US20220411212A1

US20220411212A1 - Paper feeding mechanism

Info

Publication number: US20220411212A1
Application number: US17/359,723
Authority: US
Inventors: Toshiaki Oshiro; Naofumi Soga; Eizo KURITA; Kenji Takashima
Original assignee: Toshiba TEC Corp
Current assignee: Toshiba TEC Corp
Priority date: 2021-06-28
Filing date: 2021-06-28
Publication date: 2022-12-29

Abstract

According to one embodiment, a paper feeding mechanism includes a tray, a first roller, a second roller, a third roller, and a guide member. The tray supports a sheet. The first roller picks up the sheet from the tray. The second roller conveys the sheet picked up by the first roller. The third roller forms a nip that sandwiches the sheet between the second roller and the third roller. Relative positions of the third roller and the first and second rollers are set such that a convey reference surface of the sheet that is in contact with the first roller and the second roller and a flat surface of the nip are disposed on substantially the same flat surface. The guide member is between the nip and the first roller and intersects the convey reference surface.

Description

FIELD

Embodiments described herein relate generally to a paper feeding mechanism, a method of feeding paper without a squeal sound, and a quiet paper feeder.

BACKGROUND

An image forming apparatus includes a paper feeding mechanism that supplies sheets. The paper feeding mechanism includes a pickup roller, a paper feeding roller, and a separation roller. There is a case where a plurality of sheets overlap each other and are picked up by the pickup roller. The paper feeding roller and the separation roller perform separation and conveyance of overlapping sheets. In the separation and conveyance, a lower layer sheet is separated from an upper layer sheet, and only the upper layer sheet is conveyed. If the separation and conveyance are performed, there is a case where the overlapping sheets vibrate, and a paper squeal sound is generated. A paper feeding mechanism that can prevent the paper squeal sound is required.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic configuration view of an image forming apparatus;

FIG. 2 is a sectional view of a paper feeding mechanism;

FIG. 3 is a perspective view of an area around a third roller;

FIG. 4 is an explanatory view of an operation of the paper feeding mechanism; and

FIG. 5 is a sectional view of a main portion of the paper feeding mechanism.

