patent No. 3302670, a paper feeding apparatus equipped with a mechanism for moving the feed roller away from the stack of sheets is disclosed.
However, a method for moving the feed roller, which receives rotational driving force, away from the stack of sheets, requires a high level of accuracy for the positioning of the feed roller, in terms of the rotational axis of the feed roller. Further, the feed roller is required to be rigid enough to withstand not only the reactive force which is generated as it conveys sheets, but also, the pressure applied by the pressure application plate. Therefore, in order to put the above described method into practical use, a complicated mechanism such as the one recorded in Patent Document 1 is necessary. In comparison, a method which retracts the pressure application plate instead of the feed roller can be easily put to practical use with the employment of a relatively simple mechanism. However, this method suffers from the following problem. That is, if the feed roller is disposed, as is the feed roller 102 shown in
The present invention was made in consideration of the above described technical problems. The primary object of the present invention is to provide a sheet conveying apparatus, an image recording apparatus, and an image reading apparatus, which are simple in structure and allow their sheet storage means to be easily mounted or dismounted, even though their sheet conveying means are fixed in position relative to their sheet storage means.
According to an aspect of the present invention, there is provided a sheet feeding apparatus comprising sheet accommodating means for accommodating a sheet, said sheet accommodating means being detachably mountable to said apparatus; feeding means for feeding the sheet from said sheet accommodating means; press-contact means for press-contacting the sheet in said sheet accommodating means to said feeding means; a guiding member for guiding said sheet accommodating means such that sheet accommodated in said sheet accommodating means is not contacted to said feeding means when said sheet accommodating means is mounted to said apparatus; moving means for moving said guiding member to bring the sheet into contact to said feeding means after said sheet accommodating means is mounted to said apparatus.
According to the present invention, it is possible to provide a sheet conveying apparatus, an image recording apparatus, and an image reading apparatus, which are simple in structure and allow their sheet storage means to be easily mounted or dismounted, even through their sheet conveying means are fixed in position relative to their sheet storage means.
These and other objects, features, and advantages of the present invention will become more apparent upon consideration of the following description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings.
Hereinafter, the preferred embodiments of the present invention will be concretely described with reference to the appended drawings. Incidentally, if a given component, section thereof, or the like in one of the drawings is the same in referential numeral or character as the component, section thereof, or the like in another drawing, they are identical or correspond to each other.
The sheet conveying apparatus is provided with a pressure application plate 4, which is a pressure applying means for pressing the sheets S stacked in the cassette 1 upon the feed roller 2. The pressure application plate 4 is disposed on the opposite side of the cassette 1 from the feed roller 2; it is disposed so that it will be above the stack of sheets S after the mounting of the cassette 1. The pressure application plate 4 is kept pressed toward the feed roller 2 by a spring 6, which is a means for applying downward pressure. The state of the pressure application plate 4 can be switched between two states: the state in which the stack of sheets S is kept pressed upon the feed roller 2 by the pressure generated by the spring 6, and the state in which the stack of sheets S is not pressed upon the feed roller 2. The sheet conveying apparatus is also provided with a pair of movable members 5, which are vertically movable and are disposed in the adjacencies of the feed roller 2. Each movable member 5 is in the form of a piece of plate or a rib, which extends in the direction intersectional to the sheet conveyance direction.
The pair of movable members 5 is movable between the contact position (top position) in which it is higher in position than the feed roller 2 and is in contact with the bottom surface of the stack of sheets, and the retract position (bottom position) in which it is lower in position than the feed roller 2 and remains separated from the bottom surface of the stack of sheets. The pair of movable members 5 is moved by a driving means such as a solenoid controlled by an unshown controlling means. The bottom wall of the cassette 1 is provided with an opening (unshown) for allowing the feed roller 2 and movable members 5 to come into contact with the bottom surface of the stack of sheets S. When the pair of movable members 5 is in the contact position, it supports the stack of sheets S against the force applied to the pressure application plate 4 by the spring 6. When the pair of movable members 5 is in the retract position, it allows the stack of sheets S to be pressed upon the feed roller 2 by the force applied to the pressure application plate 5 by the spring 6, making it possible for the stack of sheets S to be conveyed.
