JP2004331381A - Paper feeding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an easily manufacturable paper feeding device capable of suppressing slight vibration of a separation pad due to friction with a sheet material to prevent the occurrence of noise. <P>SOLUTION: Since a part which opposes to a deep bottom channel part 48a<SB>2</SB>of a pad holder 48 of the separation pad 47 and is a nip part abutting on a paper feeding roller 45 is not bonded on a bottom face of the deep bottom channel part 48a<SB>2</SB>, a not-bonded part of the separation pad 47 is freely and elastically elongated and deformed even if the separation pad 47 made of an elastic material such as rubber attempts to warp while being restrained due to friction resistance between paper and the separation pad 47 when feeding paper 7 by rotation of the paper feeding roller 45, thereby suppressing restraint distortion of the separation pad 47. Consequently, slight vibration due to distortion of the separation pad 47 likely to occur when the whole bottom face of the separation pad 47 is bonded on the bottom face of the channel part 48a is suppressed to prevent the occurrence of noise due to slight vibration. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is used for a sheet feeding device of an image forming apparatus such as a copying machine, a printer, and a facsimile, and accommodates a sheet material such as a recording medium for recording an image such as paper and a document such as a paper on which the image is recorded. And belongs to the technical field of a sheet feeding device having a separation pad for feeding a sheet material one by one while preventing double feeding of a plurality of sheet materials. In particular, the separation pad is detachable from the sheet feeding device main body. The present invention belongs to the technical field of a sheet feeding device which is attached and is brought into contact with a sheet feeding roller.
[0002]
[Prior art]
Conventionally, in a sheet feeding device of an image forming apparatus as described above, a sheet feeding roller is rotated in a state in which a stored sheet material is pushed up by a lift plate and an uppermost sheet material is brought into contact with the sheet feeding roller. By doing so, for example, the uppermost sheet material is fed. At this time, a separation pad is provided in order to prevent a plurality of sheets from being double fed. When a plurality of sheet materials are fed by the feed roller, the separation pad separates the sheet materials other than the uppermost sheet material by friction or the like to prevent the sheet materials from being fed. , Only the uppermost sheet material is fed.
[0003]
By the way, when the sheet material fed from the sheet feeding device has a too high friction with the separation pad like the OHP sheet, that is, when the sheet material has high adhesion, it becomes difficult to separate the sheet material by the separation pad. In view of the above, a paper feeder that can reliably separate sheets by reducing friction between the separation pad and the sheet material even if the sheet material has high adhesion to the separation pad such as an OHP sheet is proposed. (For example, see Patent Document 1).
In this paper feeder, a cut is provided without any gap in the direction perpendicular to the feed direction on the feed surface side of the sheet material in the separation pad, and the frictional force between the separation pad and the sheet is reduced for a sheet having high adhesion. In this way, various kinds of sheet materials can be stably separated by performing reliable separation on a sheet with low adhesion, and by performing reliable separation with a sufficient frictional force as in the past. It is designed to be transported separately.
[Patent Document 1]
Japanese Patent No. 3155904 (paragraph numbers [0072], [FIG. 1], [FIG. 3], etc.)
[0004]
[Problems to be solved by the invention]
However, in the separation pad of the sheet feeding device disclosed in Patent Document 1, the entire surface of the separation pad is in close contact with the pad holder. Therefore, when the sheet material is fed by the rotation of the paper feed roller, the separation pad as a whole tends to be distorted while being restrained due to the frictional resistance between the sheet material and the separation pad. Then, it is conceivable that such a distortion of the separation pad may cause a minute vibration of the separation pad to generate a sound.
In addition, since there is a need to provide a notch with no gap in the separation pad, there is also a problem that the processing for manufacturing the separation pad becomes complicated.
[0005]
The present invention has been made in view of such circumstances, and an object of the present invention is to suppress minute vibration of a separation pad due to friction with a sheet material, prevent generation of noise, and simplify manufacturing. The purpose of the present invention is to provide a simple paper feeder.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a paper feeding device according to the first aspect of the present invention includes a paper feeding roller rotatably provided on a paper feeding device main body, and the paper feeding device slidably provided on a paper feeding device main body, A supply unit including at least a pad holder for supporting a separation pad in contact with a paper roller and urging means for urging the pad holder toward the paper supply roller to press the separation pad against the paper supply roller; In the paper device, a groove portion is formed at a position of the pad holder corresponding to a nip portion where the paper feed roller and the separation pad are in contact with each other at the separation pad supporting position of the pad holder. Of the bottom surface of the pad, the bottom surface portion facing the groove is not in close contact with the pad holder, and the bottom surface of the separation pad other than the bottom surface portion facing the groove is the pad portion. It is characterized in that it is in close contact with the holder.
[0007]
The invention of claim 2 is characterized in that the groove is provided directly on the pad holder.
Further, the invention of claim 3 is characterized in that a spacer member having an opening is provided at the separation pad supporting position of the pad holder, and the groove is formed by the opening of the spacer member. .
