JP4462774B2 - Paper cassette and paper feeding method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a paper feed cassette provided in an image forming apparatus., And paper feeding methodAbout.
[0002]
[Prior art]
An image forming apparatus used for a facsimile apparatus or the like is equipped with a sheet feeding cassette that stores recording sheets supplied to an image forming mechanism in a stacked manner.
[0003]
  As this paper feed cassette, the upper surface is opened and the downstream end in the paper feed directionInA cassette case in which separation claw is provided and the sheets are stacked and accommodated therein, a push-up plate on which the sheets stacked and accommodated in the cassette case are placed, and the push-up plate A push-up plate support means for pivotally supporting the upstream end portion in the paper feed direction of the push-up plate so that the downstream end portion in the paper feed direction swings in the vertical direction and approaches and separates from the separation claw, and a cassette case A rear end guide for pressing the upstream end in the paper feeding direction on the upstream side in the paper feeding direction, and a pusher provided in the cassette case. A compression coil spring, which is an upward force acting means for supporting an upward force by supporting the downstream end of the raising plate in the paper feeding direction from the lower side;,There are some.
[0004]
That is, in this paper feed cassette, when the recording paper is stacked on the push-up plate and accommodated in the cassette case and the compression coil spring pushes up the push-up plate, the uppermost layer of the recording paper is pressed by the separation claw. Prevent upward swing of the push-up plate. When the cassette case is inserted into the main body of the image forming apparatus, the uppermost layer of the recording paper comes into contact with the paper feed roller provided on the main body of the image forming apparatus, and when the supply roller rotates, the uppermost recording paper is removed from the separation claw and removed from the cassette case. It comes to pay out.
[0005]
[Problems to be solved by the invention]
Conventionally, in this paper feed cassette, a fulcrum shaft provided fixedly at a fixed position in the cassette case as a push-up plate support means, that is, a structure in which the push-up plate is pivotally supported with a fixed fulcrum as a fulcrum is employed.
[0006]
Recently, as the capacity of image forming apparatuses increases, it has been demanded to adopt a large-capacity paper feed cassette that can accommodate several hundred sheets of recording paper. By the way, when several hundred sheets of recording paper are placed on the push-up plate, the push-up plate swings most downward with the fulcrum shaft as a fulcrum, and the recording paper is provided on the image forming apparatus main body. When several sheets of recording paper are placed on the push-up plate, the push-up plate swings upward with the fulcrum shaft as a fulcrum and the recording paper contacts the paper feed roller. And it is paid out.
[0007]
However, if the fulcrum of the push-up plate is fixed at a fixed position, it swings around the fulcrum where the push-up plate is fixed. Therefore, when there are several hundred sheets of recording paper loaded on the push-up plate The minimum inclination angle (recording paper conveyance angle) of the lifting plate with respect to the horizontal plane and the inclination angle of the lifting plate with respect to the horizontal plane (recording paper conveyance angle) when there are several sheets of recording paper loaded on the lifting plate. A big difference occurs. As a result, a large difference occurs between the magnitude of the conveying force when the supply roller contacts the recording paper and feeds the recording paper when there are several hundred sheets and the magnitude of the conveying force when there are several sheets. There is unevenness in the transport state.
[0008]
Further, conventionally, in this paper feed cassette, the compression coil spring, which is the upward force acting means, applies the upward force by supporting the downstream end of the push-up plate in the paper feed direction at a fixed position from the lower side. The position where the upward force is applied by supporting the raising plate from the lower side, that is, the push-up position is fixed at the downstream end portion in the sheet feeding direction to ensure a certain position in the sheet feeding direction.
