JP3620182B2 - Paper transport device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet conveying apparatus suitable for use as a mechanism for conveying a sheet to a predetermined position in an image forming apparatus such as an electronic copying machine or a laser printer.
[0002]
[Prior art]
In an image forming apparatus that creates recording paper using an electrophotographic method, such as an electronic copying machine or a laser printer, a paper storage device such as a paper supply tray is mounted on a paper supply unit, and the paper storage device supplies the recording paper. A means for feeding paper while feeding one by one by a paper device is used.
[0003]
FIG. 16 is a schematic configuration layout diagram showing an example of a conventionally known paper feeding device. In FIG. 16, the paper feeding device is configured such that paper 51 is stacked on a paper feed tray (not shown) having a vertical mechanism, such as a paper feed tray, and is rotated up and down around a fulcrum 52. A call roller 53 to be switched, a switching mechanism 54 for controlling the rotation of the call roller 53 in the vertical direction, a friction roller 55, and a feed roller that is rotated in the vertical direction around a fulcrum 56 and switched in position. 57, a switching mechanism 58 for controlling the vertical movement of the feed roller 57, a sensor 59, and the like.
When the paper 51 is fed, the calling roller 53 is placed on the paper 51 with a predetermined weight, and the feeding roller 57 and the friction roller 55 are brought into contact with each other with a predetermined pressure. Of the feeding roller 57 and the friction roller 55, the feeding roller 57 is a driving roller and rotates by itself, and the friction roller 55 is stopped or reversely rotated at a very low speed.
[0004]
When the calling roller 53 is rotated in the direction of the arrow 60 in FIG. 16 in this state, the sheets 51 are called one by one and fed between the feeding roller 57 and the friction roller 55. Then, the sheet 51 is further fed to the side where the sensor 59 is arranged while the feeding roller 57 and the friction roller 55 are rotated in the directions of arrows 61a and 61b, respectively. At this time, the friction roller 55 is stopped with respect to the feeding roller 57 or is rotating backward at a very low speed, so that the friction roller 55 is rubbed on the back surface of the paper 51 to which the friction roller 55 is fed and a plurality of sheets are fed out. To prevent.
In addition, when the paper feeding is started in this way and the leading end of the paper 51 is not detected within a predetermined time when the sensor 59 should detect the paper 51, the apparatus determines that the paper 51 has jammed and stops the operation. . On the other hand, when the leading edge of the paper 51 is detected by the sensor 59 within a predetermined time, it is determined that the paper is normally fed and the operation is continued.
[0005]
By the way, in the image forming apparatus, when a large number of sheets 51 are stacked and stored on a sheet feed table such as a sheet feed tray, the stacked sheets 51 are shown in FIG. 14 and FIG. As shown in the A section, the peripheral portion generally contains more water than the central portion of the paper 51. As the moisture content difference increases, the distortion of the paper 51 also increases, and the upper surface is not flat.
When the paper 51 whose top surface is not flat is sent out by the calling roller 53 in this way, the contact surface between the calling roller 53 and the paper 51 is reduced as shown in FIG. The contact surface between the paper 51 and the paper 51 is biased so that only one end portion of the paper 51 is brought into contact and transport, and a transport skew (bias transport) of the paper 51 occurs.
[0006]
Therefore, as a method for solving these problems, for example, a structure shown in FIGS. 17 and 18 is known. In this structure, as shown in FIG. 18, a long hole 63 is provided on the side surface of a support frame 62 that rotatably supports the calling roller 53, and a support shaft 64 on the apparatus main body side is connected to the long hole 63. As shown in FIG. 19, due to the attachment and play between the long hole 63 and the support shaft 64, the calling roller 53 can be moved in the vertical direction together with the support frame 62, and the vertical movement of the calling roller 53 causes the distortion of the paper 51. There is also a technique for increasing the area of the calling roller 53 that contacts the paper 51 so as to follow. This technique can also be seen in, for example, Japanese Patent Laid-Open No. 5-43065.
[0007]
[Problems to be solved by the invention]
However, in the above-described conventional technique in which the calling roller 53 is moved in the vertical direction, the pressing nip force necessary for conveyance applied from the calling roller 53 to the paper 51 is determined by the weight of the calling roller 53 and the support frame 62. Therefore, in order to obtain a nip force based on the type and usage environment of the adaptive paper, it is necessary to change the weight of the calling roller 53 and the support frame 62 each time, and the troublesomeness of adjusting the nip force, There arises a problem that the space is increased and the cost is increased.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a paper transport device that can arbitrarily set a nip force based on the type and usage environment of an adaptive paper and that can be handled with a simple mechanism. There is to do.