[0008]
Function and Effect of the Invention
In the sheet feeding device of the present invention configured as described above, when the sheet material is fed by the rotation of the sheet feeding roller, the separation pad is trying to be distorted while being restrained by the frictional resistance between the sheet material and the separation pad. Also, since the bottom surface portion of the separation pad, which faces the groove and is in contact with the paper feed roller, is not in close contact with the bottom surface of the groove, the portion of the separation pad corresponding to this bottom surface portion can be freely formed. It becomes elastically elongated and deformed. Thereby, restraint distortion of the separation pad is suppressed. Therefore, the minute vibration due to the restrictive strain of the separation pad, which is likely to occur when the entire bottom surface of the separation pad is stuck to the bottom surface of the groove, is suppressed, and the generation of sound due to the minute vibration is prevented. In particular, when the recording medium fed by the paper feed roller is an OHP sheet, the frictional resistance between the OHP sheet and the separation pad is large, so that the restrictive distortion of the separation pad is more effectively suppressed, Vibration and the generation of sound due thereto are more reliably prevented. In addition, since the bottom surface of the separation pad other than the bottom surface of the separation pad facing the groove is in close contact with the bottom surface of the groove, the rotation of the paper feed roller is smaller than when the entire bottom surface of the separation pad is not in close contact with the pad holder. The separation pad does not move relative to the pad holder at the time of feeding the sheet material. Therefore, the sheet material can be reliably and stably fed.
[0009]
In addition, the groove can be formed together with the pad holder when the pad holder is formed, and the separation pad does not need to process a large number of cuts as in the conventional example described above, so that both the separation pad and the pad holder can be easily manufactured. can do.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a view schematically showing an image forming apparatus provided with a first example of an embodiment of a sheet feeding device according to the present invention.
[0011]
As shown in FIG. 1, an image forming apparatus 1 of this example is generally exposed by an exposure unit 2, a developing unit 3 such as a rotary developing device, and an exposure unit 2 to form an electrostatic latent image. At the same time, the electrostatic latent image is developed with toner from the developing unit 3 to form a toner image, an intermediate transfer medium 5 including an endless transfer belt, and a toner image on the image carrier 4 in an intermediate state. A primary transfer unit 6 for primary transfer onto the transfer medium 5 and a toner image primary-transferred onto the intermediate transfer medium 5 are transferred to a recording medium (hereinafter, paper is used as an example for convenience of explanation) 7 as a sheet material such as paper. A secondary transfer unit 8 for next transfer, a paper feeding device 9 for feeding the stored paper 7 to the secondary transfer unit 8, a fixing unit 10 for fixing a toner image secondary-transferred to the paper 7, and a fixing unit 10 Where is established in It consists discharge tray 11 on which the image of accommodating the paper 7 which is formed.
In this case, the image forming apparatus 1 includes a first conveyance path 12 that conveys the paper 7 from the paper supply device 9 to the paper output tray 11 via the secondary transfer unit 8 and the fixing unit 10, A second transport path 13 is provided for reversing the paper 7 discharged from the fixing unit 10 and having a fixed image formed on one side thereof so that secondary transfer can be performed on the other side and transporting the paper 7 to the secondary transfer unit 8 again. .
[0012]
The paper feeding device 9 includes two first and second cassettes 14 and 15 that respectively store the paper 7, and the first and second cassettes 14 and 15 are arranged in two upper and lower tiers. The first and second cassettes 14 and 15 are both inserted into and mounted on the image forming apparatus main body 1a from the right in FIG. 1, and are pulled out from the image forming apparatus main body 1a to the right and removed. It has become. Each of the first and second cassettes 14 and 15 is formed as a telescopic cassette which can expand and contract between a shortened state shown by a solid line in FIG. 1 and an expanded state shown by a two-dot line in FIG. .
[0013]
In the present invention, the number of cassettes is not limited to two, and one or more cassettes can be provided in an arbitrary number. When a plurality of cassettes are provided, the cassettes are arranged in a plurality of upper and lower stages. In this case, a desired plurality of cassettes can be fixed to the desired number from the beginning in the image forming apparatus main body 1a, or a predetermined number of cassettes are disposed in the image forming apparatus main body 1a, and thereafter, In addition, one or more desired numbers can be further added. In this description, it is assumed that the image forming apparatus 1 includes two first and second cassettes 14 and 15 for convenience of description. The first cassette 14 is a main body cassette provided in the image forming apparatus main body 1a from the beginning, and the second cassette 15 is an additional cassette provided below the first cassette 14. In this case, in the present invention, the main body extension portion to which the second cassette 15 is mounted is also the image forming apparatus main body 1a.
[0014]
The first and second cassettes 14 and 15 have substantially the same basic configuration except for their depths. Therefore, the second cassette 15 which is an additional cassette will be described, and the description of the first cassette 14 will be omitted.
2 shows the second cassette 15 in an extended state, (a) is a top view, (b) is a bottom view, and FIG. 3 shows the second cassette 15 in a shortened state, (a) A top view and (b) are bottom views.
[0015]
As shown in FIGS. 2 (a) and 2 (b) and FIGS. 3 (a) and 3 (b), the second cassette 15 includes a cassette body (corresponding to the paper feeding apparatus body of the present invention) 16 and a cassette extension section 17. It is composed of The cassette body 16 includes a bottom 16a, left and right side walls 16b and 16c erected on both right and left sides of the bottom 16a, and a front side of the bottom 16a (the right side of the image forming apparatus 1 in FIG. 1; the lower side in FIG. 2). And a front wall 16d standing upright. The left side wall 16b has a double side wall arranged at a predetermined gap. Although not shown, the right side wall 16c is also formed in the same shape as the left side wall 16b, and in the case of the right side wall 16c, it is symmetrical with the shape of the left side wall 16b.
[0016]
Further, the cassette extension portion 17 includes a bottom portion 17a, left and right side walls 17b and 17c erected on both left and right sides of the bottom portion 17a, and a rear side of the bottom portion 17a (a back side of the image forming apparatus 1; ) Is provided on the rear wall 17d.