DETAILED DESCRIPTION

In general, according to one embodiment, a paper feeding mechanism includes a tray, a first roller, a second roller, a third roller, and a guide member. The tray supports a sheet. The first roller picks up the sheet from the tray. The second roller conveys the sheet picked up by the first roller. The third roller forms a nip that sandwiches the sheet between the second roller and the third roller. Relative positions of the third roller and the first and second rollers are set such that a convey reference surface of the sheet that is in contact with the first roller and the second roller and a flat surface of the nip are disposed on substantially the same flat surface. The guide member is between the nip and the first roller and intersects the convey reference surface. According to another embodiment, a method of feeding paper without a squeal sound involves supporting a sheet with a tray; picking up the sheet from the tray with a first roller; conveying the sheet picked up by the first roller with a second roller; forming a nip that sandwiches the sheet between the second roller and a third roller, the third roller having a relative position to the first roller and the second roller such that a convey reference surface of the sheet that is in contact with the first roller and the second roller and a flat surface of the nip are disposed on substantially the same flat surface; and guiding the sheet using a guide member positioned between the nip and the first roller and intersecting the convey reference surface.
Hereinafter, the paper feeding mechanism of the embodiment will be described with reference to the drawings.
The following describes an example in which the paper feeding mechanism of the embodiment is adopted in a manual feeding unit of an image forming apparatus. The paper feeding mechanism of the embodiment may be adopted in a sheet supply section of the image forming apparatus.
FIG. 1 is a schematic configuration view of an image forming apparatus 1. The image forming apparatus 1 performs a process of forming an image on a sheet S.
The image forming apparatus 1 includes a housing 15, a scanner section 2, an image forming unit 3, a sheet supply section 4, a conveying section 5, a manual feeding unit 6, a paper discharge tray 7, a reversing unit 8, a control panel 9, and a control section 12.
The housing 15 forms an outer shape of the image forming apparatus 1.
The scanner section 2 reads image information of a copy target based on brightness and darkness of light and generates an image signal. The scanner section 2 outputs the generated image signal to the image forming unit 3.
The image forming unit 3 forms an output image with a recording material such as toner based on an image signal received from the scanner section 2 or an image signal received from the outside. Hereinafter, the output image is referred to as a toner image. The image forming unit 3 transfers the toner image onto the front surface of the sheet S. The image forming unit 3 heats and pressurizes the toner image on the front surface of the sheet S to fix the toner image onto the sheet S.
The sheet supply section 4 supplies the sheets S one by one to the conveying section 5 at the timing when the image forming unit 3 forms a toner image. The sheet supply section 4 has a supply tray 20, a first supply roller 21, a second supply roller 22, and a third supply roller 23.
The supply tray 20 stores the sheet S of a predetermined size and type.
The first supply roller 21 picks up the sheets S one by one from the supply tray 20. The second supply roller transports the sheet S picked up by the first supply roller 21 to the conveying section 5 toward the downstream side where the sheet S is conveyed. The third supply roller 23 is opposite to the second supply roller 22. The third supply roller 23 sandwiches the sheet S between the second supply roller 22 and the third supply roller 23.
The conveying section 5 conveys the sheet S supplied from the sheet supply section 4 to the image forming unit 3. The conveying section 5 includes a conveying roller 26 and a registration roller 27.
The conveying roller 26 conveys the sheet S supplied from the supply rollers 22 and 23 to the registration roller 27. The conveying roller 26 makes the distal end of the sheet S on the downstream side abut against a nip NA of the registration roller 27.
The registration roller 27 bends the sheet S at the nip NA to adjust the position of the distal end of the sheet S on the downstream side. The registration roller 27 conveys the sheet S according to the timing when the image forming unit 3 transfers the toner image to the sheet S.
The image forming unit 3 will be described.
As illustrated in FIG. 1 , the image forming unit 3 includes a plurality of image forming sections 30, a laser scanning unit 31, an intermediate transfer belt 32, a transfer section 33, and a fixing device 34.
The image forming section 30 includes a photoreceptor drum 35. The image forming section 30 forms a toner image corresponding to the image signal from the scanner section 2 or the outside, on the photoreceptor drum 35. The plurality of image forming sections 30 form the toner images by yellow, magenta, cyan, and black toners, respectively.
A charging device, a developing device, and the like are around the photoreceptor drum 35. The charging device charges the front surface of the photoreceptor drum 35. A developing device contains a developer containing yellow, magenta, cyan, and black toners. The developing device develops the electrostatic latent image on the photoreceptor drum 35. A toner image made by toner of each color is formed on the photoreceptor drum 35.
The laser scanning unit 31 scans the charged photoreceptor drum 35 with a laser beam L to expose the photoreceptor drum 35. The laser scanning unit 31 exposes the photoreceptor drum 35 of the image forming sections 30 of each color with different laser beams LY, LM, LC, and LK. The laser scanning unit 31 forms an electrostatic latent image on the photoreceptor drum 35.
