JPH06239483A - Paper feeder for image forming device - Google Patents

Abstract

PURPOSE:To enable the display of constant sheet separating performance to both OHP sheets and ordinary sheets by the surface shape of a pad member in a sheet separating device formed of the combination of a retarding member and a feed roller. CONSTITUTION:A pad member 2p disposed at a retarding member is formed by combining protrusions 22 of width D with recessed grooves 23 of width C, and the protrusions 22 are disposed being inclined by an angle theta in relation to the conveyed direction of sheets. The protrusions 22 are formed in the state of the recessed grooves 23 being cut in by the specified depth H from the surface of a plate member formed of silicone rubber or the like, and it is so formed that a friction coefficient to OHP sheets and a friction coefficient to ordinary sheets can be maintained to the constant value over a long period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet separating device used in a sheet feeding device of an image forming apparatus, and more particularly, a pad member provided on a retard member arranged to face a sheet feeding roller is provided to a flat plate member. The present invention relates to a sheet feeding device of an image forming apparatus, which forms unevenness to form a concavo-convex shape and can perform a separating action on both special sheets such as an OHP sheet and ordinary sheets in a good state.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine or a printer, a sheet containing member such as a plurality of sheet feeding trays is arranged in a sheet feeding section, and sheets of different sizes are accommodated in these sheet feeding trays. In addition, a means is provided for feeding out a sheet of a size suitable for the size of the original document, the reduction ratio, and the like. In addition to the above-mentioned paper feed tray and the like, a manual feed tray is provided so that special size paper such as paper that cannot be fed from the paper feed tray, thick paper such as postcards, special sheets such as OHP sheets, etc. It is designed so that it can be fed. In the paper feed unit from the manual feed tray, in order to feed postcards, OHP sheets, and the like in addition to plain paper and the like, a paper feed device configured by combining a paper feed roller and a retard member is used. .

An example of a paper feeding device constructed by combining the paper feeding roller and a retard member is described in, for example, Japanese Patent Laid-Open No. 2-28.
As disclosed in Japanese Laid-Open Patent Publication No. 437, for example, the pad member of the retard member is pressed to the downstream side in the paper transport direction with respect to the paper feed roller pressed against the paper feed side end of the tray, and the paper sorting device is operated. I am configuring. As a mechanism for arranging a pad member opposed to the paper feeding roller and performing a paper separating action, for example, as shown in Japanese Patent Laid-Open No. 2-110040, the pad member is made of urethane rubber or the like. Is being used. In general pad members, a rubber material is used as a base, and a material in which powder of a cork material is mixed with the rubber, a material in which a fibrous material is mixed, or the like is used. As the rubber to be used, silicone rubber or urethane rubber can be used.

Further, as shown in the above-mentioned conventional example, by applying a lubricant to the pad member, the friction coefficient is reduced, and a means for exhibiting a good separating action in the sheet separating device is used. There is. Further, it is possible to prevent misfeeding even for sheets such as an OHP sheet having a property of closely adhering between sheets, and to exhibit a good separating action.

[0005]

However, as shown in the above-mentioned conventional example, even when the friction coefficient is changed by using a means such as applying a lubricant to the pad member, the pad member is not used during use. There is a problem that the judgment force changes with the passage of time. In addition, in a paper separating device that combines a general flat plate-like pad member and a paper feeding roller,
As shown in the graph, the vertical axis represents the coefficient of friction and the horizontal axis represents the number of running vehicles.
A very large coefficient of friction is exerted on the sheet in the initial stage, and thereafter, a large amount of sfeed is generated, which causes a state in which the sheet cannot be actually fed. Also, for plain paper,
As indicated by the curve a-3, although a predetermined coefficient of friction can be obtained in the initial stage, there is a problem that the coefficient of waiting on the surface of the pad member gradually decreases due to changes over time, and double feeding is likely to occur. .

Therefore, in order to minimize the occurrence of misfeed at the initial stage of using the pad member as shown in the graph of FIG.
One of the methods is to use the means as disclosed in Japanese Patent Publication No. 0. However, as described above, even if a means for adjusting the distribution of the friction coefficient in the width direction of the pad member and appropriately adjusting the initial separating force is used, in response to the change in the friction coefficient due to aging, Since it is necessary to perform extra adjustment work such as adjusting the pressing force of the retard member at any time, this also causes a difficulty in maintenance.