Further, other objects will be made clear in the contents described below.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is characterized by taking the following technical means. That is, a roller shaft, a roller member, a core member to which the roller member is fixed, a through-hole through which the roller shaft formed in the core member passes, and is attached to the core member so as to be integrally rotatable, A rotation force transmitting means for rotating the roller member via the core member, and the inner surface of the through hole is in contact with the roller shaft only at a position corresponding to the rotation force transmitting means. This is used as a swing fulcrum of the core member.
[0010]
According to this configuration, the oscillating fulcrum of the roller mechanism is provided on the inner surface of the through hole formed in the core member of the roller mechanism or on the roller shaft passing through the through hole, and the roller member can be oscillated freely by this oscillating fulcrum. , The roller member can be surely pressed onto the paper via the roller shaft to apply a nip force.
Also, unlike the nip due to its own weight, it can be used in places where paper is always subjected to load, such as the separation roller and transport roller, and in places where a pressing nip from the side or bottom is required, improving the transport force at these locations. Can be planned.
Furthermore, since the position of the rocking fulcrum of the core member along the rotation axis direction of the roller shaft and the contact position of the rotational force transmitting means with the core member are matched, the core member rotates to the portion with the smallest rocking motion. The force transmission means can be brought into contact, and the rotational force can be reliably transmitted.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. The embodiments described below are preferred specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless stated, the present invention is not limited to these forms.
[0012]
FIG. 1 to FIG. 3 show the main configuration of a roller mechanism according to the present invention applied to a calling roller mechanism for calling (pushing out) paper from a paper feed tray in an image forming apparatus. FIG. FIG. 3 is a side view thereof, and FIG. 1 is a side view showing a part thereof broken.
1 to 3, reference numeral 1 denotes a swinging member, and the swinging member 1 is supported at one end on a support shaft 2A and swingable in the vertical direction with the support shaft 2A as a fulcrum. Reference numeral 3 denotes a coil spring that always presses the swinging member 1 downward, and reference numeral 4 denotes a control mechanism for switching the swinging member 1 in the vertical direction against the bias of the coil spring 4. Reference numeral 5 denotes a roller. The roller 5 is composed of two rollers, 5A and 5B, which are separately arranged at the front and rear positions of the swing member 1, and one of the rollers 5A rotates around the support shaft 2A. The other roller 5B is rotatably attached to the swing member 1 via the pivot 2B. The rollers 5A and 5B have the same structure, except that the roller shafts (support shaft 2A or pivot 2B) attached thereto are different. Therefore, what is described in the following description without being specified also applies to the rollers 5A and 5B, and when it is not necessary to specify the rollers, the rollers 5A and 5B are simply referred to as the rollers 5, The support shaft 2A and the pivot 2B will be described as the roller shaft 2.
[0013]
Next, the structure of the roller 5 will be described. The roller 5 is divided into a cylindrical core member 12 having a through-hole 11 through which the roller shaft 2 passes in the center, and an outer periphery of the core member 12 on the left and right. And a gear 14 as a rotational force transmitting means attached to the core member 12 so as to be integrally rotatable between the pair of rollers 5 and 5. In addition, as shown in FIG. 2, a drive gear 16 communicating with a drive source is always meshed with each gear 14 of the rollers 5A and 5B.
[0014]
Further, the inner surface of the through hole 11 of the core member 12 is in contact with the roller shaft 2 provided at the center only at the inner surface corresponding to the portion to which the gear 4 is attached, and the gear 4 so that both ends do not contact the roller shaft 2. The inside of the core member 12 is in a state of having an angle θ and scraped off, leaving only the inner side surface portion 15 substantially corresponding to
[0015]
Therefore, in the roller mechanism configured as described above, when the swinging member 1 is moved downward and the roller 5 comes into contact with the paper 30 as shown in FIG. 4, the upper surface of the paper seems to be wavy. In this case, since both ends of the inner surface of the through hole 11 of the core member 12 are not in contact with the roller shaft 2, the inner surface portion 15 in contact with the inner surface portion 15 is swung as a swing fulcrum, and the roller 5 is rotated. The nip force can be applied in contact with the wave of the upper surface of the surface.
When the driving gear 16 is rotated by a driving force of a driving source (not shown), the rollers 5A and 5B are both rotated in the same direction via the gear 14, and the paper is fed in the transport direction.
Further, in this structure, since the gear 14 and the inner side surface portion 15 are provided at substantially corresponding positions, the swing of the core member 12 at the swing fulcrum is small. For this reason, the shift of the meshing between the gear 14 and the drive gear 16 can be suppressed, and it can be dealt with by a slight adjustment of the backlash. Therefore, it is necessary to provide a new mechanism by adopting the structure of the present invention. Nor.