The toner image on the front surface of the photoreceptor drum 35 is primarily transferred to the intermediate transfer belt 32.
The transfer section 33 transfers the toner image primarily transferred onto the intermediate transfer belt 32, onto the front surface of the sheet S at a secondary transfer position.
The fixing device 34 heats and pressurizes the toner image transferred to the sheet S to fix the toner image onto the sheet S.
The reversing unit 8 reverses the sheet S to form an image on the back surface of the sheet S. The reversing unit 8 reverses the sheet S discharged from the fixing device 34 upside down by switchback. The reversing unit 8 conveys the reversed sheet S toward the registration roller 27.
The sheet S on which the image is formed and which is discharged is placed on the paper discharge tray 7.
The control panel 9 is a part of an input section through which an operator inputs information for operating the image forming apparatus 1. The control panel 9 includes a touch panel and various hard keys.
The control section 12 controls each member of the image forming apparatus 1.
The manual feeding unit 6 and the paper feeding mechanism 40 will be described.
The manual feeding unit 6 supplies the sheets S manually fed to the tray to the conveying section 5 one by one. For example, the manual feeding unit 6 is on the side of the image forming apparatus 1. The paper feeding mechanism 40 of the embodiment is adopted in the manual feeding unit 6.
FIG. 2 is a sectional view of the paper feeding mechanism and is an enlarged view of part II of FIG. 1 . The paper feeding mechanism 40 includes a tray 47, a first roller 41, a second roller 42, a third roller 43, a guide member 60, and a support member 50.
The X direction, the Y direction, and the Z direction of the rectangular coordinate system are defined as follows. The X direction is a direction in which a first rotary shaft A of the first roller 41 and a second rotary shaft B of the second roller 42 are aligned side by side. The +X direction is a direction from the first rotary shaft A to the second rotary shaft B. There is a case where the +X direction is referred to as a downstream side, and the −X direction is referred to as an upstream side. The Y direction is a direction parallel to the second rotary shaft B. For example, the X direction and the Y direction are substantially horizontal directions. The Z direction is a direction perpendicular to the X direction and the Y direction. The Z direction is a direction in which the second rotary shaft B of the second roller 42 and a third rotary shaft C of a third roller 43 are aligned side by side. The +Z direction is a direction from the third rotary shaft C to the second rotary shaft B. For example, the Z direction is a substantially vertical direction and the +Z direction is an upward direction.
The upper surface of the tray 47 is parallel to the Y direction. The upper surface of the tray 47 is inclined in the −Z direction over the +X direction. A manually fed sheet S is placed on the upper surface of the tray 47. The tray 47 supports the sheet S. If the image forming apparatus 1 starts printing, the end portion of the tray 47 in the +X direction rises. The sheet S supported by the tray 47 comes into contact with the first roller 41.
The first roller 41 is a pickup roller. The first rotary shaft A of the first roller 41 is parallel to the Y direction. The outer circumference of the first roller 41 is covered with an elastic body. The first roller 41 is rotated and driven by the driving source. The first roller 41 rotates in a state of being in contact with the sheet S supported by the tray 47. The first roller 41 picks up the sheet S from the tray 47 on the downstream direction (+X direction).
The second roller 42 is a paper feeding roller. The second rotary shaft B of the second roller 42 is parallel to the Y direction. The outer circumference of the second roller 42 is covered with an elastic body. The second roller 42 is rotated and driven by the driving source. The second roller 42 forms a nip N that sandwiches the sheet S between the second roller 42 and the third roller 43. The sheet S picked up by the first roller 41 enters the nip N. The sheet S is conveyed to the downstream side (+X direction) by the rotation of the second roller 42 in a state of sandwiching the sheet S in the nip N.
The third roller 43 is a separation roller. The third rotary shaft C of the third roller 43 is parallel to the Y direction. The outer circumference of the third roller 43 is covered with an elastic body. The third roller 43 is pressed toward the second roller 42 by a spring 44. The third roller 43 forms the nip N that sandwiches the sheet S between the second roller 42 and the third roller 43. The third roller 43 is rotated in a driven manner by the rotation of the second roller 42 in a state where the nip N is formed.
FIG. 3 is a perspective view of an area around the third roller. The third roller 43 is supported by the support member via a torque limiter 45. If a torque exceeding a predetermined value acts on the third roller 43, the torque limiter 45 allows the third roller 43 to rotate. If a torque that is equal to or lower than a predetermined value acts on the third roller 43, the torque limiter 45 prohibits the rotation of the third roller 43.
FIG. 4 is an explanatory view of an operation of the paper feeding mechanism. The coefficient of friction between the second and third rollers 42 and 43 and the sheet S is large. If one sheet S enters the nip N, the torque acting on the third roller 43 due to the rotation of the second roller 42 is greater than a predetermined value. The third roller 43 is allowed to rotate, and the sheet S is conveyed to the downstream side.