Then, the left and right side walls 17b and 17c of the cassette extension 17 are slidably inserted into or drawn out of the gaps between the corresponding left and right side walls 16b and 16c of the cassette body 16, so that the cassette extension 17 is inserted into the cassette. It is provided so as to be able to contract or expand by moving relative to the main body 16.
[0017]
Further, as shown in FIGS. 2A and 3A, a pair of left and right lock levers 18 and 19 are provided at the rear end of the cassette body 16 so as to be movable in the left and right directions, respectively. These lock levers 18 and 19 lock the cassette main body 16 and the cassette extension portion 17 so that they cannot move relative to each other in the extended state and the contracted state.
[0018]
As shown in FIG. 2A, the locking projection 21 of the left lock lever 18 can be selectively fitted into the left locking grooves 17g, 17g provided in the cassette extension 17, Further, the lock projection 21 of the right lock lever 19 can be selectively fitted into the right lock grooves 17h and 17i provided in the cassette extension portion 17.
[0019]
As shown in FIGS. 1, 2A, and 3A, the cassette body 16 is provided with a metal lift plate 26 that pushes the front end of the paper 7 upward. Left and right rotating arms 27 and 28 are provided on the left and right side edges on the rear end side of the lift plate 26 so as to protrude upward. As shown in FIG. 2A, the rotating arms 27 and 28 are supported by left and right side walls 16b and 16c of the cassette body 16 so as to be rotatable around left and right rotating shafts 29a and 29b, respectively. The lift plate 26 is constantly urged in the rising direction by a leaf spring (not shown).
[0020]
On the other hand, as shown in FIG. 2A, a metal slide plate 30 is provided at the left and right center positions of the cassette extension portion 17 on left and right guides 31 and 32 extending in the longitudinal direction (front-rear direction) of the cassette extension portion 17. It is provided so that it can slide along. In this case, as shown in FIGS. 2 (a) and 2 (b) and FIGS. 3 (a) and 3 (b), a compression spring 33 is contracted between the cassette extension portion 17 and the slide plate 30, and the compression spring 33 is compressed. The slide plate 30 is constantly urged rearward by the spring force of the spring 33.
[0021]
At the left and right center positions of the slide plate 30, a rear end guide 34 for supporting the rear end of the paper 7 is provided upright so as to be movable along the longitudinal direction of the cassette extension portion 17. The rear end guide 34 is adjusted and positioned at an arbitrary position in the longitudinal direction (front-back direction) of the set extension 17. In that case, the same positioning mechanism as the positioning mechanism of the rear end guide provided in the conventional paper feed cassette can be used, and a description thereof will be omitted.
[0022]
As shown in FIGS. 2A and 3A, the lift plate 26 and the slide plate 30 are connected by left and right connection members 39 and 40.
As shown in FIGS. 4A to 4D, the connecting hooks 43 of the lift plate 26 are always connected to the corresponding lift plate connecting portions 41 of the left and right connecting members 39 and 40, respectively. In this case, the connecting hook 43 and the lift plate connecting portion 41 are connected so that the connecting members 39 and 40 can relatively move in the left-right direction with respect to the lift plate 26. As shown in FIGS. 2A and 3A, the slide plate connecting portions 42 of the left and right connecting members 39, 40 are provided on the arms 30a, 30b, 30c, 30d of the slide plate 30, respectively. In addition, the connection grooves 37 and 38 (the connection grooves of the arms 30a and 30b are not shown in the figure) can be selectively fitted and removed (this fitting operation will be described later). In this case, the slide plate 30 and the connection members 39 and 40 are connected to each other by fitting the slide plate connection portions 42 into the corresponding connection grooves.
[0023]
Thus, the lift plate 26 and the slide plate 30 are connected to each other via the connection members 39 and 40 by connecting the slide plate 30 and the connection members 39 and 40 to each other. This allows the slide plate 30 to move back and forth in conjunction with the up and down rotation of the lift plate 26.
[0024]
Therefore, as shown in FIGS. 4A to 4D, the slide plate connecting portions 42 of the connecting members 39 and 40 correspond to the second cassette 15 in either the extended state or the contracted state. When the lift plate 26 is turned in the prone direction and is in the prone position shown by a solid line substantially parallel to the bottom 16a of the cassette body 16 in a state fitted in the connection grooves 37, 38, the slide plate 30 It moves rearward in conjunction with the rotation of the lift plate 26 in the downward direction, and is held at the rearmost position where it abuts against the rear wall 17 d of the cassette extension 17.
[0025]
When the lift plate 26 and the slide plate 30 are connected to each other via the connection members 39 and 40, the slide plate 30 is constantly urged rearward by the spring force of the compression spring 33 as described above. The lift plate 26 is urged in the downward direction by the spring force of the compression spring 33. However, since the urging force for urging the lift plate 26 in the rising direction is larger than the urging force of the lift plate 26 due to the spring force of the compression spring 33, the lift plate 26 is urged in the rising direction. I have.