In order to solve the above-mentioned problems, for example, as shown in Japanese Patent Laid-Open No. 138039/1990, a fibrous material is mixed with rubber constituting a paper feed roller to obtain a friction coefficient. It is also conceivable to apply a technique for preventing the change in the pad member. In addition, JP-A-57
As disclosed in JP-A-203625 and JP-A-64-34825, it may be considered to apply a technique of forming irregularities on the surface of a roller to a pad member. However, in each of the above-mentioned conventional examples, since the pad member is formed of a flat plate-like member, there remains a problem that the effect cannot be confirmed even if the roller member has a special surface shape. Further, various types of providing unevenness on the surface of the sheet feeding roller have been proposed, as disclosed in Japanese Utility Model Laid-Open No. 52-39140 and Japanese Patent Laid-Open No. 62-65859. However, in any case, there remains a problem that it is difficult to apply the pad member easily.

[0008]

It is an object of the present invention to solve the above-mentioned problems of the conventional paper separating apparatus, and to provide the surface of the pad member with streaky irregularities inclined at a predetermined angle with respect to the paper conveying direction. It is an object of the present invention to provide a pad member that can exhibit a good separating effect on an OHP sheet and that does not change its separating performance even with time.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a paper feed roller and a retard member are disposed on the paper feeding side of a member such as a paper feed tray on which paper is placed so as to face each other. The present invention relates to a sheet feeding device that separates sheets fed by a paper roller using a retard member and feeds the sheets one by one. In the present invention, the surface of the pad member of the retard member arranged to face the paper feed roller is in contact with the paper,
It is configured to be inclined at a predetermined angle with respect to the sheet transport direction and to be formed by combining a ridge and a groove. Further, in the pad member of the present invention, the protrusion and the concave groove have an inclination angle of 0 to 60 ° with respect to the sheet conveyance direction and a width of 0.5.
The depth of the groove can be set to ˜8 mm and the depth of the groove can be set to 0.5 to 5 mm from the surface of the ridge. In addition to the above configuration, in the present invention, it is also possible to form the pad member with a flat plate-like member and form the recesses in a pattern of the same shape. Furthermore, in the present invention, the pad member is made of silicon. It can also be made of rubber.

As described above, when the surface of the pad member is formed by the ridges and grooves, when it is desired to change the friction coefficient with respect to the OHP sheet, the surface shape of the pad member can be changed. As a result, the retard member can be easily designed. In addition, it is possible to easily set the judgment action of the pad member, and it is possible to prevent the occurrence of misfeed and double feed. In addition, the friction coefficient of the pad member is less likely to be affected by changes over time, and a stable separating action can be exerted for a long period of time.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sheet feeding device of an image forming apparatus according to the present invention will be described with reference to the illustrated example. The example shown in FIG. 1 shows an example of the sheet feeding device 5 arranged on the tray 1. The sheet feeding device 5 includes a sheet feeding roller 6 provided on a drive shaft 7.
And a retard member 10 are combined to constitute a paper separating mechanism. The retard member 10 used in the paper feeding device 5 of FIG. 1 supports the pad member 11 pressed by the paper feeding roller 6 via the holder 12, and supports the holder 12 with respect to the base member 14. By using a pressing means (not shown), a predetermined pressing force can be exerted between the paper feed roller and the pad member.

In the sheet feeding device constructed as described above, the pad member provided on the retard member is constructed as shown in FIG. Like the pad member 11 of FIG. 1, the pad member 20 shown in FIG. 2 is fixed to the holder 12 using an adhesive means such as a double-sided tape, and is formed in a flat plate shape using rubber or the like. ing. In the pad member 20, a ridge 22 and a groove 23 are formed on the surface of a plate-shaped member configured as the base member 21.
And are arranged. The ridges 22 formed on the pad member 20 have an inclination angle of 0 to 60 ° with respect to the sheet conveying direction, a width D of 0.5 to 8 mm, and a depth from the surface of the ridge of the concave groove. The height H is set to 0.5 to 5 mm, and the groove 23
The width C is also the same as the width of the ridge.

