JP2017095243A - Sheet feeder, image formation device, and image reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeder which prevents abnormal noise caused by resonance of a frame member which results from stick slip between a sheet fed by a feeding member during sheet feeding and a separation pad, and to provide an image formation device and an image reading device.SOLUTION: A sheet feeder includes: a feeding member which is rotationally driven so as to feed sheets; a sheet separation member which is disposed so as to be pressed against the feeding member; and a shaft support part which rotatably supports a shaft of the feeding member. A vibration inhibition member which inhibits vibration of a frame member is provided at the frame member provided with the shaft support part.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a sheet feeding apparatus, an image forming apparatus, and an image reading apparatus.

  Conventionally, it is a separation pad type sheet feeding device that feeds sheets one by one from a stacked sheet bundle, and generates abnormal noise due to stick slip, which is an intermittent slip between the sheet and the separation pad during sheet feeding. What has the structure which prevents is known. The separation pad method is a method of separating and feeding sheets one by one by a feeding roller that is rotationally driven so as to feed the sheet and a separation pad arranged so as to be pressed against the feeding roller.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses a sheet feeding device of such a separation pad type, in which a vibration suppressing member is provided on the side surface of the paper feeding roller as follows. In this sheet feeding apparatus, a sheet feeding roller that is in contact with the separation pad is provided coaxially with the axis of the sheet feeding roller so as to position the sheet feeding roller with respect to the separation pad. A vibration suppressing member that suppresses the vibration of the roller is provided. According to this sheet feeding device, the vibration of the sheet feeding roller is suppressed by changing the resonance point of the vibration of the sheet feeding roller by the vibration suppressing member. Since the sheet feeding roller whose vibration is suppressed in this way comes into contact with the sheet, it is possible to suppress the vibration of the sheet feeding roller caused by the stick slip and the vibration of the sheet feeding roller due to the vibration transmitted from the sheet. It is said that it is possible to suppress the generation of abnormal noise.

  However, when the inventors conducted an experiment on the separation pad type sheet feeding device, it was found that there were the following problems. That is, the vibration of the sheet generated by stick-slip between the sheet and the separation pad propagates to the frame member provided with the shaft support portion via the feeding roller and its shaft support portion, and the frame member resonates, and the abnormal noise is generated. It was found that there is a risk of occurrence.

  In order to solve the above-described problems, the present invention provides a feeding member that is rotationally driven so as to feed a sheet, a sheet separating member that is arranged to be pressed against the feeding member, and the feeding A shaft feeding unit that rotatably holds a rotation shaft of the member, and a vibration suppressing member that suppresses vibration of the frame member is provided on the frame member provided with the shaft supporting unit. It is characterized by that.

  According to the present invention, it is possible to prevent abnormal noise caused by resonance of the frame member due to stick slip between the sheet fed by the feeding member and the separation pad during sheet feeding.

1 is an external perspective view showing an example of the overall configuration of a laser printer according to an embodiment of the present invention. FIG. 2 is a schematic sectional view of the laser printer. The perspective view of a paper feed tray. The side view of a paper feeder. FIG. 3 is a perspective view of a paper feed stay that supports a paper feed roller and a damping material according to the first exemplary embodiment. FIG. 6 is a top view of the paper feed stay of FIG. 5 as viewed from above. FIG. 7 is a cross-sectional view taken along line AA of the paper feed stay in FIG. 6. FIG. 2 is a schematic cross-sectional view of a laser printer showing a state in which an upper cover and a transfer cover are closed. FIG. 2 is a schematic cross-sectional view of a laser printer showing a state where an upper cover and a transfer cover are opened. FIG. 10 is a schematic cross-sectional view of the laser printer showing a state in which the intermediate transfer unit and the process cartridge are pulled out from the state of FIG. 9 and the damping material can be accessed from above. (A) is the graph which measured the vibration acceleration at the time of sheet conveyance in the conventional paper feed part structure, (b) is the graph which measured the vibration acceleration in the paper feed part structure of Example 1. FIG. FIG. 3 is a side view of the sheet feeding device showing a state where a sheet is being conveyed. FIG. 9 is a perspective view of a paper feed stay according to a second embodiment. FIG. 14 is a top view of the paper feed stay in FIG. 13. FIG. 9 is a perspective view of a paper feed stay according to a third embodiment. FIG. 16 is a top view of the paper feed stay in FIG. 15.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an external perspective view showing an example of the overall configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a structural cross-sectional view schematically showing the structure of the image forming apparatus of the present embodiment.