[0026]
As shown in FIGS. 4B and 4D, when the lift plate 26 rises from the prone position by the rotation of the lift plate 26 in the rising direction as shown by the two-dot line, the rear end of the lift plate 26 When moving forward (to the right in these figures), since the connecting hook 43 is connected to the lift plate connecting portion 41, the connecting members 39 and 40 are also connected to the front of the rear end of the lift plate 26. Move forward in conjunction with movement. Then, as shown in FIG. 1, when the pad 44 provided at the front end of the lift plate 26 comes into contact with the paper feed roller 45, the rotation of the lift plate 26 in the rising direction is stopped. The paper feed roller 45 is rotatably provided on the paper feed device 9 (corresponding to the paper feed device main body of the present invention) in the image forming apparatus main body 1a by a rotation shaft 45a. When the paper 7 is set in the second cassette 15 and is on the lift plate 26, the front end of the paper 7 at the uppermost position contacts the paper feed roller 45, so that the lift plate 26 in the rising direction is lifted. Needless to say, the rotation stops. FIGS. 4A to 4D show only the right connecting member 40.
[0027]
The forward movement of the connecting members 39 and 40 causes the slide plate 30 and the rear end guide 34 to move relative to the cassette body 16 and the cassette extension 17 from the position indicated by the solid line to the position indicated by the two-dot line. Start to move forward. In this way, the rear end guide 34 moves forward in conjunction with the rotation of the lift plate 26 in the rising direction, so that the uppermost sheet 7 among the sheets 7 stored in the second cassette 15 is moved. The front end portion is reliably captured by the paper feeding roller 45 without being shifted backward and displaced, and is fed by the paper feeding roller 45 from the uppermost position of the paper 7 to the secondary transfer unit 8 in order. I have.
[0028]
As shown in FIGS. 2A and 2B, the left connecting member 39 is integrally provided on the left lock lever 18 so as to be relatively slidable in the front-rear direction. In this case, the lock lever 18 moves in the lock operation direction (the left-right direction of the cassette body 16). When the lock lever 18 moves, the connecting member 39 also moves in the same direction integrally with the lock lever 18. become. As described above, the connecting member 39 moves in the sliding operation direction in conjunction with the undulating movement of the lift plate 26. However, when the connecting member 39 moves in the sliding operation direction, the lock lever 18 does not move, and the connecting member 39 does not move. Only comes to move.
[0029]
Further, the right connecting member 40 is also provided on the right lock lever 19 similarly to the case of the left connecting member 39, and the operation of these lock levers 19 and the connecting member 40 are also performed by the left lock lever 18 and the connecting member 39. It operates in the same way as the operation. In this case, the lock operation directions of the right lock lever 19 and the connection member 40 are symmetrical with the lock operation directions of the left lock lever 18 and the connection member 39.
[0030]
Next, the locking operation and the unlocking operation of the cassette body 16 and the cassette extension 17 by the lock levers 18 and 19, and the connecting operation and the releasing operation of the lift plate 26 and the slide plate 30 by the connecting members 39 and 40 will be described.
As shown in FIGS. 3A and 3B, when the second cassette 15 is shortened to the minimum, most of the bottom 17a of the cassette extension 17 and most of the slide plate 30 are connected to the bottom of the cassette body 16. 26 below. At this time, the left locking groove 17f faces the locking protrusion 21 of the left lock lever 18 and the right locking groove 17h faces the locking protrusion 21 of the right lock lever 19. Then, the left lock lever 18 is moved rightward from the unlocked position, the lock projection 21 is fitted into the left lock groove 17f, and the right lock lever 19 is moved leftward. When the locking projection 21 is fitted into the locking groove 17h on the right side, the cassette extension portion 17 is locked with respect to the cassette main body 16, and the shortened state of the second cassette 15 is maintained.
[0031]
When the cassette extension 17 is locked with respect to the cassette body 16 in this manner, the slide plate connecting portion 42 of the left connecting member 39 fits into the groove 38 of the slide plate 30 and the right connecting member 40 Of the slide plate 30 is fitted into the groove 37 of the slide plate 30. Therefore, the left and right connecting members 39 and 40 are connected to the slide plate 30, and as a result, the lift plate 26 and the slide plate 30 are connected via the slide plate 30. Thus, as shown in FIG. 4D, the slide plate 30 can be moved in the front-rear direction in conjunction with the up / down rotation of the lift plate 26 in a state where the second cassette 15 is shortened. Further, in this manner, the locking operation by the lock levers 18 and 19 and the coupling operation by the coupling members 39 and 40 are performed in conjunction with each other.
[0032]
In order to extend the second cassette 15, the left lock lever 18 is moved leftward from the locked state, and the right lock lever 19 is moved rightward. As a result, when the left locking projection 21 is separated from the left locking groove 17f and the right locking projection is separated from the right locking groove 17h, the cassette extension 17 is unlocked with respect to the cassette body 16. Then, the second cassette 15 can be extended.
[0033]
In the state where the left and right lock levers 18 and 19 are moved and the lock projections are separated from the lock grooves, the left and right connecting members 39 and 40 also move integrally with the left and right lock levers 18 and 19. The slide plate connecting portions 42 of the left and right connecting members 39 and 40 are separated from the grooves 38 and 37 of the slide plate 30. Therefore, the slide plate 30 is disconnected from the left and right connection members 39 and 40 and is relatively movable in the front-rear direction with respect to the connection members 39 and 40 and the lift plate 26. In this state, the second cassette 15 is extended by pulling out the cassette extension 17 from the cassette main body 16. Further, in this manner, the unlocking operation by the lock levers 18 and 19 and the unlocking operation by the connecting members 39 and 40 are performed in conjunction with each other.