In the example of the pad member 20a shown in FIG. 3, the protrusion and the groove are formed on the upper surface of the base member 21 as in the case of FIG. 2, but the side members 24 protrude on both sides thereof. The units are arranged in the sheet conveying direction to provide a means for eliminating the catch of the sheet at the time of feeding. And
The pad members 20 and 20 shown in FIGS.
In a, a groove 2 is provided for a plate member made of rubber or the like.
By integrally forming 3 in a state in which it is dug by a depth H from a flat plate-shaped main body, it is possible to use means for forming the contact surface of the paper by projecting the ridge 22 in a streak shape.

Further, in the pad member of the present invention, as shown in FIG. 4, the base member 25 and the protruding portion 26 arranged on the upper portion are made of different materials, and the pad member 20 is formed.
b can be configured. By using different materials, not only the hardness of the pad member can be changed, but also the material can be changed according to the cost and function. In the example shown in FIG. 4, the pad member 20b is formed by linearly adhering the rubber material of the ridges 26 made of a harder material to the base member 25 made of a relatively soft material. Is used. The protrusion height H of the ridge 22, the width between the ridge and the groove, and the inclination angle θ1 of the ridge with respect to the sheet conveying direction should be the same as those in FIGS. Is possible.

In the pad member 20c of the present invention constructed as described above, the widths of the protrusions 22c and the concave grooves 23c,
As shown in FIG. 5, the relationship between the slopes is as shown in FIG.
And the width C of the groove are 2.5 mm, and the inclination angle θ
1 can be set to 45 °. When the pad member 20c is configured as shown in FIG.
Although the coefficient of friction with respect to the sheet is set to be small, the life of the pad member can be extended. Further, in the example of the pad member 20d shown in FIG. 6, the width D of the protrusion 22d is set to 2.5 mm, the width C of the concave groove 23d is set to 1 mm, and the inclination angle θ1 is the same as in the case of FIG. I am configuring. When the pad member 20d is configured as shown in FIG. 6, the friction coefficient with respect to the OHP sheet tends to be slightly larger than that in the case of FIG.

In the case of the pad member 20e shown in FIG. 7, the widths C and D of the ridge 22e and the groove 23e are 5 respectively.
mm, and the inclination angle θ1 with respect to the paper transport direction is
The setting is made in the same manner as the above two examples. In the example shown in FIG. 7, the friction coefficient with respect to the OHP sheet tends to be larger than that in the case of FIG. On the other hand, in the example of the pad member 20f shown in FIG. 8, the width D of the protrusion 22f and the width C of the concave groove 23f are set to 2.5 mm, respectively, and the protrusion 22f is conveyed in the sheet conveying direction. The inclination angle θ2 with respect to is set to 22.5 °. Then, in FIG.
As shown in (1), when the ridges are arranged, the friction coefficient with respect to the OHP sheet appears to be relatively large, but the life of the pad member tends to be shortened.

As described above, in addition to arranging the ridges at a predetermined angle, the pad member 20g shown in FIG.
As described above, the ridge 22g and the concave groove 23g are arranged in parallel to the sheet conveying direction, and the width D of the ridge 22g and the concave groove 23g are arranged.
The width C of g and 2.5 mm are formed. However, when the ridges are formed parallel to the sheet conveying direction as in the pad member 20g of FIG.
Besides increasing the friction coefficient for the HP sheet,
There was a trend towards shorter life.

By the way, in the sheet feeding section from the tray, the contact section between the sheet feeding roller and the pad member is shown in FIGS.
As shown in FIG. 5, the paper feed roller 6 is in contact with only a part of the pad member 30 and is in a state of exhibiting a separating action on the paper. As shown in FIG. 10, the ridge 32 and the concave groove 3 are formed in the roller pressing portion 36 with which the sheet feeding roller 6 abuts.
3 is provided, the surface of the paper feed roller exerts a function of pressing the paper against the ridge 32. Then, in consideration of the friction coefficient between the paper feed roller and the paper, the friction between the surface of the pad member and the paper, and the friction between the papers, the separating action on the paper and the feeding of the paper are performed. The action is exerted. As shown in FIG. 11, in the roller pressing portion 36, the width and inclination angle of the ridges are important factors for the separating action. Further, since the front and rear portions 35 and 37 of the roller pressing portion 36 are configured as portions that press the sheet against the pad member and exert a frictional action, the front side portion 35 and the upstream side portion 37 are ,
The shape and the like of the ridge can be arbitrarily set.