There is a case where a plurality of sheets SU and SD are picked up from the tray 47 in an overlapping state. The second roller 42 and the third roller 43 perform separation and conveyance of the overlapping sheets SU and SD. In the overlapping sheets SU and SD, the coefficient of friction between the upper layer sheet SU and the lower layer sheet SD is small. If a plurality of sheets S enter the nip N, the torque acting on the third roller 43 due to the rotation of the second roller 42 is smaller than a predetermined value. The rotation of the third roller 43 is prohibited, and the conveyance of the lower layer sheet SD is prevented by the third roller 43. Only the upper layer sheet SU is conveyed to the downstream side by the rotation of the second roller 42. The third roller 43 separates the lower layer sheet SD from the upper layer sheet SU.
FIG. 5 is a sectional view of the main portion of the paper feeding mechanism, and an enlarged view of part V of FIG. 2 . A nip surface NS, which is a flat surface of the nip N, is formed between the second roller 42 and the third roller 43. The flat surface which comes into contact with the second roller 42 and the first roller 41 from below, where the nip surface NS is formed, is a convey reference surface T of the sheet S. The sheet S is conveyed along the convey reference surface T. The relative positions of the first and second rollers 41 and 42 and the third roller 43 are set such that the convey reference surface T and the nip surface NS are disposed on substantially the same flat surface. A flat surface AB having the first rotary shaft A and the second rotary shaft B of the first roller 41 intersects a flat surface BC having the second rotary shaft B and the third rotary shaft C at a substantially right angle. The diameter of the first roller 41 and the diameter of the second roller 42 are substantially equivalent.
The guide member 60 is formed in a thin plate shape from a resin material such as polyethylene terephthalate or a metal material such as stainless steel. The guide member 60 is an elastic body and can be bent. The guide member 60 is parallel to the Y direction. The guide member 60 is inclined in the +Z direction over the +X direction. The guide member 60 intersects the convey reference surface T. A first end portion 61 in the −X direction of the guide member 60 is in the −Z direction of the convey reference surface T. The first end portion 61 is fixed to the support member 50. The relative positions of the first end portion 61 and the second rotary shaft B of the second roller 42 are fixed. A second end portion 62 in the +X direction of the guide member 60 is in the +Z direction of the convey reference surface T. The second end portion 62 is near the second roller 42 and the nip N. The relative positions of the second end portion 62 and the second rotary shaft B are not fixed.
As illustrated in FIG. 4 , there is case where the plurality of sheets SU and SD are picked up from the tray 47 in an overlapping state. The second roller 42 and the third roller 43 perform separation and conveyance of the overlapping sheets SU and SD. The guide member 60 intersects the convey reference surface T. The second end portion 62 of the guide member 60 abuts against the lower layer sheet SD and bends. The elasticity restoring force of the guide member 60 presses the lower layer sheet SD toward the upper layer sheet SU. The vibration of the overlapping sheets SU and SD is prevented, and the generation of paper squeal sound during the separation and conveyance is prevented.
The support member 50 rotatably supports the third roller 43. As illustrated in FIG. 5 , the support member 50 has a first surface 51 and a second surface 55.
The first surface 51 is a guide surface that guides the movement of the sheet S to the nip N. The first surface 51 is parallel to the Y direction. The first surface 51 is inclined in the +Z direction over the +X direction. The first surface 51 has an opening 53. A part of the third roller 43 protrudes in the +Z direction of the first surface 51 from the opening 53. The guide member 60 covers a part of the outer circumference of the protruding third roller 43. As illustrated in FIG. 3 , the width of the guide member 60 in the Y direction is greater than the width of the third roller 43 in the Y direction.
The second end portion 62 of the guide member 60 has a straight line shape which is substantially parallel to the Y direction. The exposure of the third roller 43 in the +Z direction is prevented by the guide member 60. As illustrated in FIG. 4 , the sheet S approaches the nip N along the guide member 60 and then comes into contact with the third roller 43. Turning-up and deformation of the distal end of the sheet S caused by plunging into the third roller 43 are prevented.
The first surface 51 has a recess portion 52 that is recessed in the −Z direction. As illustrated in FIG. 5 , the recess portion 52 is in the −X direction of the opening 53. The first end portion 61 of the guide member 60 is fixed to the bottom surface of the recess portion 52. The first end portion 61 is on the opposite side of the convey reference surface T across the first surface 51. The first end portion 61 is farther from the convey reference surface T than the first surface 51. If the sheet S picked up from the tray 47 abuts against the first surface 51, the sheet S does not get caught on the first end portion 61, and thus, the deformation of the sheet S is prevented.
The flat surface having the sheet S which is supported by the tray 47 and is in contact with the first roller 41 is a pick-up surface P. The sheet S is picked up from the tray 47 along the pick-up surface P by the first roller 41. The pick-up surface P is parallel to the Y direction. The pick-up surface P is inclined in the −Z direction over the +X direction. The first surface 51 intersects the pick-up surface P. Apart of the downstream side (+X direction) of the first surface 51 is on the side of the nip N of the pick-up surface P. The second end portion 62 of the guide member 60 is also on the side of the nip N of the pick-up surface P.