  As shown in FIG. 1, a laser printer 1 as an image forming apparatus according to this embodiment includes a paper feed tray 2 on which sheets S are stacked and stored, an upper cover 3 on which sheets S discharged from the apparatus are stacked, and can be opened and closed. The transfer cover 4 is provided. Further, as shown in FIG. 2, the laser printer 1 includes four process cartridges 5B, C, M, and Y, an intermediate transfer unit 6, a fixing unit 7, a conveying roller pair 21, a transfer roller 22, A paper discharge roller pair 23 and an optical unit 24 are provided. The laser printer 1 also includes a paper feed roller 60 as a feed member that separates and feeds the sheets S stacked on the paper feed tray 2 one by one.

  In the laser printer 1 having the above-described configuration, when a print job is input, the sheets S stacked on the paper feed tray 2 are fed to the transport path by the paper feed roller 60 and are passed through the transport roller pair 21 in FIG. It is transported to a transfer roller 22 positioned above in the vertical direction. Further, the process cartridges 5B, C, M, and Y are exposed by the optical unit 24 to form an image, and this image is transferred to the conveyed sheet S by the transfer roller 22 through the intermediate transfer unit 6. Further, the sheet S is fixed by the fixing unit 7 with heat and pressure, and is discharged to the upper cover 3.

  Next, a sheet feeding device as a sheet feeding device for feeding the sheets S stored in the sheet feeding tray 2 one by one will be described. FIG. 3 is a perspective view of the paper feed tray 2, and FIG. 4 is a side view of a paper feed separation unit of a general paper feed device using a separation pad system.

  As shown in FIG. 3, the paper feed tray 2 has a paper feed roller 60 rotatably supported by a paper feed stay 61 as a frame member, which will be described later. It shows the state.

  As shown in FIG. 4, the sheet feeding device is arranged on a sheet feeding roller 60, a stacking plate 54, a compression spring 56 that biases the sheet S on the stacking plate 54 toward the sheet feeding roller 60, a receiving table 52, and a receiving table 52. The separation pad 51 and the cradle 52 are provided with a separation spring 55 that urges the sheet receiving roller 60 toward the sheet feeding roller 60 side. The paper feed roller 60 is rotationally driven in the direction of the arrow in the figure by a drive source such as a motor. The separation pad 51 has a function as a sheet separation member disposed so as to be pressed against the paper feed roller 60. FIG. 4 illustrates a sheet feeding device having a rotation-type separation pad configuration in which the cradle 52 rotates about the rotation shaft 52b. However, the sheet feeding device is not limited to the rotation-type separation pad configuration. Alternatively, a direct acting separation pad configuration in which the cradle 52 translates in the vertical direction may be employed.

  The sheet S stacked on the stacking plate 54 in the sheet feeding tray 2 is pressed against the sheet feeding roller 60 by the pressure force of the compression spring 56 to form a sheet feeding nip. By driving 60, the uppermost sheet S is conveyed one by one. Here, a compression spring 56 is used as a means for pressing and biasing the stacking plate 54 toward the paper feed roller 60, but any configuration in which the paper feed roller 60 and the stacking plate 54 are in contact with each other to apply a pressing force. Any means may be used.

  In the sheet feeding device, when a plurality of sheets S stacked on the stacking plate 54 are fed by the sheet feeding roller 60, the plurality of sheets S are sandwiched in a separation nip between the sheet feeding roller 60 and the separation pad 51. It is. The separation nip is maintained in a state where a predetermined pressure is applied by the separation spring 55. Here, when the friction coefficient between the sheet feeding roller 60 and the sheet S is μr, the friction coefficient between the sheets S is μp, and the friction coefficient between the sheet S and the separation pad 51 is μf, these three frictions. The magnitude relationship of the coefficients is set so that μr> μf> μp. Thus, only the uppermost sheet S that is in contact with the sheet feeding roller 60 among the plurality of sheets S that have been fed is frictionally separated and fed toward the conveying roller pair 21. Further, as the material of the cradle 52, a resin material having a lower coefficient of friction than the separation pad 51 can be selected in order to improve the transportability of the sheet S.

[Example 1]
Next, an example of a support structure for the paper feed roller 60 and the damping material 63 will be described.
FIG. 5 is a perspective view of a paper feed stay 61 as a frame member that supports the paper feed roller 60 and the damping material 63 according to Example 1 of the present embodiment. FIG. 6 is a top view of the paper feed stay 61 of FIG. 5 as viewed from above. 7 is a cross-sectional view taken along the line AA in FIG.