Therefore, in the pad member of the present invention, as shown in FIG.
It is considered that, as shown in FIG. 14 to FIG. 14, the shape of the roller pressing portion 36 can be specified and the shapes of other portions can be set arbitrarily. For example, in the example of the pad member 30a shown in FIG. 12, the ridge 32a is set to a predetermined inclination angle only in the roller pressing portion 36, and the streak-like ridges and the concave grooves 33a are alternately arranged. However, as shown in FIG. 9, the front side portion and the upstream side portion are provided with ridges and concave grooves that are parallel to the sheet conveying direction. Further, in the pad member 30a, the front side portion and the upstream side portion are configured such that the friction coefficient of the pad member with respect to the paper is large, so that a good result can be given to the separating action.

Also, the pad member 30b shown in FIG.
In the example, the protrusions 32b and the concave grooves 33b are alternately formed in a streak pattern only on the roller pressing portion 36, and the front side portion 3
5 and the upstream side portion 37 form a flat sheet contact surface having the same height as the protrusion. That is, in FIG.
In this case, only the roller pressing portion 36 is provided with a means for forming a groove in a state where the concave groove 33b having a predetermined depth is dug, so that the friction coefficient for the paper has a predetermined value. . Further, in the example shown in FIG. 14, the roller pressing portion 36 is attached to the main body of the pad member 30c formed in a planar shape.
The semicircular concave portion 33c is provided only in the portion of
c is formed on the same plane as the planes of the front and rear portions 35 and 37. Then, as shown in FIGS. 13 and 14, respectively, only in the portion of the roller pressing portion with which the sheet feeding roller abuts,
By processing the surface of the pad member to form the uneven portion, the coefficient of friction with respect to the paper can be set to a predetermined value, and the separating action can be satisfactorily exhibited.

In addition to each of the above-mentioned embodiments, in the present invention,
As shown in FIGS. 15 to 17, the surface shape of the pad member can be set. In the example shown in FIG. 15, the diamond-shaped recess 42 is dug from the surface of the pad member 40 to form irregularities, and the surface portion of the pad member is formed as the protrusion 41 on the surface of the same height. And
In the state where the paper is pressed against the surface of the pad member 40, the friction coefficient and the friction area are set according to the shape of the recess, and the separating action on the paper can be exhibited.

Also, the pad member 40a shown in FIG.
In the above example, the concave portion 42a is formed in a substantially elliptical shape, and the major axis of the elliptical shape is set in the sheet conveyance direction. further,
In the example of the pad member 40b shown in FIG.
b is formed in a substantially triangular shape, and one surface of the triangular shape is arranged at a right angle to the sheet conveying direction. In each of FIG. 16 and FIG. 17, the protrusion 41 is
By forming each of a and 41b in a planar shape, they are used as a friction surface with the sheet and perform a separating action on the sheet with the sheet feeding roller.

As described above, the surface of the pad member is formed as a flat surface having a predetermined pattern, and a mechanism for imparting a separating action is configured in a state where the paper feed roller presses the paper against the surface of the pad member. In this case, as shown in the graph of FIG. 18, the friction coefficient between the paper and the OHP sheet can be obtained. In the example shown in the graph of FIG. 18, the curve a-1 and the curve a-3 indicate the friction coefficient between the OHP sheet and the plain paper in the conventional pad member. The above graph shows data when the pad member is made of silicone rubber.
Since the initial coefficient of friction of the sheet is very large, there is a drawback that misfeeds and the like are extremely increased when the OHP sheet is fed. Also, with respect to plain paper, when the number of running sheets increases, the friction coefficient gradually decreases, which causes a problem that the sorting performance cannot be improved.

On the other hand, in the pad member of the present invention,
It was found that the state of the change in the friction coefficient of the pad member with time can be obtained as indicated by the friction coefficient curve a-2 for the OHP sheet and the friction coefficient curve a-4 for the plain paper. Therefore, in the pad member of the present invention, by appropriately setting the surface shape, even if the number of traveling sheets increases, the judgment performance of the pad member is not significantly changed, and the OHP sheet and the plain paper are not changed. Even so, it is possible to exhibit a certain judgment performance. Then, as shown in the graph of FIG. 18, by using any one of the pad members of the present invention, it is possible to save the trouble of adjusting the paper feeding device and to provide the paper feeding device with a constant handling force. It can be used as a device having.

