JP3826026B2 - Sheet feeding device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet feeding apparatus for supplying sheets to an image forming apparatus such as a printer, a facsimile machine, and a copying machine.
[0002]
[Prior art]
FIG. 9 is a cross-sectional view of an apparatus main body 100 of a laser printer that is an image forming apparatus.
[0003]
This laser printer includes a cassette feeding device that is detachable from the apparatus main body 100 and has a sheet feeding cassette 50 as a stacking means for sheets P. The cassette feeding apparatus includes a sheet feeding roller 5 provided on the apparatus main body 100, and a sheet feeding cassette 50 that is detachable from the apparatus main body 100 includes a cassette pocket 3 that is a frame, a separation pad 6, an intermediate plate 2, and the like. . The sheet P before printing is stacked on the intermediate plate 2 pressed by the intermediate plate urging spring 4 so as to be rotatable in the direction of the paper feed roller 5. When the sheet feeding cassette 50 is inserted into the apparatus main body 100, the sheet P is pressed and urged by the sheet feeding roller 5 supported by the apparatus main body 100. The sheet feeding roller 5 is formed of friction rubber on the sheet P feeding portion side, and feeds the uppermost sheet of the stacked sheets P into the apparatus main body 100 by using the frictional force. When a plurality of sheets P are to be fed at a time, they are separated by the separation pad 6 and only the top sheet P is fed into the image forming apparatus. The image forming apparatus has a photosensitive drum 30 for forming a latent image by electrophotographic method by laser exposure. The latent image is developed by a developer , that is, toner by a developing unit, and the developed image is developed into a fixing roller pair 33. Is fixed by heating. Thereafter, the sheet P is discharged to a discharge tray 35 by a pair of discharge rollers 34 or the like.
[0004]
FIG. 10 is a cross-sectional view of a conventional cassette feeding apparatus.
[0005]
The sheet P before printing is stacked on the intermediate plate 2 pressed by the intermediate plate urging spring 4 so as to be rotatable in the direction of the paper feed roller 5. The sheet feeding cassette 50 is provided with side regulation guides 12 that can move in the width direction of the sheet P and position the sheet P in the width direction corresponding to the sheets P of different sizes. Further, the sheet feeding cassette 50 is provided with a trailing edge regulating guide 13 that can move in the longitudinal direction of the trailing edge of the sheet P and that positions the sheet P in the longitudinal direction. When the sheets P are stacked on the intermediate plate 2, the user needs to stack the sheets P while pushing down the intermediate plate 2 in the direction opposite to the pressing direction of the intermediate plate biasing spring 4, and the setting operability of the sheet P is somewhat troublesome. Met.
[0006]
In order to solve the above problem, there is a paper feed cassette 50 provided with an intermediate plate stopper mechanism. When the user pushes the middle plate 2 down to the lowest position once before the sheets P are stacked, the middle plate 2 comes into contact with the middle plate stopper 11 and is fixedly held at the lowest position (indicated by a solid line). Since the middle plate 2 is fixedly held at the lowermost position, the sheets P can be easily stacked on the middle plate 2.
[0007]
The sheet P can be pressed against the sheet feeding roller 5 by storing the sheet feeding cassette 50 loaded with the sheets P in the apparatus main body 100. In the case of the paper feed cassette 50 having the intermediate plate stopper mechanism, when the paper supply cassette 50 is stored in the apparatus main body 100, the intermediate plate stopper release guide 14 provided on the apparatus main body 100 and the intermediate plate stopper 11 come into contact with each other (indicated by broken lines). Then, the middle plate stopper 11 is rotated in the direction of the arrow to release the fixing of the middle plate 2, the middle plate 2 is raised and rotated (indicated by a broken line), and the sheet P is pressed by the paper feed roller 5. The Further, when the paper feed cassette 50 is stored in the apparatus main body 100, the apparatus main body 100 has a leaf spring (not shown) as a cassette holding means so that the paper feed cassette 50 is stably positioned at a regular position. Etc.