[0009]
  By the way, recently, the size of recording paper used for image formation has increased, and there has been an increased opportunity to store recording paper of different sizes in a cassette and place it on a push-up plate. The size of the recording paper to be placed on the push-up plateIsIf it changes, the center-of-gravity position of the entire push-up plate moves accordingly. On the other hand, if the push-up position with respect to the push-up plate is constant, the movement of the center of gravity of the whole push-up plate cannot be dealt with, and the balance of the feed direction of the push-up plate changes and the compression coil of the upward force acting means The load applied to the spring also changes. For this reason, the magnitude of the force by which the compression coil spring of the upward force acting means swings the push-up plate upward to bring the recording paper into contact with the paper feed roller changes, and unevenness in the conveyance state of the recording paper occurs. ing.
[0010]
  The present invention relates to the number and size of sheets placed on the push-up plate.RiverPaper feed cassette that can transport the paper in stable contact with the supply roller, And paper feeding methodThe purpose is to provide.
[0011]
[Means for Solving the Problems]
  The sheet cassette according to the present invention has a cassette case in which an upper surface portion is opened and a separation claw is provided at a downstream end portion in the sheet feeding direction so that sheets are stacked and accommodated therein. The push-up plate on which the sheets stacked and accommodated in the cassette case are placed, and the downstream end of the push-up direction in the paper feed direction swing along the vertical direction so as to approach and separate from the separation claw. A lifting plate supporting means for swingably supporting the upstream end of the lifting plate in the sheet feeding direction and supporting the upstream end of the lifting plate in the feeding direction so as to be movable in the vertical direction; In a direction that intersects the paper directionCan be moved along the paper feeding direction according to the size of the paper to be extended and placed on the push-up plateA rear end guide that presses the upstream end in the paper feeding direction of the sheet placed and placed on the push-up plate, and a first upward force action that applies an upward force to the downstream end of the push-up plate in the paper feeding direction According to the size of the paper to be placed on the push-up plate between the means, the first upward force acting means and the push-up plate support meansIntegrated with the rear end guideAlong the feed directionWhatMovableA movable body that can move integrally with the rear end guide, an upward force acting body that is provided on the movable body and that can swing in the vertical direction and applies an upward force to the push-up plate, and the upward force acting body. A spring for applying an upward force,And second upward force application means for applying an upward force to the push-up plate.
Further, according to the paper feeding method of the present invention, the paper is stacked in a state where the paper is stacked on the push-up plate disposed inside the cassette case, and is accommodated in the cassette case, and the downstream end of the push-up plate in the paper feed direction The upstream end of the push-up plate in the paper feed direction is supported so that the upstream end in the paper feed direction of the push-up plate can be moved in the vertical direction. The upstream end of the paper stacked in the paper feeding direction is supported by a rear end guide provided so as to be movable along the paper feeding direction according to the size of the paper placed on the push-up plate. The push-up plate so as to press the downstream end portion in the paper feeding direction of the sheets stacked on the plate against the paper feed roller disposed adjacent to the downstream end portion in the paper feeding direction on the upper surface portion of the cassette case. The downstream end of the sheet feeding direction is urged upward by the first upward force application means, and the rear end guide A movable body movable integrally with the rear end guide, wherein the movable body is movable integrally with the rear end guide along the paper feed direction between the first upward force acting means and the first upward force acting means. A second upward force acting means provided on the body and capable of swinging vertically and applying an upward force to the push-up plate; and a spring for applying an upward force to the upward force acting body. Thus, the push-up plate is urged upward to rotate the paper feed roller in the paper feed direction.
[0012]
  According to the configuration of the present invention, the combination of the fact that the push-up plate swings in the vertical direction and the position where the push-up plate is supported moves in the vertical direction results in the push-up when there are several hundred sheets of recording paper. The difference between the magnitude of the raising plate conveying angle and the magnitude of the conveying angle of the push-up plate in the case of several sheets can be kept small. In addition, a second upward force application means is provided, and the position where the upward force is applied according to the size of the paper placed on the push-up plate, that is, the push-up position is moved along the paper feeding direction, so that the paper size is increased.ToThe upward force is applied at a position corresponding to the movement of the center of gravity of the entire lifting plate in response to stabilize the balance in the feeding direction of the lifting plate and to make the load applied to the first upward force acting means constant. Can do.