  In the first exemplary embodiment, as illustrated in FIG. 7, the paper feed roller 60 includes a rubber roller portion 60a and a hub portion 60b that cover the outer periphery. Support shafts 60c and 60d are provided at both ends of the hub portion 60b. The support shaft 60 c is rotatably supported by a boss portion 61 a provided integrally with the paper feed stay 61, and the support shaft 60 d is rotatably supported by a hole portion 61 b provided integrally with the paper feed stay 61. . The support shaft 60c and the boss portion 61a, and the support shaft 60d and the hole portion 61b have a function as a holding portion that holds the paper feed roller 60 rotatably.

  Further, the leading end of the paper feed shaft 62 is fixed to the inner periphery of the support shaft 60d of the hub portion 60b. The paper feed shaft 62 is connected to a drive unit such as a motor via a gear or the like outside the paper feed stay 61 and is rotationally driven together with the paper feed roller 60 in the direction of the arrow in FIG. The driving force is transmitted from the driving unit to the sheet feeding roller 60 via the sheet feeding shaft 62, whereby the sheet feeding roller 60 rotates and the sheet S is conveyed.

  The holding unit is not limited to the above-described configuration, and may be configured such that the support shafts 60c and 60d of the paper feed roller 60 are rotatably supported by the paper feed stay 61 via bearings such as ball bearings.

  The paper feed stay 61 is held by side plates 70 and 71 provided on both sides. Further, the paper feed stay 61 is integrally provided with an upper wall 61 c that covers the upper portion of the paper feed roller 60.

  In the sheet feeding device configured as described above, a minute vibration may occur in the sheet S due to stick-slip between the sheet S and the separation pad 51 when the sheet is conveyed. Then, this minute vibration propagates to the paper feed stay 61 via the paper feed roller 60, and there is a possibility that abnormal noise may be generated due to resonance of the paper feed stay 61.

  Here, in the case where vibration is suppressed by providing a damping member on the receiving pad 52 or the paper feed tray 2 of the separation pad 51, vibrations of the separation pad 51, the receiving pad 52, and the paper feeding tray 2 can be suppressed. However, the occurrence of abnormal noise due to resonance of the sheet feeding stay 61 due to minute vibration of the sheet S due to the stick slip cannot be suppressed.

  Further, in the above-mentioned Patent Document 1, a damping material (vibration suppressing member) is not a receiving base or a sheet feeding tray but a sheet feeding provided coaxially with a sheet feeding roller for positioning the sheet feeding roller with respect to a separation pad. A sheet feeding device in which a damping material is provided on a side surface of the roller is disclosed. However, even with the sheet feeding apparatus of Patent Document 1, the occurrence of noise due to resonance of the sheet feeding stay 61 due to minute vibration of the sheet S due to the stick slip cannot be suppressed. Moreover, in the sheet feeding device of Patent Document 1, since the damping material is provided on the side surface of the sheet feeding roller, the gravity center position of the sheet feeding roller is shifted to cause rotation unevenness, and the sheet feeding apparatus is provided coaxially with the sheet feeding roller. Rotation unevenness may also occur in the paper feed roller, which may cause abnormal images and abnormal sounds. Furthermore, in the sheet feeding device of Patent Document 1, since the weight of the sheet feeding roller provided coaxially with the sheet feeding roller is increased to suppress vibration, the driving torque of the sheet feeding roller is increased. There is also a possibility that wear and damage with time due to an increase in torque, resulting in a shortened life and poor conveyance. In addition, depending on the rigidity and mass of the damping material parts, the mass of damping material required to change the natural frequency until the feed roller does not resonate is large. There is a case where a space cannot be secured in the side surface of the paper feed roller. In this case, it is necessary to increase the size of the paper feed roller and the paper feed roller.

  In the first exemplary embodiment, in order to prevent noise due to resonance of the paper feed stay 61 during separation and feeding in the paper feed device as the sheet feeding device, the damping material 63 as a vibration suppressing member is provided in the paper feed stay 61. Is installed. By installing the damping material 63 and increasing the load applied to the paper feed stay 61, the natural frequency of the paper feed stay 61 can be changed to prevent resonance. At this time, in order to change the natural frequency of the paper feed stay 61 with the vibration damping material 63, it is necessary to increase the mass as much as possible, and in order to efficiently obtain the noise prevention effect, the material of the vibration damping material 63 is required. It is desirable that the specific gravity is large. Therefore, in the first embodiment, a metal material having a specific gravity larger than that of the resin material is used as the vibration damping material 63. The shape of the damping material 63 is a rectangular plate material in the examples shown in FIGS. 5 to 7, but another shape such as a bar material may be used.

