JP3955444B2 - Paper feeding device and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a paper feeding device additionally used in an image forming apparatus such as a copying machine, a printer, and a facsimile, and an image forming apparatus including the same.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine is provided with a sheet feeding device that supplies a sheet placed on a sheet tray to an image forming apparatus via a sheet feeding roller. The paper feeding device presses the paper placed on the paper tray against the paper feeding roller and sequentially supplies the paper to the image forming apparatus by the frictional force with the paper feeding roller.
For example, in a paper feeder disclosed in Japanese Patent Laid-Open No. 5-92833, a pressing spring is attached to a pressing member that presses a sheet, and an adjustment plate that adjusts the length of the pressing spring and a cam surface of the adjustment plate An adjusting member having a cam portion to be engaged is provided. Therefore, the adjustment member is slid by operating the knob portion, and the adjustment plate is rotated by the cam portion of the adjustment member to be moved, thereby extending the pressing spring in the pulling direction, for example, to the sheet by the pressing member. The pressing force is increased to adjust the pressing force on the paper.
[0003]
[Problems to be solved by the invention]
However, since the conventional sheet feeding device has a configuration in which the adjusting plate and the adjusting member are arranged in the sheet surface direction in addition to the pressing member, there is a problem that the device is increased in size accordingly. In addition, when assembling these components, there is a problem that the troublesome work of assembling a plurality of members against the urging force of the pressing spring is required, and the assembling workability is poor.
Accordingly, the present invention provides a sheet feeding device and an image forming apparatus that can reduce the size of the apparatus, have good assembling workability, and can adjust the pressing force corresponding to the sheet. is there.
[0004]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is configured to be attachable to an image forming apparatus, and the paper placed on a paper tray in a case (for example, the case 6 in the embodiment) is imaged via a paper feed roller. In the sheet feeding device that supplies the forming device, the case rotatably supports pivot shafts (for example, the pivot shaft 14 in the embodiment) provided on both sides of the paper tray, and biases the paper tray (for example, The sheet is pressed toward the sheet feeding roller via the coil spring 20) in the embodiment, and a torque is applied to the rotation shaft between the rotation axis of the sheet tray and the case to press the sheet tray toward the sheet feeding roller. A torsion spring is provided, and a switching mechanism capable of restricting the linkage of the torsion spring to the rotation shaft is provided between the torsion spring and the rotation shaft.
[0005]
With this configuration, the paper tray is pressed toward the paper feed roller only by the pressing force of the biasing mechanism, and the paper tray is pressed toward the paper feed roller by both the biasing mechanism and the torsion spring. The pressing force can be adjusted only by selecting the switching mechanism.
[0006]
The present invention is configured to be attachable to an image forming apparatus and supplies a sheet placed on a sheet tray in a case to the image forming apparatus via a sheet feeding roller. , The base plate 11 in the embodiment) and a tray body (for example, the tray body 12 in the embodiment) are connected to each other so as to be bendable. A rotation shaft is provided at both ends of the side of the paper tray on the base plate side. The side wall (for example, side wall 4 in the embodiment) is rotatably supported, while a part of the tray main body is movably supported by the case, and the tray main body is biased to the paper feed roller side via a biasing mechanism. An arm portion (for example, the arm portion 17 in the embodiment) extending in the rotation radius direction of the rotation shaft is provided on the rotation shaft, and the arm portion is engaged between the arm portion and the case. By providing a torsion spring that can press the tray body toward the paper feed roller, and a switching mechanism that can regulate the engagement of the torsion spring to the arm part is provided between the torsion spring and the arm part. Features.
[0007]
With this configuration, the switching mechanism restricts the engagement of the torsion spring to the arm portion and presses the paper tray toward the paper feed roller only by the pressing force of the urging mechanism, and the switching mechanism The restriction on the engagement with the arm portion is released, and it is possible to switch between the case where the paper tray is pressed toward the paper feed roller by both the urging mechanism and the torsion spring.
[0008]
An image forming apparatus according to the present invention is an image forming apparatus including the paper feeding device described above .
The size of the image forming apparatus can be reduced by the size of the paper feeding device.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
As shown in FIG. 4, a printer (image forming apparatus) 1 is detachably mounted with a paper feeding device 3 in an opening 2 on a manual paper supply side for supplying printing paper. Note that the image forming apparatus can be applied to a copying machine, a facsimile, and the like in addition to a printer.
[0010]
As shown in FIGS. 1 to 3, the sheet feeding device 3 includes a resin case 6 having a pair of side walls 4 and 4 and a bottom wall 5 facing the side of the sheet. The paper supply side (the rear side, which is the left side in FIG. 1) and the paper discharge side (the front side, which is the right side in FIG. 1) of the case 6 are open, and each side wall 4 extends across the width direction of the paper. A shaft 7 (shown in FIGS. 2 to 4) is supported between the shaft 7 and a paper feed roller 8 made of rubber or resin. A joint portion 9 is provided on the paper discharge side so as to be engaged with the opening 2 on the paper supply side of the printer 1. The paper feed roller 8 is a roller that is driven by receiving power from the printer 1 to feed paper. Further, an outer lid (not shown) is attached to the outside of the side wall 4 so that the internal components cannot be seen.