That is, the pressure application plate 4 and the pair of movable members 5 of the sheet conveying apparatus in this embodiment are structured to be controllable in their states so that their states can be switched between the state shown in
Incidentally, the sheet conveying apparatus in this embodiment is employable as a means for supplying objects, such as recording medium (for example, recording paper) or original, which is in the form of a sheet, to an image formation station or image reading station, in the wide range of apparatuses. For example, it is usable as the sheet conveying apparatus for a printer, a copying machine, facsimile machine, scanner, and a multi-functional machine or system made up of the combination of the preceding machines. That is, the sheet conveying apparatus in this embodiment can be employed by an image recording apparatus for recording an image on a sheet of recording medium with the use of a recording means based on image formation information, and such employment yields the same functional effects as those described above. Further, the sheet conveying apparatus in this embodiment can be employed by an image reading apparatus for reading the image formed on a sheet of recording medium, with the use of a reading means, and such employment also yields the same functional effects as those described above.
Referring to
In order to pull out the cassette 1 from the sheet conveying apparatus, the pair of movable members 5 is to be moved upward by the control operation of the controlling means to put the pair of movable members 5 again in the state shown in
In
When mounting the cassette 1, the solenoid 8 is to be excited by a signal from the control circuit 10 to move the cam 7 leftward against the resiliency of the return spring 9, as shown in
Referring to
The stack of sheets S in the cassette 1 is guided by the tapered portion 5a of each movable member 5, without coming into contact with the feed roller 2, and rests on the pair of movable members 5 as shown in
As the cassette 1 is moved into the preset operational position in the sheet conveying apparatus, that is, as the mounting of the cassette 1 is completed, the solenoid 8 is turned off by the control circuit 10. As the solenoid 8 is turned off, the cam 7 is returned to the home position by the return spring 9. As a result, the pair of movable members 5 moves downward, allowing the stack of sheets S to come into contact with the feed roller 2, as shown in
Designated by a referential numeral 10 in
Designated by a referential numeral 11 is the sheet conveying apparatus described with reference to
In the case of an image reading apparatus, an image reading station 13 is disposed in place of the image formation station 12. The image reading station reads the image on the sheet conveyed by the sheet conveying apparatus 11.
As described in the foregoing, according to the embodiments of the present invention, the sheet feeding apparatus includes sheet accommodating means for accommodating a sheet, said sheet accommodating means being detachably mountable to said apparatus; feeding means for feeding the sheet from said sheet accommodating means; press-contact means for press-contacting the sheet in said sheet accommodating means to said feeding means; a guiding member for guiding said sheet accommodating means such that sheet accommodated in said sheet accommodating means is not contacted to said feeding means when said sheet accommodating means is mounted to said apparatus; moving means for moving said guiding member to bring the sheet into contact to said feeding means after said sheet accommodating means is mounted to said apparatus.
Therefore, the sheet accommodating means can be mounted to or demounted from the apparatus without jamming of the sheet.
While the invention has been described with reference to the structures disclosed herein, it is not confined to the details set forth, and this application is intended to cover such modifications or changes as may come within the purposes of the improvements or the scope of the following claims.
This application claims priority from Japanese Patent Application No. 267909/2005 filed Sep. 15, 2005 which is hereby incorporated by reference.
Number | Date | Country | Kind |
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2005-267909 | Sep 2005 | JP | national |
This is a divisional of U.S. patent application Ser. No. 11/530,160, filed Sep. 8, 2006, and allowed Feb. 10, 2009.
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Number | Date | Country | |
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Number | Date | Country | |
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Parent | 11530160 | Sep 2006 | US |
Child | 12437918 | US |