[0014]
According to the configuration of the present invention, the operation of setting the trailing edge guide to the position corresponding to the paper size can be easily performed, and the second upward force acting means is set to the position corresponding to the paper size. The operation can be easily performed by interlocking with the operation of the rear end guide.
[0016]
According to the structure of this invention, a 2nd upward force action means can be provided with a suitable structure.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIGS.
[0018]
FIG. 1 is a cross-sectional view schematically showing a vertical conveyance type image forming apparatus loaded with a paper feed cassette of the present invention.
[0019]
In FIG. 1, reference numeral 1 denotes an image forming apparatus main body, 2 denotes an image reading unit that is provided on the upper stage of the image forming apparatus main body 1 and reads an image written on the original, and 3 denotes a lower stage of the image forming apparatus main body 1. The sheet feeding cassette loading section 5 for loading the sheet feeding cassette 4 of the present invention provided in the section is provided in the middle section of the image forming apparatus main body 1 and forms an image by conveying the recording paper P vertically upward. This is an image forming mechanism that employs a method. 6 is provided along the direction orthogonal to the sheet feeding direction above the downstream end of the sheet feeding direction of the sheet feeding cassette 4 loaded in the sheet feeding cassette loading unit 3 and stacked on the sheet feeding cassette 4 and accommodated. A paper feed roller for feeding out the recording paper P to be printed, 7 is a transport roller for transporting the recording paper P fed from the paper feed cassette 4 by the paper feed roller 6 to the image forming mechanism 5, and 8 is an image by the image forming mechanism 5. Is a discharge roller for discharging the recording paper P on which the recording medium is recorded to a paper discharge receiving portion 9 provided in the image forming apparatus main body 1.
[0020]
  The paper feed cassette 4 of the present invention will be described with reference to FIGS. FIG. 2 is a cross-sectional view showing the paper feeding cassette in a state where the push-up plate is swung downward, and FIG. 3 shows the push-up plate.UpFIG. 4 is a plan view showing the paper feed cassette. FIG.
[0021]
In this embodiment, the paper feed cassette 4 is moved horizontally in a direction orthogonal to the paper feed direction through an opening formed in the side surface of the paper feed cassette loading section 3 in the image forming apparatus main body 1 to feed paper. It is designed to be taken in and out of the cassette loading unit 3.
[0022]
In the figure, 11 is a cassette case, 12 is a push-up plate, 13 is a compression coil spring which is one form of the first upward force acting means, 14 is a rear end guide, 15 is a push-up plate support means, and 16 is a second plate. It is an upward force acting means.
[0023]
The cassette case 11 has a flat rectangular box shape with the upper surface opened, and has a length corresponding to the length dimension and the width dimension of the maximum size recording sheet P in order to stack and accommodate the recording sheets P of a plurality of sizes. Dimensions and width dimensions are set. The cassette case 11 is set so that its length direction is along the sheet feeding direction. In FIGS. 2 to 4, the right end of the cassette case 11 is the downstream end wall in the sheet feeding direction and the left end wall is the sheet feeding. It is respectively set to the direction upstream side end wall part.
[0024]
A pair of width guides 21 are provided on the downstream side in the sheet feeding direction of the cassette case 11 so as to be located inside both side wall portions, and the width guides 21 approach each other along the width direction of the cassette case 11. It can be moved in the direction of separation, and the distance between the two is adjusted according to the width dimension of the recording paper P accommodated in the cassette case 11 to press the side edges on both sides of the recording paper P. The two side walls of the cassette case 11 on the upstream side in the paper feeding direction have, for example, two distances in the length direction based on the downstream end wall in the paper feeding direction according to the length dimension of the two types of recording paper P. The fulcrum shaft support portions 22A and 22B are formed at the positions where These fulcrum shaft support portions 22A and 22B are opened to form a recess, and have an axis line in a direction perpendicular to the paper feeding direction. A fulcrum shaft 28 of the rear end guide 14 described later is provided from above. It is detachably engaged and supported to be swingable.