[0011]
The case 6 is provided with a paper tray 10 on which a plurality of sheets are stacked and placed. The paper tray 10 is disposed between the side walls 4 and is movably provided on the paper feed roller 8 side. Specifically, the paper tray 10 includes a plate-like base plate 11 and a tray main body 12, and the front side of the base plate 11 and the rear side of the tray main body 12 are rotatably supported by a connecting shaft 13. The paper tray 10 is configured to be bendable about the connecting shaft 13. The base plate 11 is a member for supporting the tray body 12 on which the paper is placed from the back side.
The tray body 12 is provided with a guide plate (not shown) that can be adjusted to the length in the width direction of the paper. Furthermore, the paper tray 10 is locked by a lock mechanism (not shown) at the retracted position (position shown in FIG. 3), and unlocked by pressing a lock release button (not shown).
[0012]
A metal shaft (rotating shaft) 14 formed in a rising crank shape at the center of the base plate 11 is attached to the rear side of the base plate 11. A rising portion 15 formed at the center of the shaft 14 is fixed to the inner wall of the base plate 11. Both end portions of the shaft 14 extend laterally from the side wall 4 and are rotatably supported by the support portion 16 of the side wall 4. Meanwhile, one end side of the shaft 14 is formed as an arm portion 17 that is bent along the surface direction of the base plate 11 and extends in the rotational radius direction of the shaft 14, and extends along the outer surface of one side wall 4. ing.
[0013]
Guide rollers (a part of the tray main body 12) 18 are rotatably provided at both ends of the front side of the tray main body 12. The guide roller 18 engages with guide grooves 19 and 19 formed on the side walls 4 and 4 of the case 6 so that the front side of the tray body 12 can be moved back and forth when the tray body 12 moves back and forth. I am guiding you. And between the said base plate 11 and the tray main body 12, as shown in FIG. 2, FIG. 4, the coil spring (1st biasing mechanism, biasing mechanism) which biases the tray main body 12 ahead with respect to the base plate 11 is shown. 2 (only one is shown in FIG. 2) are interposed, and the tray main body 12 is pressed toward the paper feed roller 8 by the coil spring 20. Note that only one coil spring 20 may be provided at the center in the width direction of the base plate 11 and the tray body 12.
[0014]
Between the arm portion 17 of the shaft 14 and the side wall 4 of the case 6, a torsion spring (second urging mechanism) that engages with the arm portion 17 and can press the tray body 12 toward the paper feed roller 8. ) 21 is provided. Specifically, the torsion spring 21 has a coil-shaped portion 22 wound around the shaft 14, one end locked to the locking portion 23 of the side wall 4 of the case 6 and a crank portion 24 formed at the other end. The part 24 is attached to the arm part 17 so as to be engageable. Accordingly, when the other end of the torsion spring 21 urges the arm portion 17 forward, a rotational force acts on the shaft 14, the base plate 11 presses the tray body 12 via the rising portion 15 of the shaft 14, and the coil spring 20. At the same time, the tray body 12 is pressed toward the paper feed roller 8 side.
[0015]
A pin 25 is provided on the side wall 4 of the case 6 in which the torsion spring 21 is disposed, and a switching member (switching mechanism) 26 that switches between applying and releasing the pressing force to the paper tray 10 is rotatably supported by the pin 25. Has been.
The turning end 27 of the switching member 26 has a turning locus at a position that interferes with the turning range of the torsion spring 21, and a guide portion 28 is formed on the side wall 4 along the turning locus. That is, the rotation locus of the rotation end 27 of the switching member 26, that is, the guide portion 28 is locked to the arm portion 17 before the torsion spring 21 is locked to the arm portion 17, and the torsion spring 21 is linked to the arm portion 17. The position is set from a position to be restricted (linkage restriction position) to a position (linkage allowable position) where the torsion spring 21 is allowed to be locked to the arm portion 17.
[0016]
An elastic portion 29 is formed on the switching member 26 on the substantially opposite side of the rotation end 27. The elastic portion 29 is adapted to overcome the two protrusions 30 formed on the side wall 4 of the case 6 and switch with a sense of moderation from the linkage restriction position to the linkage permission position. Since the rotation end 27 of the switching member 26 is urged clockwise by the torsion spring 21 at the linkage restriction position, it is locked at the rear end of the guide portion 28.