The sheet S picked up along the pick-up surface P abuts against the guide member 60 and the first surface 51, and moves to the nip N along the guide member 60 and the first surface 51. The sheet S is easily guided into the nip N by the first surface 51 and guide member 60. If the overlapping sheets SU and SD move along the guide member 60 and the inclined surface of the first surface 51, air is introduced between the overlapping sheets SU and SD. Before the overlapping sheets SU and SD reach the third roller 43, the overlapped sheets SU and SD are handled. The performance of separating and conveying the overlapping sheets SU and SD is improved.
The second end portion 62 of the guide member 60 is on the opposite side of the pick-up surface P across the first surface 51. The second end portion 62 is farther from the pick-up surface P than the first surface 51. The contact of the sheet S with the third roller 43 is controlled by the guide member 60. Turning-up and deformation of the distal end of the sheet S caused by plunging into the third roller 43 are prevented.
The second surface 55 is a support surface that supports the distal end of the sheet S accommodated in the tray 47. The second surface 55 is parallel to the Y direction and the normal direction of the pick-up surface P. There is a space between the second surface 55 and the distal end of the tray 47 in the +X direction. A rib 56 protrudes from the second surface 55 toward the tray 47. The height of the rib 56 is substantially constant. The rib 56 is parallel to the normal direction of the pick-up surface P. As illustrated in FIG. 3 , a plurality of ribs 56 are disposed at intervals in the Y direction. The distal end of the sheet S accommodated in the tray 47 in the +X direction abuts against the ribs 56 due to gravity. If the tray 47 rises toward the first roller 41, the distal end of the sheet S slides against the ribs 56 and does not slide against the second surface 55. The load caused by the sliding of the sheet S is reduced, and the tray 47 easily rises.
The sheet S picked up along the pick-up surface P abuts against the first surface 51. There are no ribs on the first surface 51. The deformation of the sheet S due to collision with the ribs is suppressed.
As described above, the paper feeding mechanism 40 of the embodiment includes the tray 47, the first roller 41, the second roller 42, the third roller 43, and the guide member 60. The tray 47 supports the sheet S. The first roller 41 picks up the sheet S from the tray 47. The second roller 42 conveys the sheet S picked up by the first roller 41. The third roller 43 forms the nip N that sandwiches the sheet S between the second roller 42 and the third roller 43. The relative positions of the third roller 43 and the first and second rollers 41 and 42 are set such that the convey reference surface T of the sheet S that is in contact with the first roller 41 and the second roller 42 and the nip surface NS are disposed on substantially the same flat surface. The guide member 60 is between the nip N and the first roller 41, and intersects the convey reference surface T.
There is a case where a plurality of sheets SU and SD are picked up from the tray 47 in an overlapping state. The second roller 42 and the third roller 43 perform separation and conveyance of the overlapping sheets SU and SD. Since the guide member 60 intersects the convey reference surface T, the guide member 60 abuts against the overlapping sheets SU and SD. The vibration of the overlapping sheets SU and SD is prevented, and the generation of paper squeal sound during the separation and conveyance is prevented.
The convey reference surface T and the nip surface NS are on substantially the same flat surface. The sheet S conveyed along the convey reference surface T is not curved on the nip surface NS. A part of the pressing force of the third roller 43 against the second roller 42 is not offset by the elasticity restoring force of the sheet S. The second roller 42 and the third roller 43 implement high separation and conveyance performance. Since the sufficient pressing force acts on the overlapping sheets SU and SD, the generation of paper squeal sound during the separation and conveyance is prevented.
The relative positions of the first end portion 61 of the guide member 60 and the second rotary shaft B are fixed, and the relative positions of the second end portion 62 and the second rotary shaft B are not fixed. The guide member 60 is a plate-shaped elastic body.
The second end portion 62 of the guide member 60 abuts against the lower layer sheet SD and bends. The elasticity restoring force of the guide member 60 presses the lower layer sheet SD toward the upper layer sheet SU. The vibration of the overlapping sheets SU and SD is prevented, and the generation of paper squeal sound during the separation and conveyance is prevented.
Even if the guide member 60 abuts against the sheet S such as a rigid cardboard, the guide member 60 bends, and accordingly, conveyance resistance of the sheet S is unlikely to be achieved. Deterioration of conveyance performance, such as conveyance delay of the sheet S, is prevented.
The paper feeding mechanism of the embodiment is adopted in the image forming apparatus, which is an example of an image processing apparatus. The paper feeding mechanism of the embodiment is adopted in a decoloring device, which is another example of an image processing apparatus. The decoloring device decolors (erases) the image formed on the sheet by the decoloring toner.
According to at least one embodiment described above, by providing the guide member 60 intersecting the convey reference surface T, the generation of paper squeal sound can be prevented.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.