[0025]
Further, a horizontal separation claw 23 is provided on the end wall of the cassette case 11 on the downstream side in the paper feeding direction toward the inside of the cassette case 11.
[0026]
The push-up plate 12 is used to place the recording paper P placed inside the cassette case 11 and stacked and accommodated. The push-up plate 12 is placed inside the cassette case 11 and is used to place recording paper P of several sizes. It has a rectangular shape corresponding to the maximum size recording paper P. On both sides of the push-up plate 12, a portion that overlaps a pair of sheet width guides 21 and a side piece 27 at the end of a rear end guide 14 to be described later is cut away to avoid this.
[0027]
  The push-up plate support means 15 is provided on the upstream side in the paper feed direction of the push-up plate 12 so that the downstream end of the push-up plate 12 in the paper feed direction swings along the vertical direction and approaches and separates from the separation claw 23. A push-up plate having a fulcrum shaft 26 that pivotally supports the end portion and supported by the fulcrum shaft 2612Is supported to move along the vertical direction.
[0028]
  Here, the configuration described below is provided. Standing pieces 24 are formed on the side wall portions on both sides at the upstream end in the sheet feeding direction of the push-up plate 12 so as to stand at right angles, and these standing pieces 24 are elongated holes extending in a predetermined length along the vertical direction. 25 is formed. In the long holes 25 formed in each of the upright pieces 24, fulcrum shafts 26 are provided on the inner surfaces of the side walls on both sides of the cassette case 11 along the direction perpendicular to the sheet feeding direction.Up and downIt is inserted and supported so as to be movable along the direction. As a result, the push-up plate 12 swings in the vertical direction so that the downstream end portion in the paper feeding direction approaches and separates from the separation claw 23 with the fulcrum shaft 26 at the upstream end portion in the paper feeding direction as a fulcrum. Is supported. Further, the long hole 25 moves along the vertical direction with the fulcrum shaft 26 as a guide, and accordingly, the entire push-up plate 12 moves along the vertical direction via the standing piece 24. As a result, the push-up plate 12 is supported so that the portion supported by the fulcrum shaft 26 can move in the vertical direction. The push-up plate support means may be formed with a long hole in the side wall portion of the cassette case 11 along the vertical direction, and the push-up plate 12 may be provided with a fulcrum shaft.
[0029]
The compression coil spring 13 is disposed between the bottom surface of the cassette case 11 and the push-up plate 12 at the downstream end in the sheet feeding direction inside the cassette case 11. As a result, the push-up plate 12 is supported at its downstream end in the paper feeding direction by the compression coil spring 13 from the lower side, and an upward elastic force is applied. The first upward force acting means is not limited to the compression coil spring 13, and may be configured using an elastic member that applies upward force to the push-up plate 12 from the lower side, the side, or the upper side.
[0030]
The rear end guide 14 is horizontally disposed in the cassette case 11 along a direction orthogonal to the paper feeding direction, and has a length corresponding to the width dimension of the cassette case 11 (larger than the push-up plate 12). A rectangular shape having a width shorter than the height of the wall of the cassette case 11 is formed. Both end portions of the rear end guide 14 are bent downward at a right angle to form side pieces 27, respectively, and these side pieces 27 are located in notches on both sides of the push-up plate 12. A fulcrum shaft 28 that protrudes outward along a horizontal direction orthogonal to the sheet feeding direction is provided at the upper ends of these side pieces 27, and this fulcrum shaft 28 is a fulcrum shaft support portion of the cassette case 11. These are selectively fitted to 22A and 22B from the upper side and supported so as to be swingable. In other words, the fulcrum shaft 28 pivotally supports the upper end of the rear end guide 14 so as to be swingable about an axis along a direction perpendicular to the sheet feeding direction.