Aside from the example of the paper separating apparatus having the general structure shown in FIG. 18, when the constituent materials of the pad member of the present invention are limited, as shown in the graphs of FIGS. 19 to 24, respectively. , In comparison with the conventional pad member,
It is possible to obtain the separation performance for the OHP sheet and the plain paper. In each graph to be described later, the vertical axis represents the coefficient of friction and the horizontal axis represents the number of running sheets. As in the case of the graph in FIG. 18, the pad member is compared with the degree to which the number of fed sheets increases. Shows the state of change of the friction coefficient at.

The graphs shown in FIGS. 19 and 20 are:
FIG. 19 shows a case where the pad member is made of a material in which fibers are mixed with nitrile or butylene rubber, and the graph of FIG. 19 is such that the friction surface is made of an uneven member as in the embodiment of the present invention. The graph of FIG. 20 shows the case where the conventional friction surface is flat. As shown in FIG. 20, in the case where the friction surface of the conventional pad member is set to have a planar shape, there is a tendency that the coefficient of friction of the plain paper gradually decreases as the number of running sheets increases. Further, with respect to the OHP sheet, the friction coefficient greatly changes as the number of running sheets increases, and it is difficult to keep the sorting performance constant. On the other hand, when the surface shape of the pad member of the present invention is configured by combining uneven patterns, the friction coefficient is set to a constant value for both the OHP sheet and the plain paper. It has been shown that it can be maintained and can be used for a long period of time in a state in which the judgment performance does not change with time.

The graphs shown in FIGS. 21 and 22 are:
The case where the pad member is made of a urethane-based material is shown. As can be seen from the graph of FIG. 22, in the case of the conventional flat plate-shaped pad member, the number of running sheets increases, whereas in the OHP sheet, the coefficient of friction increases as the number of running sheets increases. It is in a fluctuating state, it is difficult to maintain the sorting performance constant, and the plain paper tends to have a gradually decreasing friction coefficient. On the other hand, as shown in the graph of FIG. 21, in the case of using a pad member of the present invention having a surface on which a paper slides by combining uneven patterns, an OHP sheet is usually used. The coefficient of friction can be maintained at a constant value for both paper and paper, and it can be used for a long period of time while the separation performance does not change with time.

Further, the graphs shown in FIGS. 23 and 24 show the case where the pad member is made of a silicon rubber material. As can be seen in the graph of FIG. 24,
In the case of the conventional flat plate-shaped pad member, the number of running sheets increases, whereas in the OHP sheet, the friction coefficient greatly decreases as the number of running sheets increases, and double feeding easily occurs. Has become. Therefore, if a certain number of sheets or more are fed, the normal feeding operation cannot be performed unless the pad member is replaced. Further, in plain paper, the friction coefficient tends to gradually decrease.
On the other hand, as shown in the graph of FIG. 23, in the case of using a pad member of the present invention in which a surface on which a sheet slides is formed by combining uneven patterns, OH
The friction coefficient can be maintained at a constant value for both the P sheet and the plain paper, and it can be used for a long period of time while the separation performance does not change with time.

In the pad member of the present invention, as shown in each of the above-mentioned embodiments, the ridges are arranged at a predetermined angle with respect to the sheet conveying direction, or an arbitrary pattern is formed. Thus, means for forming the recess can be used. And, in particular, as shown in FIG. 5, forming projecting lines in an oblique streak shape, and as shown in FIGS.
Arrangement of locally inclined ridges, or Figure 1
As described in Nos. 4 to 17, by forming a concave portion or the like, the paper separating performance can be exhibited in a good state. Further, as the paper feed roller arranged so as to face the pad member, similar to the conventional roller member, a member made of silicon rubber or the like can be used, and a rubber mixed with fibers can be used. Is. Therefore, it is possible to configure a combination mechanism of the pad member and the paper feed roller according to the property of the paper used in the image forming apparatus.