[0034]
As shown in FIGS. 2A and 2B, when the second cassette 15 is fully extended, most of the bottom 17a of the cassette extension 17 and most of the slide plate 30 are connected to the bottom of the cassette body 16. 26 protrudes. At this time, the left locking groove 17g faces the locking projection 21 of the left lock lever 18, and the right locking groove 17i faces the locking projection 21 of the right lock lever 19. Then, the left locking lever 18 is moved rightward, the locking projection 21 is fitted into the left locking groove 17g, and the right locking lever 19 is moved leftward to lock the locking projection 21. Is fitted into the right locking groove 17i, the cassette extension 17 is locked with respect to the cassette body 16, and the extended state of the second cassette 15 is maintained.
[0035]
When the cassette extension 17 is locked with respect to the cassette body 16, the slide plate connecting portion 42 of the left connecting member 39 fits into the groove of the arm 30 b of the slide plate 30 and the right connecting member 40 The slide plate connecting portion 42 fits into the groove of the arm 30 a of the slide plate 30. Therefore, the left and right connecting members 39 and 40 are connected to the slide plate 30, and as a result, the lift plate 26 and the slide plate 30 are connected via the slide plate 30. Thus, as shown in FIG. 4B, in a state where the second cassette 15 is extended, the slide plate 30 can be moved in the front-rear direction in conjunction with the up / down rotation of the lift plate 26.
[0036]
As shown in FIGS. 2 (a) and 2 (b) and FIGS. 3 (a) and 3 (b), the cassette body 16 has a paper width adjustment for guiding the left and right side edges of the paper 7 in accordance with the width of the paper. A mechanism 57 is provided. The paper width adjusting mechanism 57 includes left and right L-shaped side guides 58 and 59 and a side registration adjusting plate 60.
[0037]
FIG. 5 is a diagram showing a contact state between a pad of a lift plate and a paper feed roller, FIG. 6A is a partially enlarged view of a portion VI in FIG. 5, and FIG. 6B is a pad holder in FIG. 7 (a) is a perspective view of a pad holder supporting a separation pad, FIG. 7 (b) is a perspective view of a pad holder mounting portion in a cassette body, and FIG. 8 (a). FIG. 8B is a perspective view showing a state where the pad holder is attached to the cassette body, and FIG. 8B is a view seen from the direction of arrow VIIIB in FIG. 8A.
[0038]
As shown in FIG. 5 and FIG. 6A, a flat separation pad 47 made of an elastically deformable pad such as a rubber pad rotates the feed roller 45 from the pad 44 of the lift plate 26 which contacts the feed roller 45. It is arranged downstream in the direction. The separation pad 47 is configured to abut on the downstream side in the rotation direction of the paper feed roller 45 from the lowermost point in the drawing of the paper feed roller 45. In this case, the direction of the plane of the separation pad 47 in contact with the sheet feeding roller 45 is set to be the tangential direction at the contact position of the sheet feeding roller 45 in contact with the separation pad 47.
A pad holder 48 is provided on the cassette body 16 so as to be slidable in a direction toward the rotation center of the paper feed roller 45. A separation pad 47 is attached to the bottom surface of a groove 48a formed on the upper surface of the pad holder 48.
[0039]
As shown in FIG. 9 (a), the groove 48a, the bottom is composed of a relatively shallow shallow groove 48a ₁ and the bottom is relatively deep deep groove 48a ₂ Prefecture, directly to the separation pad supporting position of the pad holder 48 Is formed. These shallow groove portions 48a ₁ and the deep groove portion 48a ₂ are both their lateral direction (i.e., the axial direction of the paper feed roller 45) the length of is set larger than the axial length of the feed roller 45. The separation pad 47 is in a state of being supported in the groove 48a, a state in which the bottom portion 47a of the separation pad 47 is floated with respect to the pad holder 48 spaced apart from the bottom surface of the groove 48a opposed to the deep groove portion 48a ₂ . Further, the bottom portion of the separation pad 47 other than the bottom portion 47a of the separation pad 47 is in close contact with the affixed to the bottom surface of the shallow groove portion 48a _1.
[0040]
When the second cassette 15 is mounted on the image forming apparatus main body 1 a, the supply of the center A of the deep bottom groove 48 a _{2 in} the rotation direction of the paper feed roller and the nip portion where the paper feed roller 45 contacts the separation pad 47 is performed. The center B in the paper roller rotation direction is set to be on the straight line in the radial direction of the paper feed roller 45 (that is, the normal line of the paper feed roller 45 passing through the center B of the nip portion) α. Of course, the present invention is not limited to this, and the center A and the center B may not be on the straight line α in the radial direction of the paper feed roller 45.
[0041]
As shown in FIG. 7 (a), on the left side wall 48b of the pad holder 48, a ridge operation guide portion (corresponding to the guide portion of the present invention) 48c and a retaining hook portion adjacent to the operation guide portion 48c. 48d are provided. When the pad holder 48 is attached to the cassette body 16, the operation guide portion 48 c of the protrusion extends in a direction toward the rotation center of the paper feed roller 45. That is, the operation guide portion 48c is disposed on the normal α of the paper feed roller 45 passing through the center B of the nip portion between the separation pad 47 and the paper feed roller 45. The retaining hook portion 48d is provided as close as possible to the operation guide portion 48c. Although not shown in FIG. 7A, an operation guide similar to the left operation guide 48c is provided on the right wall of the pad holder 48 symmetrically with the operation guide 48c.