[0017]
As shown in FIG. 3, an operation pin 31 is provided on the back side of the switching member 26, and the operation pin 31 protrudes from an arcuate guide hole 32 formed inside the side wall 4 of the case 6. The guide hole 32 is formed in a range in which the operation pin 31 moves when the switching member 26 is rotated around the pin 25. Therefore, when the operation pin 31 is moved along the guide hole 32, the switching member 26 is rotated, and the rotation end 27 can restrict the linkage of the torsion spring 21 to the arm portion 17. Here, the operation pin 31 is operated in a state where it is exposed from the inside of the side wall 4 of the case 6 after the tray body 12 is moved backward and locked (to a locking device not shown).
[0018]
Next, the operation will be described.
First, the tray main body 12 of the paper tray 10 is moved rearward to be locked by the lock mechanism, and the paper is set on the tray main body 12. Next, when the lock release button (not shown) is pressed to release the lock, the paper tray 10 receives a pressing force from the coil spring 20 or the coil spring 20 and the torsion spring 21 to feed the paper on the tray main body 12 to the paper feed roller. Move forward to press 8.
Here, prior to setting the paper, the operation pin 31 of the switching member 26 is operated in accordance with the paper according to the paper to be used. Specifically, when the paper to be used is heavy (weighing 160 to 200 g / m 2), the operation pin 31 of the switching member 26 is switched to the A side in FIG. On the other hand, when the paper to be used is light (weighing is 60 to 100 g / m 2), the operation pin 31 of the switching member 26 is switched to the B side along the guide hole 32.
[0019]
For example, when the operation pin 31 is set to the A side, as shown in FIG. 1, the switching member 26 is in the position indicated by the chain line, and the rotating end 27 of the switching member 26 is retracted to the front end of the guide portion 28. The crank portion 24 of the torsion spring 21 becomes a linkage allowable position that allows the crank portion 24 to be locked to the arm portion 17. Therefore, when heavy paper is placed on the tray main body 12 in this state, the tray main body 12 is provided with the arm portion 17, the shaft 14, and the rising portion 15 linked to the torsion spring 21 together with the pressing force of the coil spring 20. Since the pressing force applied by the base plate 11 is added to the sheet feeding roller 8, a sufficient pressing force can be applied to the paper feed roller 8 even for heavy paper. Therefore, there is no paper feed failure caused by the paper feed roller 8.
[0020]
Conversely, when the operation pin 31 is set to the B side, the switching member 26 is in the position indicated by the solid line, as shown in FIG. 1, and the rotation end 27 of the switching member 26 advances to the rear end of the guide portion 28. Then, the crank portion 24 is locked to the crank portion 24 of the torsion spring 21, and the crank portion 24 becomes a linkage restriction position where the linkage with the arm portion 17 is restricted before being locked to the arm portion 17. Therefore, when a sheet is placed on the tray body 12 in this state, only the pressing force by the coil spring 20 acts on the tray body 12 and the pressing force by the torsion spring 21 does not act, so the pressing force is reduced. be able to. Therefore, even if the paper to be used is a light paper, since the pressing force is too large, it is possible to prevent so-called double feeding in which a plurality of papers are fed together.
[0021]
Then, as the paper placed on the tray main body 12 is supplied and decreased, the tray main body 12 gradually approaches the paper feed roller 8, but the tray main body 12 is guided by the guide roller 18 to the guide groove 19 on the side wall 4. Therefore, the feeding operation of the paper to the paper feed roller 8 is not adversely affected.
[0022]
Therefore, according to this embodiment, when the tray body 12 of the paper tray 10 is pressed against the paper feed roller 8 only by the pressing force of the coil spring 20, the paper tray 10 is pressed by both the coil spring 20 and the torsion spring 21. The case where the tray main body 12 is pressed toward the paper feed roller 8 can be selected by the switching operation of the switching member 26 by the operation pin 31, so that the pressing force of the coil spring 20 or the torsion spring 21 itself is adjusted. Therefore, the entire apparatus can be reduced in size. In particular, since the torsion spring 21 is used, the arrangement space can be reduced. Further, since the structure for adjusting the pressing force of each of the springs 20 and 21 is not necessary, the number of parts is reduced and the assembling work is simplified. That is, when assembling at the side wall 4, it is only necessary to attach the torsion spring 21 to the shaft 14 and the switching member 26 to the pin 25, so that the assembling work can be performed easily.
[0023]
Since the arm portion 17, the switching member 26, and the torsion spring 21 are disposed outside the side wall 4, there is no restriction on the arrangement portion of the tray main body 12 and the base plate 11 on which the paper is placed, and the apparatus The whole can be reduced in size. Accordingly, the printer 1 having such a sheet feeding device 3 can be similarly reduced in size, and thus has an advantage of reducing the occupied space.