[0031]
The rear end guide 14 is set at a position corresponding to the size of the recording paper P placed on the push-up plate 12, that is, the length in the paper feeding direction. For example, when the length of the recording paper P corresponds to the position 22B of the fulcrum shaft support portions 22A and 22B of the cassette case 11, the fulcrum shaft 26 is engaged and supported by the fulcrum shaft support portion 22B of the cassette case 11. . As a result, the rear end guide 14 is in a suspended state with the upper end supported by the fulcrum shaft 28.
[0032]
The second upward force acting means 16 is mounted on the push-up plate 12 between the compression coil spring 13 as the first upward force acting means and the fulcrum shaft 26 of the push-up plate support means 15 inside the cassette case 11. It is provided so as to be movable in the paper feeding direction according to the size of the recording paper P to be placed, and supports the push-up plate 12 to apply an upward force. In this embodiment, two portions are provided in the cassette case 11 at positions spaced apart in the width direction of the push-up plate below the upstream end of the push-up plate 12 in the sheet feeding direction.
[0033]
Here, the second upward force applying means 16 is movably disposed on the inner surface of the bottom wall of the cassette case 11 and is moved integrally in the side piece 27 of the rear end guide 14 or fixed in the feed direction. The movable body 31 and the downstream end of the sheet feeding direction disposed on the movable body 31 are supported so as to be swingable in the vertical direction about a pivot 33 perpendicular to the sheet feeding direction. It is pivoted by an upward force acting body 32 in contact, a torsion spring 34 provided on the pivot 33 for applying an upward force to the upward force acting body 32, and a pin 37 having a long hole 36 and one end provided on the lower surface of the upward force acting body 32. A long hole 36 is provided with a link 35 pivotally supported by a pin 38 provided in the movable body 31. The moving body 31 moves in the paper feeding direction in conjunction with the operation of setting the rear end guide 14 at a position corresponding to the size of the recording paper P placed on the push-up plate 12, that is, the length in the paper feeding direction, The recording paper P is set at the same position as the trailing edge guide 14. The upward force acting body 32 always applies an upward force to the push-up plate 12 by the torsion spring 34, and is swung in the vertical direction in response to the rocking of the push-up plate 12 in the vertical direction.
[0034]
The paper feed cassette 4 configured as described above will be described.
When the paper feed cassette 4 is used, the rear end guide 14 is moved along the paper feed direction according to the size of the recording paper P placed on the push-up plate 12, and the fulcrum shaft support portion 22A of the cassette case 11 is moved. 22B is selected and the fulcrum shaft 26 of the rear end guide 14 is engaged and supported, and the rear end guide 14 is set at a position corresponding to the size of the recording paper P. When the operation of setting the position of the rear end guide 14 is performed, the moving body 31 of each second upward force applying means 16 moves along the sheet feeding direction on the bottom wall portion of the cassette case 11 together with the rear end guide 14. Thus, the rear end guide 14 is set at the position where it is set. The position of the second upward force acting means 16 is appropriate for applying an upward force in order to keep the weight of the entire lifting plate 12 in accordance with the position of the center of gravity of the lifting plate 12 defined by the size of the recording paper P. The correct position is selected.
[0035]
First, the cassette case 11 is taken out from the sheet feeding cassette loading section 3 of the image forming apparatus main body 1 through the opening, and the push-up plate 12 is manually moved downward against the spring force of the compression coil spring 13 as shown in FIG. Push to swing downward about a fulcrum shaft 26 to a horizontal position. The recording paper P is housed from the upper side of the cassette case 11 and stacked on the push-up plate 12. The recording paper P is aligned with its upstream end (rear end) in the paper feed direction in contact with the front surface of the rear end guide 14 to determine the position in the paper feed direction.