[0042]
On the other hand, as shown in FIG. 7B, a mounting recess 16e into which the pad holder 48 is inserted and mounted is provided in the pad holder mounting portion of the cassette body 16. A linear guide groove 16g is formed in the right side wall 16f of the mounting recess 16e, and the guide groove 16g extends in a direction toward the rotation center of the paper feed roller 45. The operation guide on the right side of the pad holder 48 is slidably fitted in the guide groove 16g. Also, as shown in FIG. 8B, a linear guide groove 16k is provided on the left side wall 16j of the mounting recess 16e symmetrically with the right side guide groove 16g, similarly to the right side. The left operation guide portion 48c is slidably fitted in the guide groove 16k.
[0043]
In the pad holder 48, the left operation guide portion 48c is fitted into the corresponding guide groove 16k, and the right operation guide portion is fitted into the corresponding guide groove 16g, and these operation guide portions are respectively guided. By being slid while being guided along the grooves 16k and 16g, it is inserted into the mounting recess 16e. Therefore, the pad holder 48 can reciprocate in the sliding direction β toward the rotation center of the sheet feeding roller 45 with respect to the cassette body 16 as shown in FIGS. 6A and 8B.
[0044]
As shown in FIG. 7A, a retaining hook portion 48d is provided on the left side wall 48b of the pad holder 48 adjacent to the operation guide portion 48c. The retaining hook portion 48d is provided at the distal end of an elastic arm portion 48e extending in parallel with the operation guide portion 48c on the left side wall 48b of the pad holder 48. Retaining hook portion 48d has a guide taper section 48d ₁ in its front end side and the guide tapered portion 48d engaging portion 48d ₂ that are formed continuously in _one. In that case, the engaging portion 48d ₂ is substantially perpendicular to the resilient arm 48e, the engaging portions 48d ₂ is protruded to the left of the left side wall in the same direction are provided. Although not shown in FIG. 7A, a retaining hook and an elastic arm similar to the left retaining hook 48d and the elastic arm 48e are provided on the right side wall of the pad holder 48 symmetrically with them. Have been.
[0045]
On the other hand, a retaining hook engaging portion 16h is formed on the right side wall 16f of the mounting concave portion 16e so as to be adjacent to the guide groove 16g. The retaining hook engaging portion 16h has a right retaining hook portion. Are engageable. Further, a disengagement concave portion 16i is provided on the right side wall 16f of the mounting concave portion 16e above the retaining hook engaging portion 16h. When the pad holder 48 is attached to the attachment recess 16e, the engagement releasing recess 16i is configured such that the elastic arm on the right side of the pad holder 48 is opposed. As shown in FIG. 8 (b), also the left side wall 16j of the mounting recessed portions 16e, similarly to the right, the left stopper engaging portion 48d ₂ are engageable retaining hook engaging portion of the hook portion 48d 16m and a disengagement concave portion 16n facing the left elastic arm portion 48e are provided symmetrically with those on the right side. The left and right retaining hooks and the left and right retaining hook engaging portions 16m and 16h constitute the engaging means of the present invention, and the left and right retaining hooks constitute the engaging portion of the present invention. ing. Note that these engaging means and engaging portions need not necessarily be provided on the left and right side walls of the pad holder 48, and may be provided on at least one of the left and right side walls of the pad holder 48.
[0046]
Further, as shown in FIGS. 6A and 6B, when the pad holder 48 is attached to the attachment recess 16 e, a compression spring (a book spring) that constantly urges the pad holder 48 toward the paper feed roller 45. A biasing means 49 is contracted between the pad holder 48 and the cassette body 16. The compression spring 49 is held in a spring guide 48f extending in the pad holder 48 in parallel with the guide portion 48c. Therefore, the compression spring 49 urges the pad holder 48 in the same urging direction γ as the sliding direction β of the pad holder 48.
[0047]
The pad holder 48 is inserted into the mounting recess 16e from above with the separation pad 47 facing upward and the compression spring 49 held in the spring guide 48f. At this time, the left operation guide portion 48c is fitted into the left guide groove 16k, and the right operation guide portion is fitted into the right guide groove 16g, and these operation guide portions are guided into the corresponding guide grooves 16g. The pad holder 48 is inserted into the mounting recess 16e while the compression spring 49 is compressed.
[0048]
When the pad holder 48 is inserted a predetermined amount into the mounting recess 16e, the right stopper hook portion with the guide tapered portion 48d ₁ of the left stopper hook portion 48d comes into contact with the retaining hook engaging portions 16m guide The tapered portion contacts the retaining hook engaging portion 16h. Thereafter, when the pad holder 48 is further inserted into the mounting recess 16e, the left and right elastic arms are bent inward by the left and right guide taper portions. When the left and right retaining hook portions pass through the retaining hook engaging portions 16m and 16h, respectively, the bent left and right elastic arms return to their original positions by their elastic restoring force. Thereby, the locking portions of the left and right retaining hook portions can be engaged with the retaining hook engaging portions 16m and 16h, respectively.
[0049]
Finally, when the hand is released from the pad holder 48, the pad holder 48 is slightly moved upward by the spring force of the compression spring 49, and the locking portions of the left and right retaining hooks are respectively moved as shown in FIG. the retaining hook engaging portions 16m, engage in 16h (figure only the state which the locking portion 48d ₂ of the left side of the retaining hook 48d is engaged with the retaining hook engaging portions 16m are shown ), Further upward movement of the pad holder 48 is prevented. That is, the pad holder 48 is prevented from falling out of the mounting recess 16e. Thus, the pad holder 48 is fitted and mounted in the mounting recess 16e.