Next, the optimal installation position of the damping material 63 will be described.
In order to suppress the resonance of the paper feed stay 61, it is desirable to suppress the vibration on the upstream side of the propagation path as close to the vibration source as possible. The vibration that causes resonance of the paper feed stay 61 is propagated from the paper feed roller 60 to the paper feed stay 61 via the boss portion 61a and the hole portion 61b which are holding portions. Therefore, in the first exemplary embodiment, in FIG. 7, vibration suppression is performed on the upper surface side of the upper wall 61 c that covers the upper portion of the boss portion 61 a and the hole portion 61 b that are holding portions of the paper feed roller 60, that is, the upper portion of the paper feed roller 60. The material 63 is installed. Thus, by installing the damping material 63 on the upstream side of the propagation path, it is possible to further enhance the effect of preventing abnormal noise.

  Further, the paper feed stay 61 is formed with a cutout portion 61d as a cutout portion so that the paper feed roller 60 held by the support shaft 60c and the boss portion 61a and the support shaft 60d and the hole portion 61b is arranged. Has been. In the paper feed mechanism in which the paper feed nip and the separation nip are formed by the single paper feed roller 60 as in the first embodiment, in order to secure the nip amount between the paper feed unit and the separation unit, other conveyance is performed. The outer diameter is larger than that of the roller. Therefore, the cutout range of the paper feed stay 61 is also larger than the other conveyance roller installation locations. If the notch 61d is large as described above, the rigidity of the periphery is lowered, and the paper feed roller 60 and the paper feed stay 61 are likely to resonate. Therefore, in order to compensate for the rigidity of the paper feed stay 61, the outer surface of the notch 61d in which the paper feed roller 60 of the paper feed stay 61 is disposed is opposite to the paper feed roller 60, that is, the paper feed roller described above. A vibration damping material 63 having high rigidity is provided on the upper surface side of the upper wall 61c that covers the upper portion of 60. Thereby, the rigidity of the paper feed stay 61 can be ensured, and the effect of preventing abnormal noise can be further enhanced.

  In addition, since it is not the structure which provides the damping material in the side surface of a paper feed roller as it is disclosed by the said patent document 1, the gravity center position of a paper feed roller will shift | deviate and a rotation nonuniformity will not arise. Further, the paper feed roller does not increase in size in order to secure a sufficient installation space for the damping material in the paper feed roller.

  In the first embodiment, as shown in FIG. 7, the damping material 63 is fastened to the paper feed stay 61 with screws 64 a and 64 b. By connecting the vibration damping material 63 having high rigidity to the paper feed stay 61, it is possible to increase the rigidity of the paper feed stay 61 and reduce vibration. Further, the vibration damping material 63 can be easily attached to and detached from the paper feed stay 61 by screw fastening. In the first embodiment, screw fastening is used as a means for fixing the vibration damping material 63 to the paper feed stay 61, but it may be fixed by a double-sided tape, an adhesive, or a claw using resin elasticity. .

  Further, the vibration can be further reduced by providing the fixing portion of the damping material 63 at a position as close as possible to the vibration source as described above. In the first embodiment, screw holes 61g and 61h for screwing the damping material 63 are provided in the vicinity of the boss portions 61a and 61b close to the vibration source, respectively. In this way, the vicinity of both sides of the boss portion 61a holding the paper feed roller 60 and the hole portion 61b are screw-fixed and connected by the damping material 63, thereby increasing the rigidity around the paper feed roller 60. The effect of preventing abnormal noise can be further enhanced.

Next, a configuration in which a plurality (a plurality) of damping materials 63 can be installed and the number (number) of the damping materials 63 can be adjusted by detachment, that is, a configuration in which the load amount of the damping materials 63 can be adjusted will be described.
The above-described minute vibration called stick-slip varies in frequency and magnitude depending on the sheet material and environment used. For this reason, the natural frequency capable of suppressing the vibration of the paper feed stay 61 may differ depending on the use situation. In order to prepare for such a case, a plurality of (a plurality of) damping materials 63 can be installed, and the number (the number of sheets) can be adjusted by attaching and detaching the screws. Can be adjusted. Thereby, according to a user's use condition, it becomes possible to adjust the number (number of sheets) of the damping material 63, change a natural frequency, and to suppress abnormal noise.

  For example, when the vibration suppression effect is insufficient, it is possible to cope with adding a damping material 63. On the other hand, when the vibration suppression effect is sufficient or unnecessary, it is possible to reduce the machine weight by reducing or eliminating the number of damping materials 63. As a result, the vibration damping material 63 is not attached at the time of shipment, and if noise or vibration occurs during use by the user, it is possible to attach the vibration damping material 63 later. Therefore, it is possible to reduce the cost at the time of shipment and to reduce the weight of the apparatus.