[0016]
FIG. 5 is a side view showing a first modified example of the roller mechanism in the present invention, which is partially cut away. In FIG. 5, the same reference numerals as those in FIGS. 1 to 4 denote the same components as those in FIGS.
The structure of the first modification shown in FIG. 5 has a tapered shape, whereas the two end portions excluding the inner side surface portion 15 are tapered in the form shown in FIGS. Instead of this, the inner member 15 is left and the inner diameter of the core member 12 is enlarged and scraped off. Here, the inner surface of the inner side surface portion 15 is rounded and chamfered so as to be in line contact with the roller shaft 2 in the circumferential direction.
Therefore, even in the structure of the first modified example, when the swinging member is moved downward and the roller 5 comes into contact with the paper (not shown), the core of the paper is wavy, In the inner surface of the through-hole 11 of the member 12, both end portions sandwiching the inner side surface portion 15 have a structure in which the inner diameter is enlarged and do not contact the roller shaft 2, so that the inner surface portion 15 in contact with the inner shaft portion 15 swings as a swing fulcrum. Then, the roller 5 can be brought into contact with the wave of the upper surface of the sheet to apply a nip force.
[0017]
FIG. 6 is a side view showing a second modification of the roller mechanism in the present invention, which is partially broken away. In FIG. 6, the same reference numerals as those in FIGS. 1 to 4 denote the same components as those in FIGS.
In the structure of the second modified example shown in FIG. 6, the diameters of the through holes 11 of the core member 12 are all the same, and instead, a large diameter is formed on a part of the roller shaft 2 substantially corresponding to the gear 14. A portion 17 is provided, and the large diameter portion 17 is brought into contact with the inner surface of the core member 12 so that the roller 5 is disposed on the roller shaft 2. Here, the outer peripheral surface of the large-diameter portion 17 is rounded and chamfered so as to be in line contact with the inner surface of the core member 12 in the circumferential direction.
Therefore, even in the structure of the second modified example, when the swinging member is moved downward and the roller 5 comes into contact with the paper (not shown), the core of the paper is wavy. Since the large-diameter portion 17 is in contact with the inner surface of the core member 12 on the inner surface of the through hole 11 of the member 12, both end portions sandwiching the large-diameter portion 17 are not in contact with the core member 12. The large diameter portion 17 is swung as a rocking fulcrum, and the roller 5 can come into contact with the wave of the upper surface of the sheet to apply a nip force.
[0018]
By the way, in the structure of the roller mechanism described in the above embodiment and each modified example, when the roller 5 swings in the paper transport direction, the paper is transported in an oblique contact with the paper. For this reason, sheet conveyance skew (uneven conveyance) is likely to occur. Therefore, it is necessary to suppress the swing of the roller 5 only in the vertical direction.
FIG. 7 is a side view of a mechanism for suppressing the movement of the roller in the present invention, and a part thereof is broken away. In FIG. 7, the same reference numerals as those in FIGS. 1 to 6 denote the same components as those in FIGS.
In addition to the structure of the form shown in FIGS. 1 to 6, the structure of the mechanism that suppresses the movement of the roller is formed in the gap between the through hole 11 and the roller shaft 2 at the end of the core member 12. An elastic spacer 18 made of sponge or the like is interposed so that the spacer 18 functions as a damper. The roller 5 is restrained from swinging until the roller 5 comes into contact with the paper. In the case where a wave is generated, the core member 12 is allowed to swing up and down with the inner side surface portion 15 as a swing fulcrum by elastic deformation of the spacer 18, and the roller 5 is aligned with the wave on the upper surface of the sheet. So that nip force can be applied.
FIG. 8 is a top view of a modified example of the mechanism for suppressing the movement of the roller, and FIG. 9 is a side view thereof. As shown in FIGS. 8 and 9, at the end of the core member 12, the side surface of the core member 12 is sandwiched between a pair of guide plates 19A and 19B, and is only swung up and down by the guide of the pair of guide plates 19A and 19B. It is good to be able to move.
[0019]
FIG. 10 is a longitudinal side view showing a third modification of the roller mechanism of the present invention. In FIG. 10, the same reference numerals as those in FIGS. 1 to 6 denote the same components as those in FIGS.
The structure of the third modification is a structure in which three roller members 13, 13 </ b> A, 13 </ b> B, and 13 </ b> C are provided on the core member 12 at substantially equal intervals. Further, a gear 14 is attached between the roller member 13A and the roller member 13B, and an inner side surface portion 15 in contact with the roller shaft 2 is provided at a position corresponding to the gear 14.
Therefore, in the structure of the third modification, the swing fulcrum is provided on one end side (the roller member 13A side) off the center. Even in this case, even if the swinging fulcrum is biased toward one end, the gear 14 is provided at a position corresponding to the swinging fulcrum, so that a shift in meshing between the gear 14 and the drive gear 16 can be suppressed.