[0050]
To remove the pad holder 48 attached to the attachment recess 16e, a finger is inserted into the left and right engagement release recesses 16n and 16i, and the left and right elastic arms are pressed inward. Then, the left and right elastic arms are bent inward, respectively, and the left and right locking portions are disengaged from the corresponding retaining hook engaging portions 16m and 16h, respectively, and the pad holder 48 is moved upward by the spring force of the compression spring 49. . Thereby, the pad holder 48 is easily removed from the mounting recess 16e.
[0051]
When the second cassette 15 in which the pad holder 48 is mounted on the mounting recess 16e is mounted on the image forming apparatus main body 1a, the separation pad 47 of the pad holder 48 comes into contact with the outer peripheral surface of the paper feed roller 45, and The paper feed roller 45 presses the pad holder 48 against the spring force of the compression spring 49. Therefore, when the second cassette 15 is mounted on the image forming apparatus main body 1a, the pad holder 48 presses the paper feed roller 45 toward the rotation center thereof by the spring force of the compression spring 49. Thus, the separation pad 47 as shown in FIG. 9 (a) to press the contact with the paper feed roller 45 to the outer peripheral surface of the paper feed roller 45, the separation pad 47 to flex in the deep groove 48a in the ₂ Become.
[0052]
The sheet feeder of this first example configured as described above, the separation pad 47, the portion which is the contact nip between the opposing vital feed roller 45 to the deep groove portion 48a _2, deep groove 48a _2, the separation pad 47 made of an elastic material such as rubber is formed by the frictional resistance between the paper 7 and the separation pad 47 when the paper 7 is fed by the rotation of the paper feed roller 45 because the separation pad 47 is not attached to the bottom surface of the paper 2. Even if the separation pad 47 is distorted while being restrained, the portion of the separation pad 47 to which the separation pad 47 is not attached is freely elastically expanded and deformed. Thereby, the restrictive distortion of the separation pad 47 is suppressed. Therefore, the minute vibration due to the distortion of the separation pad 47, which is likely to occur when the entire bottom surface of the separation pad 47 is attached to the bottom surface of the groove 48a, is suppressed, and the generation of the sound due to the minute vibration is prevented. In particular, when the recording medium fed by the paper feed roller 45 is an OHP sheet, the frictional resistance between the OHP sheet and the separation pad 47 is large, so that the restrictive distortion of the separation pad 47 is more effectively suppressed. As a result, the occurrence of minute vibrations and sound due to the minute vibrations is more reliably prevented. Moreover, the depth since the bottom surface of the separation pad 47 other than the bottom surface of the bottom groove 48a ₂ opposed to the separation pad 47 is attached to the bottom surface of the shallow groove portion 48a _1, the entire bottom surface of the separation pad 47 is shallow groove 48a ₁ The separation pad 47 does not move relative to the pad holder 48 when the paper 7 is fed by the rotation of the paper feed roller 45 as compared with the case where the separation pad 47 is not attached to the bottom surface. Therefore, the paper 7 can be reliably and stably fed.
[0053]
Moreover, deep grooves 48a ₂ can be formed with shallow grooves 48a ₁ during molding of the pad holder 48, moreover, the separation pad 47 is not necessary to process the cut of a number, such as described above in the prior art Therefore, both the separation pad 47 and the pad holder 48 can be easily manufactured.
[0054]
Further, a retaining hook portion 48d provided on a left side wall 48b of the pad holder 48 is engaged with a retaining hook engaging portion 16m of the cassette body 16, and a retaining hook portion provided on a right side wall is a cassette body. The pad holder 48 is detachably attached to the cassette main body 16 by engaging with the retaining hook engagement portions 16h of the 16. Accordingly, even if the pad holder 48 tries to rotate along with the cassette body 16 by the play of the paper feed roller 45, the retaining hook portions are provided on the left and right side walls of the pad holder 48. The retaining hook is hard to come off from the cassette body 16. Therefore, the separation pad 47 can be stably supported.
Further, since the pad holder 48 is slidably attached to the cassette body 16, the attachment of the pad holder 48 to the cassette body 16 is simplified.
[0055]
Further, since the pad holder 48 slides toward the rotation center of the paper feed roller 45, the separation pad 47 supported by the pad holder 48 is stabilized in the radial direction (normal direction) of the paper feed roller 45. To come into contact. Therefore, the paper 7 can be stably separated by the separation pad 47, and the paper 7 can be reliably fed by the paper feed roller 45 for each sheet.
Further, since the retaining hooks protruding in the left-right direction of the pad holder 48 engage with the cassette main body 16, even if the pad holder 48 tries to rotate with the rotation of the paper feed roller 45, the pad holder 48 and the cassette main body 16 are not connected. Is more difficult to disengage. Therefore, the separation pad 47 can be more stably and more reliably supported.
[0056]
Further, an operation guide portion is provided on the left and right side walls of the pad holder 48. The operation guide guides the pad holder 48 in the sliding direction, so that the pad holder 48 can be slid more stably and the pad holder 48 can be slid more stably. 48 can be suppressed more effectively.
[0057]
Further, the pad holder 48 is constantly urged in the sliding direction by the compression spring 49, so that the separation pad 47 comes into contact with the outer peripheral surface of the sheet feeding roller 45. Thus, the spring force of the compression spring can be used efficiently.
[0058]
FIG. 9B is a partially enlarged view similar to FIG. 9A, showing a second example of the embodiment of the sheet feeding device of the present invention. In the following description of each example of the embodiment of the present invention, the same reference numerals are given to the same components as those described before the example, and the detailed description thereof will be omitted.