[0036]
When the hand is released, the push-up plate 12 is pushed up by the compression coil spring 13 and swings upward about the fulcrum shaft 26, and the feeding direction in the uppermost layer of the recording paper P stacked on the push-up plate 12. The downstream end (front end) corresponds to the separation claw 23 of the cassette case 11. As a result, the recording paper P is pressed from the upper side and the upward swing of the lifting plate 12 is prevented. When the maximum number (several hundreds) of recording sheets P are stacked on the push-up plate 12, the state shown in FIG. In this case, the push-up plate 12 swings downward with the fulcrum shaft 26 as a fulcrum and is in a substantially horizontal state. The long hole 25 of the push-up plate 12 moves to the lower side and the upper end thereof is at a position reaching the position of the fulcrum shaft 26. Further, the upward force acting body 32 of the second upward force acting means 16 is pushed by the push-up plate 12 that swings downward and swings downward against the spring force of the torsion spring 34 to move with the moving body 31. It is in the position where it overlaps and becomes horizontal.
[0037]
In this state, the cassette case 11 is inserted into the paper feed cassette loading unit 3 of the image forming apparatus main body 1 through the opening. The uppermost layer of the recording paper P placed on the push-up plate 12 comes into pressure contact with the paper feed roller 6 provided in the paper feed cassette loading unit 3.
[0038]
When the paper feed roller 6 provided in the image forming apparatus main body 11 is rotated in the paper feed direction, the paper feed roller 6 is brought into frictional contact with the uppermost recording paper P and applies a conveying force toward the downstream side in the paper feed direction. As a result, the uppermost recording paper P is removed from the separation claw 23 and conveyed from the cassette case 11 to the downstream side in the paper feeding direction. When the recording paper P is sequentially fed and the number of recording papers P placed on the push-up plate 12 is sequentially reduced, the push-up plate 12 is pushed up by the compression coil spring 13 in accordance with the decrease. And swings upward about the fulcrum shaft 26. When the recording paper P placed on the push-up plate 12 runs out, the downstream end of the push-up plate 12 in the paper feeding direction is caught by the separation claw 23 as shown in FIG.
[0039]
Here, the first upward force acting means comprising the compression coil spring 13 presses the main driving force that pushes the push-up plate 12 upward and the recording paper P placed on the push-up plate 12 against the paper feed roller. To bear a certain pressing force.
[0040]
Further, as the number of stacked recording sheets P decreases and swings upward, the long hole 25 of the side piece 24 is supported by the fulcrum shaft 26 fixed to the cassette case 11 and moves upward. As a result, the entire push-up plate 12 moves upward. That is, the location of the push-up plate 12 supported by the fulcrum shaft 26 moves. When the recording paper P placed on the push-up plate 12 disappears, the lower end of the long hole 25 comes into contact with the support shaft 26 and the upward movement is stopped, whereby the upward movement of the entire push-up plate 12 is stopped. Stop. As described above, when the push-up plate 12 swings upward, the entire push-up plate 12 moves, so that the inclination angle (conveying angle) with respect to the horizontal plane at each position where the push-up plate 12 swings upward is conventionally increased. In this way, the push-up plate 12 becomes gentle as compared with the case where the push-up plate 12 does not move upward. That is, the difference between the horizontal state where the push-up plate 12 is located on the lowermost side and the conveyance angle when the push-up plate 12 is swung to the uppermost side is reduced.
[0041]
In this case, due to the combination of vertical swing and vertical movement of the push-up plate 12, the conveyance angle of the push-up plate 12 in the case where the number of the recording paper P is several hundred sheets is several sheets. The difference between the conveyance angle of the push-up plate 12 and the conveyance force of the press-up plate 12 can be kept small, and when the recording paper P is several hundred sheets, the supply roller contacts the recording paper P and feeds the recording paper P. It is possible to suppress the difference between the size and the conveyance force when there are several sheets of recording paper P, and to suppress the occurrence of unevenness in the recording sheet conveyance state between the two.