[0008]
[Problems to be solved by the invention]
However, the conventional example has the following problems. In the case of the paper feed cassette 50 that does not have an intermediate plate stopper mechanism, there is some trouble when setting the sheet P in the paper feed cassette 50 as described above.
[0009]
In the case of the paper feed cassette 50 having the middle plate stopper mechanism, the set operability of the sheet P is improved as compared with the paper feed cassette 50 having no middle plate stopper mechanism, but in order to fix the middle plate 2 at the lowest position. Needs to push the middle plate 2 down to the lowest position once before the sheets P are stacked. Further, when the middle plate stopper 11 is in a position where it can be easily operated by the user, when the user stacks the sheets P, the middle plate stopper 11 may be accidentally released, and the middle plate 2 may rise. It was.
[0010]
An object of the present invention is to provide a sheet feeding apparatus for enhancing a set operation of the paper cassette of the sheet.
[0011]
[Means for Solving the Problems]
A typical configuration of the sheet feeding apparatus according to the present invention includes a sheet feeding roller for feeding sheets, a sheet feeding cassette that is detachable from the feeding apparatus main body, and a pivotable arrangement on the sheet feeding cassette. In the sheet feeding apparatus, comprising: a sheet placing member for stacking sheets; and a biasing spring for biasing the sheet placing member in the direction of the sheet feeding roller. A pressure release spring for urging the member in a direction opposite to the direction of the paper feed roller by the bias spring, and removing the paper feed cassette from the main body of the feeding device to thereby release the sheet by the pressure release spring. The placement member is pressed and urged in the direction opposite to the direction of the paper feed roller, and the pressure release spring and the sheet placement member are separated by storing the paper feed cassette in the feeder main body. The biasing spring A sheet feeding apparatus which is characterized in that over preparative mounting member is urged to the feed roller direction.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
1 to 4 are block diagrams of a first embodiment of a cassette feeding apparatus according to the present invention.
[0013]
FIG. 1 is a cross-sectional view showing a state where the paper feed cassette 50 is removed from the apparatus main body 100. FIG. 2 is a perspective view showing a state in which the paper feed cassette 50 is removed from the apparatus main body 100. The intermediate plate 2 is rotatably attached around a rotation shaft 10 provided in the cassette pocket 3 and is pressed and urged by a middle plate urging spring 4 in a direction in which it is pressed against the paper feed roller 5.
[0014]
The middle plate pressure release spring 1, which is a torsion coil spring, is mounted coaxially with the middle plate rotation shaft 10 on the cassette pocket 3, and one side 1 b of the arm is in contact with a spring abutting portion 3 a provided on the cassette pocket 3. The other side 1a of the arm is movable in the slit portion 2a formed in the intermediate plate 2 and has a pressing urging force in the direction opposite to the pressing direction of the intermediate plate by the intermediate plate urging spring 4. When the paper feed cassette 50 is detached from the apparatus main body 100, the abutting portion 1a1 of the arm 1a is in contact with the end surface of the slit portion 2a of the intermediate plate 2, and the intermediate plate 2 is energized. The spring 4 is pressed and biased in the direction opposite to the pressing rotation direction. At this time, the rotational force of the intermediate plate 2 due to the pressing force of the intermediate plate pressure release spring 1 is larger than the rotational force of the intermediate plate 2 due to the pressing force of the intermediate plate biasing spring 4 in a state where the intermediate plate 2 is at the lowest position. Therefore, the middle plate 2 is held at the lowest position. That is, by removing the sheet feeding cassette 50 from the apparatus main body 100, the middle plate 2 is automatically held at the lowermost position, so that an operation of pushing down the middle plate 2 when the sheet P is set in the sheet feeding cassette 50 is unnecessary. Thus, the paper setting operability is improved.
[0015]
FIG. 3 is a cross-sectional view showing a state in which the paper feed cassette 50 is inserted into the apparatus main body 100. FIG. 4 is a cross-sectional view showing a part of the sheet feeding cassette 50 and the apparatus body 100 when the sheet feeding cassette 50 is inserted into the apparatus body 100.