  In the first embodiment, the plate-like vibration damping material 63 is stacked on top to adjust the number of stacked sheets, and the vibration damping material 63 to be used has the same shape. By unifying the types of damping material 63 into one, the work at the time of adjusting the number can be facilitated, and an increase in mold cost can be prevented. Further, screw through holes 63 a and 63 b are provided on the vibration damping material 63, and a plurality of vibration damping materials 63 can be fastened together to the paper feed stay 61. At this time, screws 64a and 64b having different lengths may be used according to the number of damping materials 63 used. If there is enough space, the screw holes 61g and 61h are sufficiently deep to form a female screw, and long screws 64a and 64b that can be fastened from one (sheet) to the maximum load number (number) are used. May be. Furthermore, by setting the height of the positioning bosses 61e and 61f on the paper feed stay 61 to be equal to or greater than the thickness of the maximum number of damping materials 63 (the number), it is possible to position a plurality of damping materials 63 together. become.

Next, the accessibility of the damping material 63 will be described.
In the configuration in which a plurality of damping materials 63 can be installed and the number of the damping materials 63 can be adjusted, in order to easily adjust the number of damping materials 63, access to the installation location of the damping material 63 is easy. It is desirable. In general, the paper feed roller 60 is often a consumable item and can be replaced, but the upper side of the paper feed roller 60 (the upper surface side of the paper feed stay 61) is often difficult to access inside the apparatus. If an opening is provided to allow access, the rigidity of the entire apparatus is reduced, and abnormal sounds and image defects may occur.

  Therefore, in the first embodiment, the damping material 63 is installed at a position where it can be accessed by removing the consumable unit that needs to be attached and detached. For this reason, it becomes possible to access the damping material 63 without providing an opening that lowers the rigidity of the entire apparatus.

A specific configuration capable of accessing the vibration damping material 63 described above will be described in detail with reference to FIGS.
FIG. 8 is a schematic sectional view of the laser printer 1 showing a state in which the upper cover 3 and the transfer cover 4 are closed. FIG. 9 is a schematic sectional view of the laser printer 1 showing a state in which the upper cover 3 and the transfer cover 4 are opened. FIG. 10 is a schematic cross-sectional view of the laser printer 1 showing a state in which the intermediate transfer unit 6 and the process cartridge 5 as the developing unit are pulled out from the state of FIG. It is.

  In FIG. 8, the intermediate transfer unit 6 and the process cartridge 5 are arranged above the vibration damping material 63. In FIG. 9, transfer units such as the transfer roller 22 and the intermediate transfer unit 6 can be detached in the forward direction (right direction in the figure) by opening the transfer cover 4. Further, the process cartridge 5 can be detached upward by opening the upper cover 3. Further, as shown in FIG. 10, the damping material 63 can be accessed from above by removing the intermediate transfer unit 6 and the black process cartridge 5B. Accordingly, the screws 64a and 64b, the ground plate 65, and the vibration damping material 63 can be easily attached / detached by a procedure similar to that for attaching / detaching other consumables without reducing the rigidity of the apparatus.

  Note that the method for detaching a consumable part such as the process cartridge 5 in the first embodiment is an example. For example, the process cartridge 5 is pulled out to the front side in FIG. 9, or the intermediate transfer unit 6 is removed from the side surface of the laser printer 1 main body. It may be pulled out to the front side. As described above, the process cartridge 5 and the intermediate transfer unit 6 may have different pulling directions, and these are detachably provided above the vibration damping material 63, and the vibration damping material 63 is exposed when it is pulled out. Any configuration may be used.

  Next, the ground configuration of the damping material 63 will be described. The material of the damping material 63 is a metal material having a large specific gravity, and the damping material 63 is connected to the ground in order to prevent noise to the intermediate transfer unit 6 and the sheet S due to discharge. In the first embodiment, one end of the ground plate 65 is brought into contact with the uppermost damping material 63 and fixed together with a plurality of other damping materials 63, and the other end is fixed to the paper feed stay 61 with a screw 64 c. . The ground plate 65 is connected from the paper feed stay 61 to the ground. The plurality of stacked damping materials 63 are in contact with each other on the upper surface and the lower surface, and all the damping materials 63 are electrically connected. Therefore, if ground is connected to the uppermost damping material 63, all the damping materials 63 can be grounded. Further, by using a flexible thin plate material as the material of the ground plate 65, the ground plate 65 can be deformed and follow even if the number of the damping materials 63 is changed, so that the ground plate 65 can be fixed.