The present invention is not limited to the above embodiment. For example, without providing the base plate 11, a rotation shaft is provided on the side of the tray main body 12, and this is supported rotatably on the upper portion of the side wall 4. The tray body 12 may be pressed against the paper feed roller 8 by the coil spring 20 and the torsion spring 21 may be linked to the rotation shaft, and the switching member 26 may be provided here. In addition, another biasing mechanism such as another coil spring or a torsion spring may be provided in the above-described embodiment, and the plurality of biasing mechanisms may be selectively switched by a switching member.
[0024]
【The invention's effect】
As described above, according to the invention described in claim 1, since the paper tray is pressed against the paper feed roller by the biasing mechanism selected by the switching mechanism, the pressing force of each biasing mechanism itself is adjusted. Therefore, there is an effect that the apparatus can be reduced in size and can be easily assembled.
[0025]
According to the second aspect of the present invention, the paper tray is pressed by both the first biasing mechanism and the second biasing mechanism when the paper tray is pressed toward the paper feed roller only by the pressing force of the first biasing mechanism. Since the pressing force can be adjusted simply by selecting the pressing mechanism to the paper feed roller side, the configuration for adjusting the pressing force of each urging mechanism is not required, and the device is downsized. As a result, the assembly work can be easily performed.
[0026]
According to the invention described in claim 3, when the paper tray is pressed toward the paper feed roller only by the pressing force of the biasing mechanism, and the paper tray is pressed toward the paper feed roller by both the biasing mechanism and the torsion spring. Since the pressing force can be adjusted simply by selecting the switching mechanism with the switching mechanism, the structure for adjusting the pressing force of the urging mechanism and torsion spring is not required, and the device can be reduced in size and easily assembled. There is an effect that can be performed. Moreover, since the torsion spring is used, the arrangement space can be reduced.
[0027]
According to the fourth aspect of the invention, the switching mechanism restricts the engagement of the torsion spring to the arm portion and presses the paper tray toward the paper feed roller only by the pressing force of the urging mechanism, and the switching mechanism Since the restriction of the engagement of the torsion spring with respect to the arm portion can be released and the paper tray can be pressed against the paper feed roller by both the urging mechanism and the torsion spring, the urging mechanism and the torsion can be switched. A configuration for adjusting the pressing force of the spring is not required, and there is an effect that the apparatus can be reduced in size and can be easily assembled. In addition, since the torsion spring is provided on the side wall of the case, the arrangement space can be reduced.
[0028]
According to the fifth aspect of the present invention, there is an effect that the entire image forming apparatus including the paper feeding device can be reduced in size by the size reduction.
[Brief description of the drawings]
FIG. 1 is a perspective view of an embodiment of the present invention.
FIG. 2 is a perspective view in which a case according to an embodiment of the present invention is omitted.
FIG. 3 is a perspective view of the embodiment of the present invention as viewed from above.
FIG. 4 is a partial perspective view of the image forming apparatus according to the embodiment of the present invention.
[Explanation of symbols]
1 Printer (image forming device)
4 Side wall 6 Case 8 Paper feed roller 10 Paper tray 11 Base plate 12 Tray body 14 Shaft (rotating shaft)
17 Arm 20 Coil spring (first urging mechanism, urging mechanism)
21 Torsion spring (second biasing mechanism)
26 switching member (switching mechanism)

Claims (3)

  In a paper feeding device configured to be attachable to an image forming apparatus and supplying paper placed on a paper tray in the case to the image forming apparatus via a paper feeding roller, the case is provided with a circuit provided on both sides of the paper tray. The paper shaft is pressed to the paper feed roller side via a biasing mechanism while the moving shaft is rotatably supported, and a torque is applied to the rotating shaft between the rotating shaft of the paper tray and the case to make the paper A sheet feeding device comprising a torsion spring that presses the tray toward the sheet feeding roller, and a switching mechanism capable of regulating the linkage of the torsion spring with the rotation shaft between the torsion spring and the rotation shaft. .   In a paper feeding device configured to be attachable to an image forming apparatus and supplying paper placed on a paper tray in a case to the image forming apparatus via a paper feeding roller, the paper tray is bent at a base plate and a tray main body. It is configured to be freely connected, and a rotating shaft is provided at both ends of the side of the paper tray on the base plate side, and this is supported rotatably on the side wall of the case, while a part of the tray body side is supported movably on the case Then, the tray body is pressed toward the sheet feeding roller via the urging mechanism, and an arm portion extending in the rotation radius direction of the rotation shaft is provided on the rotation shaft, and an arm is provided between the arm portion and the case. A torsion spring that allows the tray body to be pressed toward the paper feed roller by engaging with the arm is provided, and the engagement of the torsion spring with the arm is regulated between the torsion spring and the arm. Sheet feeding apparatus is characterized by providing a possible switching mechanism. An image forming apparatus comprising the paper feeding device according to claim 1 .

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