[0016]
As shown in FIG. 4, the sheet feeding cassette 50 is inserted into the apparatus main body 100 by sliding in the arrow direction A, whereby the inclined surface portion 7 a of the intermediate plate pressure release guide 7 on the apparatus main body 100 and the intermediate plate pressure release spring 1. The arm 1a of the intermediate plate pressure release spring 1 once rotates in the arrow direction B and is pushed down to the one-dot chain line state. When the sheet cassette 50 is further slid, the arm 1a of the intermediate plate pressure release spring 1 rotates in the arrow direction C. When the insertion of the sheet cassette 50 into the apparatus main body 100 is completed, the intermediate plate pressure release spring 1 is completed. The arm 1a is in a broken line state, and is fixed in a state where the inclined surface portion 1a3 of the arm 1a of the intermediate plate pressure release spring 1 and the inclined surface portion 7b of the intermediate plate pressure release guide 7 indicated by the broken line are in contact with each other. At this time, the abutting portion 1a1 of the arm 1a of the intermediate plate pressure release spring 1 and the slit of the intermediate plate 2 from the fully loaded state of the sheets P on the intermediate plate 2 (indicated by a solid line) to the state where there is no sheet P (broken line state). The sheet P is separated from the end surface of the portion 2 a, and the pressing force by the intermediate plate pressure release spring 1 does not act on the intermediate plate 2, and the sheet P is pressed and urged by the intermediate plate urging spring 4 to the paper feed roller 5. .
[0017]
Further, as shown in FIG. 3, when the paper feed cassette 50 is completely inserted into the apparatus main body 100, the pressing force by the intermediate plate pressure release spring 1 presses and urges the intermediate plate pressure release guide 7 slope portion 7b. The paper feed cassette 50 is pressed in the direction opposite to the direction in which it is pulled out from the apparatus main body 100, and is stably positioned with respect to the apparatus main body 100.
[0018]
According to the above configuration, by removing the paper feed cassette 50 from the apparatus main body 100, the middle plate 2 is automatically held at the lowest position, so that the operability of setting the sheet P to the paper feed cassette 50 is improved. . Further, since the middle plate 2 is always held at the lowermost position by the biasing force of the spring, there is no fear that the middle plate 2 will rise due to an erroneous operation or the like during paper setting.
[0019]
Further, by using the intermediate plate pressure release spring 1 for holding the intermediate plate 2 in the lowest position, the sheet feeding cassette 50 is positioned with respect to the apparatus main body 100. There is no need to use parts, resulting in cost reduction.
[0020]
Further, in this embodiment, the rotational force of the intermediate plate 2 by the intermediate plate pressure release spring 1 is larger than the rotational force of the intermediate plate 2 by the intermediate plate biasing spring 4 in a state where the intermediate plate 2 is at the lowest position. Although the intermediate plate 2 is held at the lowest position, the rotational force of the intermediate plate 2 by the intermediate plate pressure release spring 1 is smaller than the rotational force of the intermediate plate 2 by the intermediate plate biasing spring 4, and the intermediate plate 2 is at the lowest position. Even if the sheet P is not held, the force to push the middle plate 2 downward can be small, so that the operability of setting the sheet P to the sheet feeding cassette 50 is improved.
[0021]
(Second embodiment)
5 to 8 are block diagrams of the first embodiment of the cassette feeding apparatus according to the present invention.
[0022]
FIG. 5 is a cross-sectional view showing a state where the paper feed cassette 50 is detached from the apparatus main body 100. FIG. 6 is a perspective view showing a state where the paper feed cassette 50 is detached from the apparatus main body 100.
[0023]
The intermediate plate 2 is rotatably attached around a rotation shaft 10 provided in the cassette pocket 3 and is pressed and urged by a middle plate urging spring 4 in a direction in which it is pressed against the paper feed roller 5.