Claims

What is claimed is:

1. A paper feeding mechanism, comprising:

a tray that supports a sheet;

a first roller that picks up the sheet from the tray;

a second roller that conveys the sheet picked up by the first roller;

a third roller which forms a nip that sandwiches the sheet between the second roller and the third roller, the third roller having a relative position to the first roller and the second roller set such that a convey reference surface of the sheet that is in contact with the first roller and the second roller and a flat surface of the nip are disposed on substantially the same flat surface; and

a guide member between the nip and the first roller and intersects the convey reference surface.

2. The paper feeding mechanism according to claim 1, wherein

relative positions of a first end portion of the guide member on the upstream side of the sheet in a conveying direction and a rotary shaft of the second roller are fixed, and

relative positions of a second end portion of the guide member on the downstream side of the sheet in the conveying direction and the rotary shaft of the second roller are not fixed.

3. The paper feeding mechanism according to claim 2, wherein

the guide member comprises an elastic body.

4. The paper feeding mechanism according to claim 2, wherein

the guide member has a plate shape.

5. The paper feeding mechanism according to claim 2, wherein

the second end portion of the guide member has a straight line shape substantially parallel to the rotary shaft of the second roller.

6. The paper feeding mechanism according to claim 2, further comprising:

a support member having a first surface that guides movement of the sheet into the nip, and

the first end portion of the guide member is on an opposite side of the convey reference surface sandwiching the first surface.

7. The paper feeding mechanism according to claim 6, wherein

if the flat surface having the sheet which is supported by the tray and in contact with the first roller is a pick-up surface, the first surface intersects the pick-up surface, and

the second end portion of the guide member is on a same side of the nip of the pick-up surface.

8. The paper feeding mechanism according to claim 7, wherein

the second end portion of the guide member is on an opposite side of the pick-up surface sandwiching the first surface.

9. The paper feeding mechanism according to claim 6, wherein

the support member comprises a rib that protrudes toward the tray.

10. The paper feeding mechanism according to claim 6, with the proviso that the support member does not have a rib on the first surface.

11. An image forming apparatus comprising the paper feeding mechanism according to claim 1.

12. A method of feeding paper without a squeal sound, comprising:

supporting a sheet with a tray;

picking up the sheet from the tray with a first roller;

conveying the sheet picked up by the first roller with a second roller;

forming a nip that sandwiches the sheet between the second roller and a third roller, the third roller having a relative position to the first roller and the second roller such that a convey reference surface of the sheet that is in contact with the first roller and the second roller and a flat surface of the nip are disposed on substantially the same flat surface; and

guiding the sheet using a guide member positioned between the nip and the first roller and intersecting the convey reference surface.

13. The method of feeding paper according to claim 12, wherein

14. The method of feeding paper according to claim 13, wherein

the guide member comprises an elastic body.

15. The method of feeding paper according to claim 13, wherein

the guide member has a plate shape.

16. The method of feeding paper according to claim 13, wherein

17. The method of feeding paper according to claim 13, further comprising:

that guiding movement of the sheet into the nip using a first surface of a support member, and

18. A quiet paper feeder, comprising:

a tray that supports a plurality of sheets;

a first roller that picks up a sheet from the tray;

a second roller that conveys the sheet picked up by the first roller;

19. The quiet paper feeder according to claim 18, wherein

20. The quiet paper feeder according to claim 19, wherein

the guide member comprises an elastic body and has a plate shape.