[0059]
In the first example the second cassette 15 described above, although the groove 48a of the pad holder 48 the separating pad 47 is supported is formed of a shallow groove portion 48a ₁ and the deep groove portion 48a ₂ Prefecture, the second example In the second cassette 15, as shown in FIG. 9B, the groove portion 48a is a deep groove having a deep bottom groove. The depth of the second example of the groove 48a is set the same or almost the same as the depth depth of the bottom groove 48a ₂ of the first example.
[0060]
A flat spacer 50 is attached to the bottom surface of the groove 48a of the second example. The thickness of the spacer 50 is the same or is set to be substantially the same as the difference between the deep groove 48a ₂ and shallow groove portions 48a ₁ of the depth of the first example. Further, the spacer 50 has an opening 50a is formed, the peripheral shape of the opening 50a is the same or is set to be substantially the same as the first example of the deep groove portion 48a ₂ of the peripheral shape. Therefore, when the separation pad 47 is supported by the groove 48a, the portion 47b of the separation pad 47 facing the opening 50a is separated from the bottom of the groove 48a and floats on the pad holder 48. By thus opening 50a constitutes a deep groove 48a ₂ of the first example described above, so that the same effects as deep groove 48a ₂ of the effects of the first example is obtained.
Other configurations and other operational effects of the second cassette 15 of the second example are all the same as those of the above-described second cassette 15 of the first example.
[0061]
In the above-described example, the paper feeding device of the present invention is applied to a paper feeding device using a telescopic cassette. It can also be applied to devices. Further, the sheet feeding device of the present invention can be applied to a conventional general sheet feeding device not using a sheet feeding cassette. In this case, the paper feeding device main body of the present invention corresponds to only the paper feeding device portion of the image forming apparatus main body.
Further, in the above-described example, the paper feeding device that feeds the recording medium 7 such as paper to the transfer unit 8 has been described, but the paper feeding device that feeds an original such as paper on which an image is recorded to the image reading unit is described. It can also be applied to devices.
[Brief description of the drawings]
FIG. 1 is a diagram schematically illustrating an image forming apparatus using a first example of a sheet feeding device according to an embodiment of the present invention.
FIGS. 2A and 2B show the cassette in an extended state, wherein FIG. 2A is a top view and FIG. 2B is a bottom view.
3A and 3B show a cassette in a shortened state, wherein FIG. 3A is a top view and FIG. 3B is a bottom view.
FIGS. 4A and 4B illustrate connection and interlocking operation between a lift plate and a slide plate, FIG. 4A illustrates connection in an extended state, FIG. 4B illustrates interlocking operation in an extended state, and FIG. () Is a diagram illustrating the connection in the shortened state, and (d) is a diagram illustrating the interlocking operation in the shortened state.
FIG. 5 is a diagram illustrating a contact state between a pad of a lift plate and a paper feed roller.
6A is a partially enlarged view of a portion VI in FIG. 5, and FIG. 6B is a view showing a state where a cross section of the pad holder is taken in FIG.
FIG. 7A is a perspective view of a pad holder supporting a separation pad, and FIG. 7B is a perspective view of a pad holder mounting portion of the cassette body.
8A is a perspective view showing a state in which a pad holder is attached to a cassette main body, and FIG. 8B is a view seen from the direction of arrow VIIIB in FIG. 8A.
9A is a partially enlarged view of a contact portion between a separation pad and a paper feed roller in a first example, and FIG. 9B is a view similar to FIG. 9A showing a second example of the embodiment of the present invention; FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 1a ... Image forming apparatus main body, 1b ... Inner wall surface, 1c ... Cassette insertion / extraction opening, 2 ... Exposure unit, 3 ... Developing unit, 4 ... Image carrier, 5 ... Intermediate transfer medium, 6 ... Primary Transfer unit, 7: Recording medium (paper), 8: Secondary transfer unit, 9: Paper feeder, 10: Fixing unit, 11: Discharge tray, 12: First transport path, 13: Second transport path, 14 ... First cassette, 15 ... Second cassette, 16 ... Cassette body, 16e ... Mounting recess, 16g, 16k ... Guide groove, 16m, 16h ... Retaining hook engaging part, 17 ... Cassette extension part, 26 ... Lift plate , 44 pad, 45 feed roller, 47 separation pad, 48 pad holder, 48 a groove, 48 a ₁ shallow groove, 48 a ₂ deep groove, 48 c operation guide, 48 d retaining hook part, 48d ... locking portion, 48e ... elastic arm, 49 ... compression spring, 50 ... spacer, 50a ... opening, 57 ... paper width adjusting mechanism

Claims (3)

A paper feed roller rotatably provided in the paper feeder main body, a pad holder slidably provided in the paper feeder main body and supporting a separation pad abutting on the paper feed roller; And a biasing means for biasing the separation pad against the paper feed roller by biasing the paper roller toward the paper feed roller.
At the separation pad support position of the pad holder, a groove portion is formed at a position of the pad holder corresponding to a nip portion where the paper feed roller and the separation pad abut,
Of the bottom surface of the separation pad, a bottom surface portion facing the groove is not in close contact with the pad holder, and a bottom surface portion of the bottom surface of the separation pad other than the bottom portion facing the groove is in close contact with the pad holder. A sheet feeding device. The paper feeding device according to claim 1, wherein the groove is provided directly on the pad holder. The sheet feeding device according to claim 1, wherein a spacer member having an opening is provided at the separation pad supporting position of the pad holder, and the groove is formed by the opening of the spacer member.

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