[0024]
The intermediate plate pressure release arm 8 is mounted coaxially with the intermediate plate rotation shaft 10 on the cassette socket 3 and is reverse to the intermediate plate 2 pressing direction by the intermediate plate bias spring 4 by the intermediate plate pressure release arm biasing spring 9. It is pressed in the direction. The protrusion 8a formed on the intermediate plate pressure release arm 8 can move through the slit portion 2a formed on the intermediate plate 2. When the paper feed cassette 50 is removed from the apparatus main body 100, the protrusion 8a of the intermediate plate pressure release arm 8 contacts the end surface of the slit portion 2a of the intermediate plate 2, and the intermediate plate 2 is pressed by the intermediate plate biasing spring 4. Press and urge in the rotation direction and the reverse rotation direction. At this time, the rotational force of the intermediate plate 2 due to the pressing force of the intermediate plate pressure release arm urging spring 9 is the rotational force of the intermediate plate 2 due to the pressing force of the intermediate plate urging spring 4 in a state where the intermediate plate 2 is in the lowest position. Therefore, the middle plate 2 is held at the lowest position. That is, by removing the sheet feeding cassette 50 from the apparatus main body 100, the middle plate 2 is automatically held at the lowermost position, so that an operation of pushing down the middle plate 2 when the sheet P is set in the sheet feeding cassette 50 is unnecessary. Thus, the paper setting operability is improved.
[0025]
FIG. 7 is a cross-sectional view showing a state in which the paper feed cassette 50 is inserted into the apparatus main body 100. FIG. 8 is a cross-sectional view showing a part of the sheet feeding cassette 50 and the apparatus body 100 when the sheet feeding cassette 50 is inserted into the apparatus body 100.
[0026]
As shown in FIG. 8, the sheet cassette 50 is inserted into the apparatus main body 100 by sliding it in the arrow direction A, so that the inclined surface portion 7a of the intermediate plate pressure releasing guide 7 on the apparatus main body 100 and the intermediate plate pressure releasing arm 8 are inserted. The intermediate plate pressure release arm 8 once rotates in the arrow direction B and is pushed down to the one-dot chain line state. When the sheet feeding cassette 50 is further slid, the intermediate plate pressure releasing arm 8 rotates in the arrow direction C, and when the insertion of the sheet feeding cassette 50 into the apparatus main body 100 is completed, the intermediate plate pressure releasing arm 8 is in a broken line state. Thus, the inclined portion 8c of the intermediate plate pressure release arm 8 and the inclined portion 7b of the intermediate plate pressure release guide 7 indicated by the broken line are fixed in contact with each other. At this time, the end face of the protruding portion 8a of the intermediate plate pressure release arm 8 and the slit portion 2a of the intermediate plate 2 from the full loading state of the sheets P on the intermediate plate 2 (shown by a solid line) to the state where there is no sheet P (broken line state) The sheet P is not urged against the intermediate plate 2 by the intermediate plate pressure release spring 1, and the sheet P is urged against the sheet feeding roller 5 by the intermediate plate urging spring 4.
[0027]
As shown in FIG. 7, when the paper feed cassette 50 is completely inserted into the apparatus main body 100, the pressing force by the intermediate plate pressure release arm urging spring 9 presses and urges the intermediate plate pressure release guide 7 slope portion 7b. As a result, the paper feed cassette 50 is pressed in the direction opposite to the direction in which it is pulled out from the apparatus main body 100, and is stably positioned with respect to the apparatus main body 100.
[0028]
According to the above configuration, by removing the paper feed cassette 50 from the apparatus main body 100, the middle plate 2 is automatically held at the lowest position, so that the operability of setting the sheet P to the paper feed cassette 50 is improved. . Further, since the middle plate 2 is always held at the lowermost position by the biasing force of the spring, there is no fear that the middle plate 2 will rise due to an erroneous operation or the like during paper setting.
[0029]
Further, by using the intermediate plate pressure release arm 8 and the intermediate plate pressure release arm biasing spring 9 for holding the intermediate plate 2 in the lowest position, the paper cassette 50 is positioned with respect to the apparatus main body 100. There is no need to use a separate part such as a leaf spring which is a cassette holding means, and the cost is reduced.