Next, vibration acceleration during sheet conveyance of the sheet feeding device according to the first embodiment will be described in comparison with a sheet feeding device having a conventional configuration.
FIG. 11A is a graph (sample 1) obtained by measuring vibration acceleration during sheet conveyance in the sheet feeding unit configuration according to the comparative example, and FIG. 11B is a vibration in the sheet feeding unit configuration according to the first embodiment. It is the graph (sample 2) which measured the acceleration. The only difference in the configuration of these sheet feeding sections is the presence or absence of the damping material 63, and other structures and materials are set to the same setting. FIG. 12 is a side view of the sheet feeding device showing a state where the sheet S is being conveyed.

  The waveforms shown in FIGS. 11A and 11B are graphs of vibration measurement results before and after the sheet trailing edge Se passes through the sheet feeding nip A in a laser printer equipped with sheet feeding devices of both configurations. Yes, the horizontal axis represents time value [s], and the vertical axis represents vibration acceleration [G]. The larger the vibration acceleration [G] on the vertical axis, the greater the vibration of the paper feed stay 61, and the greater the noise that is generated. In this measurement, the paper feed roller 60 performs an operation of stopping driving after about 0.12 [s] after the trailing edge of the sheet passes through the paper feed nip.

As shown in FIG. 11A, in the graph (sample 1) showing the measurement result of the sheet feeding device having the conventional configuration, the sheet feeding roller 60 is stopped after the sheet trailing edge Se passes through the sheet feeding nip A. There is a lot of noise in between. The reason for the increase in vibration at this timing is that, after passing through the paper feed nip A, the separation pad 51 having a high friction coefficient (μ) and the paper feed roller 60 slide directly in the separation nip B and the paper feed roller. This is because the load applied to 60 increases.
On the other hand, as shown in FIG. 11B, in the graph (sample 2) showing the measurement result of the sheet feeding device according to the first embodiment, the same timing (sheet trailing edge Se passes through the sheet feeding nip A). Until the feed roller 60 stops), only minute vibrations are measured.

  From the above measurement results, it was confirmed that there was a large difference in vibration acceleration between the configuration of the sheet feeding device of the first embodiment and the conventional configuration, and that the sheet feeding device of the first embodiment generated only minute vibrations. Therefore, the paper feeding apparatus according to the first embodiment can obviously reduce vibration compared to the conventional configuration, and the effect of suppressing the vibration of the paper feeding stay 61 and suppressing / preventing the generation of abnormal noise. Proved that there is. The details of the equipment used for measurement of vibration acceleration are as shown in Table 1 below.

[Example 2]
Next, Example 2 of the present embodiment will be described.
FIG. 13 is a perspective view of the paper feed stay 61 according to the second embodiment. FIG. 14 is a top view of the paper feed stay 61 of FIG. 13 as viewed from above. The description of the same structure as in the first embodiment is omitted.

  As shown in FIGS. 13 and 14, the paper feed stay 61 according to the second embodiment is provided with four ribs 67a, b, c, and d as a plurality of protrusions. The damping material 63 is press-fitted into these four ribs 67 a, b, c, and d, and is fastened by screws 64 a and b and held by the paper feed stay 61.

  In the paper feed stay 61 according to the second embodiment, by providing the ribs 67a, b, c, and d, the rigidity of the paper feed stay 61 that holds the vibration damping material 63 is increased, and vibration can be further suppressed.

Example 3
Next, Example 3 of the present embodiment will be described.
FIG. 15 is a perspective view of the paper feed stay 61 according to the third embodiment. FIG. 16 is a top view of the paper feed stay 61 of FIG. 15 as viewed from above. The description of the same structure as that of the first embodiment is omitted.

As shown in FIGS. 15 and 16, the paper feed stay 61 according to the third embodiment is configured to press-fit and hold the damping material 63 into the four ribs 67 a, b, c, and d without screwing. It has become. Further, the plurality of vibration damping materials 63 are bonded to each other between the upper surface and the lower surface facing each other with an adhesive such as a double-sided tape.
In addition, since the plurality of vibration damping materials 63 are respectively bonded with an adhesive, the vibration damping material 63 itself is not electrically connected, but the ground plate 68 is attached to the loading side surface of each of the plurality of vibration damping materials 63. A plurality of damping materials 63 are collectively connected to the ground by abutting.

  In the paper feed stay 61 according to the third embodiment, since no fastening screw is used, parts and assembly costs can be reduced, and each of the plurality of damping materials 63 can be reliably connected to the ground. .

  The paper feeding device is not limited to the image forming device such as the laser printer 1 described above, and may be applied to an image reading device such as a scanner including an image reading unit such as an image sensor. This image reading apparatus can prevent abnormal noise and vibration when the sheet S is conveyed, and can read a high-quality image.