[0030]

Since the sheet feeding device of the image forming apparatus of the present invention has the above-mentioned structure, the pad member is formed by combining the surface of the pad member with the ridges and the grooves. It is possible to simplify the configuration of the members and the configuration of the sheet feeding device. When it is desired to change the friction coefficient with respect to the OHP sheet, it can be dealt with by changing the surface shape of the pad member, and the retard member can be easily designed. In addition, it is possible to easily set the judgment action of the pad member, and it is possible to prevent the occurrence of misfeed and double feed. Furthermore, with the pad member of the present invention, the effect of aging on the friction coefficient for papers is less likely to occur, and a stable separating action can be exerted for a long period of time, and the labor of maintenance for the retard member can be omitted. It is possible.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration of a retard member of the present invention.

FIG. 2 is a perspective view showing a configuration of a pad member of the present invention.

FIG. 3 is a perspective view of a second embodiment of the pad member.

FIG. 4 is a perspective view of a third embodiment of the pad member.

FIG. 5 is a plan view of an example of a combination of a protrusion and a groove.

FIG. 6 is a plan view of a second embodiment showing the configuration of the pattern of the pad member.

FIG. 7 is a plan view of a third embodiment of the pad member.

FIG. 8 is a plan view of a fourth embodiment of the pad member.

FIG. 9 is a plan view of a fifth embodiment of the pad member.

FIG. 10 is a side view of a retard member that combines a pad member and a paper feed roller.

11 is an explanatory diagram showing the configuration of the pad member of FIG.

FIG. 12 is a first plan view of an example of identifying a pattern on a front side portion.

FIG. 13 is a second plan view of an example of identifying a pattern on the front side portion.

FIG. 14 is a third plan view of the example for identifying the pattern on the front side portion.

FIG. 15 is a plan view of a first example in which a uniform pattern is formed on the surface of the pad member.

FIG. 16 is a plan view of a second example in which a uniform pattern is formed on the surface of the pad member.

FIG. 17 is a plan view of a third example in which a uniform pattern is formed on the surface of the pad member.

FIG. 18 is a graph showing the relationship between the friction coefficient of a general pad member and the number of running sheets.

FIG. 19 is a graph showing the relationship between the friction coefficient and the number of running sheets in the nitrile / butylene rubber-based pad member of the present invention.

FIG. 20 is a graph showing the relationship between the friction coefficient and the number of running sheets in a conventional nitrile or butylene rubber pad member.

FIG. 21 is a graph showing the relationship between the friction coefficient and the number of running sheets in the urethane-based pad member of the present invention.

FIG. 22 is a graph showing the relationship between the friction coefficient and the number of running sheets in a conventional urethane pad member.

FIG. 23 is a graph showing the relationship between the friction coefficient and the number of running sheets in the silicone rubber pad member of the present invention.

FIG. 24 is a graph showing the relationship between the friction coefficient and the number of running sheets in a conventional silicone rubber pad member.

[Explanation of symbols]

1 tray, 5 paper feeding device, 6 paper feeding roller, 10 retard member, 11 pad member,
12 holders, 20/30/40 pad members,
21 base member, 22 ridge, 23 concave groove, 24 side member, 35 front side part, 36
Roller pressing portion, 37 upstream side portion, 41 protruding portion, 42 concave portion.

Claims (4)

[Claims] 1. A paper feed roller and a retarding member are arranged on the paper feed-out side so as to face a member on which a paper is placed, such as a paper feed tray, and the paper fed out by the paper feed roller is provided with a retarding member. In a sheet feeding device that separates and feeds sheets one by one, the surface of the retard member pad member, which is arranged facing the sheet feeding roller, in contact with the sheet is inclined at a predetermined angle with respect to the sheet conveyance direction. A sheet feeding device of an image forming apparatus, characterized in that it is configured by combining a ridge and a groove. 2. The protrusion and the groove are inclined at an angle of 0 to 60 ° with respect to the sheet conveying direction, the width is 0.5 to 8 mm, and the depth of the groove is 0 from the surface of the protrusion. The sheet feeding device of the image forming apparatus according to claim 1, wherein the sheet feeding device is set to 0.5 to 5 mm. 3. The sheet feeding device of the image forming apparatus according to claim 1, wherein the pad member is formed of a flat plate-like member, and the concave portion is formed in an arbitrary pattern on the entire surface with which the sheet abuts. . 4. The sheet feeding device of the image forming apparatus according to claim 1, wherein the pad member is made of silicone rubber.