[0030]
In this embodiment, the rotational force of the intermediate plate 2 by the intermediate plate pressure release arm biasing spring 9 is greater than the rotational force of the intermediate plate 2 by the intermediate plate biasing spring 4 in a state where the intermediate plate 2 is at the lowest position. The intermediate plate 2 is held at the lowest position, but the rotational force of the intermediate plate 2 by the intermediate plate pressure release arm biasing spring 9 is smaller than the rotational force of the intermediate plate 2 by the intermediate plate biasing spring 4, and the intermediate plate Even if 2 is not held at the lowermost position, the force for pushing down the intermediate plate 2 can be small, so that the operability of setting the sheet P to the paper feed cassette 50 is improved.
[0031]
【The invention's effect】
According to the present invention, when the sheet placing member is automatically held at the lowermost position by the pressure release spring by removing the sheet feeding cassette from the feeder main body , the sheet is placed on the sheet feeding cassette. It becomes possible to improve the property. Further, even if the sheet feeding cassette is biased in the direction opposite to the sheet feeding roller direction by the pressure release spring and is not held at the lowermost position, the force for pushing down the sheet placing member when setting the sheet can be reduced. Therefore, also in this case, it is possible to improve the operability of setting the sheet to the sheet feeding cassette.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a paper feed cassette according to a first embodiment of the present invention. FIG. 2 is a perspective view of a paper feed cassette according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view of a cassette feeding apparatus according to a first embodiment of the present invention. FIG. 5 is a cross-sectional view of a cassette feeding apparatus according to a second embodiment of the present invention. FIG. 6 is a perspective view of a sheet feeding cassette according to a second embodiment of the present invention. FIG. 7 is a sectional view of a cassette feeding apparatus according to the second embodiment of the present invention. FIG. 9 is a cross-sectional view of an entire image forming apparatus. FIG. 10 is a cross-sectional view of a cassette feeding apparatus according to a conventional example.
DESCRIPTION OF SYMBOLS 1 Middle plate pressure release spring 2 Middle plate 3 Cassette socket 4 Middle plate biasing spring 5 Paper feed roller 6 Separation pad 7 Middle plate pressure release guide 8 Middle plate pressure release arm 9 Middle plate pressure release arm biasing spring 50 Paper feed cassette 100 Device body P sheet

Claims (5)

A sheet feeding roller for feeding sheets, a sheet feeding cassette that is detachable from the feeding apparatus body , a sheet placing member that is rotatably disposed on the sheet feeding cassette and for stacking sheets; An urging spring for urging the sheet placing member in the direction of the sheet feeding roller;
A pressure release spring for urging the sheet placing member in a direction opposite to the direction of the sheet feeding roller by the urging spring;
By removing the paper feed cassette from the feeder main body, the sheet placing member is pressed and urged in the direction opposite to the paper feed roller direction by the pressure release spring, and the paper feed cassette is moved to the feeder main body. The pressure release spring and the sheet placing member are separated from each other, and the sheet placing member is urged in the direction of the sheet feeding roller by the urging spring. Feeding device. The pressure release spring that biases the sheet placing member in the direction opposite to the direction of the paper feed roller is a torsion coil spring, one side of an arm of the torsion coil spring is fixed to the paper feed cassette, and the other side is sheet feeding apparatus according to claim 1, characterized in that biasing the sheet placing member in contact sheet placing member and those in the paper feed row La direction opposite direction. Upon insertion of the paper feed cassette to the apparatus main body, a guide to press urging the other side and abuts on the sheet stacking cassette arms of the helical torsion coil spring in a direction opposite to the direction to be pulled out from the feeding apparatus body a sheet supply apparatus according to claim 2, characterized in that it has.   A pressure release arm rotatably supported by the paper feed cassette; and the pressure release arm biases the sheet placement member in a direction opposite to the paper feed roller direction by the pressure release spring. The sheet feeding apparatus according to claim 1, wherein the sheet feeding device is in contact with a placement member and presses and urges the sheet placement member in a direction opposite to the direction of the sheet feeding roller.   And a guide that presses and urges the sheet cassette in a direction opposite to a direction in which the sheet cassette is pulled out from the apparatus body when the sheet cassette is inserted into the apparatus body. The sheet feeding apparatus according to claim 4.

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