What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.
(Aspect A)
A feeding member such as a sheet feeding roller 60 that is rotationally driven to feed the sheet S, a sheet separating member such as a separation pad 51 disposed so as to be pressed against the feeding member, and a support for the feeding member A sheet feeding device such as a sheet feeding device including a boss portion 61a and a shaft support portion such as a hole portion 61b that rotatably support a shaft such as the shaft 60c, and a frame member provided with the shaft support portion. Further, a vibration suppressing member such as a damping material 63 for suppressing the vibration of the frame member is provided.
According to this, as described in Example 1 of the above-described embodiment, the vibration of the frame member is changed by changing the resonance point (natural frequency) of the frame member or increasing the rigidity of the frame member by the vibration suppressing member. Is suppressed. Since the vibration of the frame member is suppressed in this way, even if the vibration of the sheet generated by the stick slip between the sheet and the separation pad during sheet feeding propagates to the frame member via the feeding member and its shaft support portion. The vibration of the frame member is suppressed. By suppressing the vibration of the frame member in this manner, the occurrence of resonance of the frame member due to the stick slip can be suppressed. Accordingly, it is possible to prevent abnormal noise caused by resonance of the frame member due to stick slip between the sheet and the separation pad during sheet feeding.
(Aspect B)
In the aspect A, the vibration suppressing member is provided in the vicinity of the shaft support portion in the frame member.
According to this, since the vibration of the frame member can be suppressed in the vicinity of the shaft support portion of the feeding member close to the vibration source of the minute vibration between the sheet and the sheet separating member as described in the above embodiment, the frame The effect which suppresses the vibration of a member can be heightened more.
(Aspect C)
In the above aspect A or aspect B, the frame member is formed so as to have a notch portion that is notched so that the feeding member supported by the shaft support portion is disposed, and the vibration suppressing member is provided in the frame member. It is arrange | positioned on the outer surface on the opposite side to the feed member of the notch part by which the feed member was arrange | positioned.
According to this, since the vibration suppressing member is disposed on the outer surface of the cutout portion of the frame member as described in Example 1 of the above embodiment, the vibration of the frame member is increased while increasing the rigidity of the frame member. The effect which suppresses can be heightened more.
(Aspect D)
In any one of the aspects A to C, the vibration suppressing member is fixed to the frame member.
According to this, as described in Example 1 of the above-described embodiment, the effect of suppressing the vibration of the frame member is further improved while the rigidity of the frame member is increased by fixing the vibration suppressing member to the frame member. Can do. In addition, the vibration suppressing member can be more reliably prevented from falling.
(Aspect E)
In the aspect D, the vibration suppressing member is fixed in the vicinity of the shaft support portion in the frame portion.
According to this, as described in Example 1 of the above-described embodiment, by fixing the vibration suppressing member and the frame member in the vicinity of the holding portion of the feeding member close to the vibration source of minute vibration, The effect of suppressing vibration can be further enhanced.
(Aspect F)
In any of the above aspects A to E, the vibration suppressing member is configured to be removable from the frame member.
According to this, as described in Example 1 of the above-described embodiment, the vibration suppressing member can be attached and detached according to the occurrence of abnormal noise due to the resonance of the frame member. For example, when a noise is generated at the time of use by the user without attaching the vibration suppressing member at the time of shipment, it is possible to attach the vibration suppressing member later. Further, it is possible to reduce the cost and the weight at the time of shipment.
(Aspect G)
In any of the above aspects A to F, the frame member is configured to be capable of stacking a plurality of vibration suppressing members.
According to this, as described in Example 1 of the above-described embodiment, the load amount of the vibration suppression member is adjusted according to the occurrence of abnormal noise due to the resonance of the frame member, while reducing the size and weight of the device, Abnormal noise can be reliably prevented.
(Aspect H)
In any one of the above aspects A to G, the image forming apparatus further includes a desorption unit such as the intermediate transfer unit 6 configured to be demountable from the sheet feeding device, the desorption unit is disposed adjacent to the frame member, and the vibration suppressing member is the frame. It is provided between the member and the detachable unit.
According to this, as described in Example 1 of the above embodiment, the frame member on which the vibration suppressing member is disposed by removing the detachable unit is exposed and can be easily accessed. Therefore, it is possible to easily perform the work of attaching / detaching the vibration suppressing member and the work of adjusting the amount. In particular, in the configuration in which the vibration suppressing member is disposed on the upper surface side of the frame member, the vibration suppressing member can be attached and detached from the upper side of the apparatus, and the maintainability can be further improved.
(Aspect I)
In any one of the above aspects A to H, the vibration suppressing member is formed of a conductive material and connected to the ground.
According to this, as described in Example 1 and Example 3 of the above-described embodiment, it is possible to prevent the generation of noise due to the vibration suppressing member being in an electrically floating state.
(Aspect J)
In any of the above aspects A to I, the vibration suppressing member is press-fitted between a plurality of protrusions such as ribs 67a, b, c, d formed on the frame member.
According to this, as described in Example 2 and Example 3 of the above embodiment, the rigidity of the frame member can be further increased, so that the effect of suppressing the resonance of the frame member can be further enhanced.
(Aspect K)
The sheet feeding device according to any one of the above aspects A to J, and an image forming unit such as a process cartridge 5 that forms an image on the sheet S fed from the sheet feeding device.
According to this, as described in Examples 1 to 3 of the above embodiment, the sheet S to be image-formed is fed toward the image forming unit, and is generated at the contact portion between the sheet and the separation pad. The noise due to the resonance of the frame member due to the minute vibrations can be prevented.
(Aspect L)
The sheet feeding device according to any one of the above-described aspects A to J, and an image reading unit such as an image sensor that reads an image of the sheet S fed from the sheet feeding device.
According to this, as described in the above-described embodiment, it is caused by the minute vibration generated at the contact portion between the sheet and the separation pad when feeding the sheet S to be read toward the image reading unit. Abnormal noise due to resonance of the frame member can be prevented.