[0042]
Further, as the number of stacked recording sheets P decreases and swings upward, the upward force acting body 32 in the second upward force acting means 16 receives upward force from the torsion spring 34 and pushes up. While abutting against the lower surface of the plate 12, it swings upward about the pivot 33. As a result, the upward force acting body 32 applies an upward force to the push-up plate 12 from below. Then, when the recording paper P placed on the push-up plate 12 disappears and the push-up plate 12 swings to the maximum upper side and moves upward, the upward force acting body 32 also swings upward to the maximum. Thus, the upward force acting body 32 swings upward at an appropriate position in order to maintain the weight balance of the entire lifting plate 12 according to the position of the center of gravity of the lifting plate 12 defined by the size of the recording paper P. An upward force is always applied to the push-up plate 12 from below. Therefore, an upward force is applied to the push-up plate 12 at a position corresponding to the position of the center of gravity of the push-up plate 12 defined by the size of the recording paper P by the upward force acting body 32, and the weight balance of the push-up plate 12 as a whole. Can keep. The upward force applied by the second upward force acting means 16 to the push-up plate 12 is for weight balance.
[0043]
In this way, the second upward force application means 16 is provided, and the position where the upward force is applied according to the size of the recording paper P placed on the push-up plate 12, that is, the push-up position is moved along the paper feeding direction. Then, an upward force is applied in response to the movement of the center of gravity of the entire push-up plate 12 according to the size of the recording paper P, and the balance of the paper feed direction of the push-up plate 12 is stabilized and the first The load applied to the compression coil spring 13 of the upward force acting means can be made constant.
[0044]
Accordingly, the swing fulcrum moves upward as the recording sheet P loaded on the push-up plate 12 swings upward, and the second upward force acting means 16 causes the push-up plate 12 to move. By maintaining the weight balance, the recording paper can be brought into contact with the paper feed roller stably and conveyed regardless of the number and size of the recording paper placed on the push-up plate.
[0045]
The rear end guide 14 is arranged so as to be movable along the paper feeding direction in accordance with the size of the recording paper P placed on the push-up plate 12, and the rear end guide 14 and the second upward force acting means 16 are Since it can be moved integrally in the paper feeding direction, the operation of setting the trailing edge guide 14 to a position corresponding to the size of the recording paper P can be easily performed, and the second upward force acting means 16 can be used as the recording paper. The operation of setting the position according to the size of P can be easily performed by interlocking with the operation of the rear end guide 14.
[0046]
Further, the second upward force acting means 16 can include the upward force acting body 32 and the torsion spring 34 to provide the second upward force acting means 16 with an appropriate configuration.
[0047]
In addition, this invention is not limited to embodiment mentioned above, It can implement by changing variously. For example, the paper handled by the paper feed cassette is not limited to the recording paper, and for example, a document can be handled.
[0048]
【The invention's effect】
According to the paper feed cassette of the first aspect of the present invention, a combination of the fact that the push-up plate swings in the vertical direction and the position where the push-up plate is supported moves in the vertical direction results in a number of recording papers. The difference between the conveying angle of the lifting plate in the case of 100 sheets and the conveying angle of the lifting plate in the case of several sheets can be kept small, and the supply roller contacts the recording sheet and the recording sheet It is possible to prevent a large difference between the magnitude of the conveying force for feeding the sheet and the magnitude of the conveying force when there are several sheets, and to prevent the recording paper from being unevenly conveyed.
[0049]
In addition, a second upward force application means is provided, and the position where the upward force is applied according to the size of the paper placed on the push-up plate, that is, the push-up position is moved along the paper feeding direction, so that the paper size is increased. In response to the movement of the center of gravity of the entire push-up plate according to the size of the push-up plate, an upward force is applied to stabilize the balance in the paper feed direction of the push-up plate, and the load applied to the compression coil spring of the upward force acting means Can be constant.