[0020]
FIG. 11 is a side view showing a fourth modification of the roller mechanism in the present invention. In FIG. 10, the same reference numerals as those in FIGS. 1 to 6 denote the same components as those in FIGS.
The structure of the fourth modified example is such that the position where the gear 14 is attached is removed from the swing fulcrum (inner side surface portion 15), and the gear 14 is connected to the end of the core member 12 via the coupling mechanism 20. It is attached outside. In this structure, it is possible to swing only the roller member 13 together with the core member 12 without swinging the gear 14. This structure is effective when gear driving at the center of the roller 5 is impossible.
[0021]
In the above embodiments and modifications, the case where the present invention is applied to the calling roller mechanism in the image forming apparatus has been described. However, the present invention is not limited to this. For example, as shown in FIG. In such a feeding device, a structure provided on the friction roller 24 side may be used. In addition, the present invention can be widely applied as a paper transport device having a similar structure.
[0022]
【The invention's effect】
As described above, according to the present invention, the oscillating fulcrum of the roller mechanism is provided on the inner surface of the through hole formed in the core member of the roller mechanism or the roller shaft that passes through the through hole, and the roller is supported by the oscillating fulcrum. By rotating the member in a swingable manner, the roller member can be surely pressed onto the sheet via the roller shaft to apply a nip force.
Also, unlike the nip due to its own weight, it can be used in places where paper is always subjected to load, such as the separation roller and transport roller, and in places where a pressing nip from the side or bottom is required, improving the transport force at these locations. Can be expected.
[Brief description of the drawings]
FIG. 1 is a side view showing a part of a structure of a main part of a roller mechanism according to the present invention.
FIG. 2 is a top view of a roller mechanism according to the present invention.
FIG. 3 is a side view of a roller mechanism according to the present invention.
FIG. 4 is an operation explanatory view of a roller mechanism according to the present invention.
FIG. 5 is a side view showing a partially broken structure of a first modification of the mechanism of the present invention.
FIG. 6 is a side view showing a partially broken structure of a second modification of the mechanism of the present invention.
FIG. 7 is a side view showing a partially broken structure of a mechanism for suppressing the movement of a roller in the mechanism of the present invention.
FIG. 8 is a top view of a modified example of a mechanism for suppressing the movement of a roller in the mechanism of the present invention.
FIG. 9 is a side view of a modified example of a mechanism for suppressing the movement of a roller in the mechanism of the present invention.
FIG. 10 is a longitudinal sectional side view showing the structure of a third modified example of the mechanism of the present invention.
FIG. 11 is a side view showing the structure of a fourth modified example of the mechanism of the present invention.
FIG. 12 is a front view showing the structure of another modification of the mechanism of the present invention.
FIG. 13 is a diagram illustrating a problem of stacked paper.
14 is a schematic cross-sectional view taken along the line AA of FIG.
FIG. 15 is a diagram illustrating a problem of a conventional device.
FIG. 16 is a schematic arrangement view of a conventional apparatus.
FIG. 17 is a schematic top view showing another example of a conventional device.
18 is a partially enlarged view seen along the line BB in FIG. 17;
FIG. 19 is a diagram illustrating the operation of a conventional device.
[Explanation of symbols]
2 Roller shaft 5, 5A, 5B Roller 11 Through hole 12 Core member 13, 13A, 13B, 13C Roller member 14 Gear (rotational force transmission means)
15 Inner side (oscillating fulcrum)
17 Large diameter part (oscillation fulcrum)
20 Coupling mechanism

Claims (4)

A roller shaft;
A roller member;
A core member to which the roller member is fixed;
A through hole through which the roller shaft formed in the core member passes ,
It is attached to the core member so as to be integrally rotatable , and comprises a rotational force transmitting means for rotating the roller member via the core member,
The inner surface of the through hole is in contact with the roller shaft only at a position corresponding to the rotational force transmitting means, and the contacted portion serves as a swing fulcrum of the core member. Paper transport device. 2. The sheet conveying device according to claim 1, wherein the through hole has a tapered shape that is distributed in an axial direction so as to provide a fulcrum that allows the core member to swing freely with respect to the roller shaft. The through hole is formed such that the inner diameter of a part of the through hole is in contact with the outer diameter of the roller shaft so as to provide a fulcrum in which the core member can swingably rotate with respect to the roller shaft. The paper conveying apparatus as described. 2. The paper transport according to claim 1, wherein the outer diameter of a part of the roller shaft is formed such that the core member is in contact with the inner diameter of the through hole so as to provide a fulcrum that can swingably rotate with respect to the roller shaft. apparatus.

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