DESCRIPTION OF SYMBOLS 1 Laser printer 2 Paper feed tray 3 Upper cover 4 Transfer cover 5B, C, M, Y Process cartridge 6 Intermediate transfer unit 7 Fixing unit 51 Separation pad 52 Receptacle 54 Stacking plate 55 Separation spring 56 Compression spring 60 Feed roller 60c, d Support shaft 61 Paper feed stay 61a Boss portion 61b Hole portion 61c Upper wall 61d Notch portion 62 Paper feed shaft 63 Damping material 64a, b Screw 65, 68 Earth plate 67a, b, c, d Rib 70, 71 Side plate A Feeding nip B Separation nip S Sheet

JP 2006-062873 A

Claims (12)

A feeding member that is rotationally driven to feed the sheet;
A sheet separating member arranged to press against the feeding member;
A shaft feeding unit that rotatably supports the shaft of the feeding member, and a sheet feeding device comprising:
A sheet feeding apparatus, wherein a vibration suppressing member that suppresses vibration of the frame member is provided on the frame member provided with the shaft support portion. In the sheet feeding apparatus according to claim 1,
The sheet feeding device according to claim 1, wherein the vibration suppressing member is provided in the vicinity of the shaft support portion of the frame member. In the sheet feeding apparatus according to claim 1 or 2,
The frame member is formed so as to have a cutout portion cut out so that the feeding member supported by the shaft support portion is disposed;
The sheet feeding device according to claim 1, wherein the vibration suppressing member is disposed on an outer surface of the frame member on a side opposite to the feeding member in a notch portion where the feeding member is disposed. In the sheet feeding apparatus according to any one of claims 1 to 3,
The sheet feeding device, wherein the vibration suppressing member is fixed to the frame member. The sheet feeding apparatus according to claim 4, wherein
The sheet feeding device according to claim 1, wherein the vibration suppressing member is fixed in the vicinity of the shaft support portion of the frame member. In the sheet feeding apparatus according to any one of claims 1 to 5,
The vibration suppressing member is configured to be detachable from the frame member. In the sheet feeding apparatus according to any one of claims 1 to 6,
The sheet feeding device, wherein the frame member is configured to be capable of stacking a plurality of the vibration suppressing members. In the sheet feeding apparatus according to any one of claims 1 to 7,
A detachable unit configured to be detachable from the sheet feeding apparatus;
The desorption unit is disposed adjacent to the frame member;
The sheet feeding device, wherein the vibration suppressing member is provided between the frame member and the detachable unit. In the sheet feeding apparatus according to any one of claims 1 to 8,
The sheet feeding device, wherein the vibration suppressing member is formed of a conductive material and connected to a ground. In the sheet feeding apparatus according to any one of claims 1 to 9,
The sheet feeding apparatus, wherein the vibration suppressing member is press-fitted between a plurality of protrusions formed on the frame member.   An image forming apparatus comprising: the sheet feeding device according to claim 1; and an image forming unit that forms an image on a sheet fed from the sheet feeding device.   An image reading apparatus comprising: the sheet feeding device according to claim 1; and an image reading unit that reads an image of a sheet fed from the sheet feeding device.

Images