[0050]
Therefore, regardless of the number and size of the recording papers placed on the push-up plate, the recording papers can be conveyed in contact with the supply roller stably and uniformly.
[0051]
According to the invention of claim 2, the operation of setting the trailing edge guide to a position corresponding to the paper size can be easily performed, and the second upward force acting means is set to a position corresponding to the paper size. This operation can be easily performed in conjunction with the operation of the rear end guide.
[0052]
According to invention of Claim 3, a 2nd upward force action means can be provided with a suitable structure.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing an image forming apparatus loaded with a paper feed cassette according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a paper feed cassette in the embodiment.
FIG. 3 is a cross-sectional view showing a paper feed cassette according to the embodiment.
FIG. 4 is a plan view showing a paper feed cassette according to the embodiment.
[Explanation of symbols]
1 ... image forming apparatus main body,
3 ... Paper cassette loading section,
4 ... Paper cassette,
11 ... cassette case,
12 ... Push-up plate,
13: Compression coil spring (first upward force acting means),
14 ... rear end guide,
15 ... Push-up plate support means
16 ... second upward force acting means,
22A, 22B ... fulcrum shaft support,
26 ... fulcrum shaft,
28 ... fulcrum shaft,
31 ... a moving body,
32 ... upward force acting body,
33 ... Axis,
34 ... Torsion coil spring,
P: Document (paper).

Claims (2)

A cassette case in which the upper surface is opened and a separation claw is provided at the downstream end in the paper feeding direction, and the paper is stacked and accommodated therein
A push-up plate on which a sheet placed inside the cassette case and stacked and accommodated in the cassette case is placed;
The upstream end of the push-up plate in the paper feed direction is swingably supported so that the downstream end of the push-up plate in the paper feed direction swings along the vertical direction and approaches and separates from the separation claw. And a lifting plate support means for supporting the upstream end of the lifting plate in the paper feeding direction so as to be movable in the vertical direction;
Feeding of the paper placed on the push-up plate, which is arranged so as to be movable along the paper feed direction according to the size of the paper placed on the push-up plate extending in a direction intersecting the paper feed direction. A rear end guide for holding the upstream end in the paper direction;
First upward force application means for applying an upward force to the downstream end of the push-up plate in the paper feeding direction;
Movable What the first line with the paper feed direction to the rear end guide integrally in accordance with the size of paper to be placed on the lifting plate with the upward force acting means and said lifting plate supporting means A movable body that can move integrally with the rear end guide, an upward force acting body that can swing in the vertical direction and applies an upward force to the push-up plate, and the upward force A spring for applying an upward force to the operating body, and a second upward force applying means for applying an upward force to the push-up plate;
A paper feed cassette comprising: Housed in the cassette case in a state where paper is stacked on a push-up plate arranged inside the cassette case,
The upstream end of the push-up plate in the paper feed direction can be swung in the vertical direction, and the upstream end of the push-up plate in the paper feed direction can be moved in the vertical direction. Support the side edges,
A trailing edge guide provided so that the upstream end of the paper stacked on the push-up plate can be moved along the paper feed direction according to the size of the paper placed on the push-up plate. Support,
The paper feed direction downstream end of the paper stacked on the push-up plate is pressed against a paper feed roller disposed adjacent to the paper feed direction downstream end on the upper surface of the cassette case. Urging the downstream end of the push-up plate in the paper feeding direction upward by the first upward force application means;
A movable body that is movable between the rear end guide and the first upward force acting means so as to be movable along the paper feed direction integrally with the rear end guide; A second upward force action member provided on the movable body and capable of swinging in the vertical direction and applying an upward force to the push-up plate; and a spring for applying an upward force to the upward force effector. Urging the push-up plate upward by a force application means;
A paper feeding method, wherein the paper feeding roller is rotated in the paper feeding direction.

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