JPH09146191A - Automatic document feeder - Google Patents

Abstract

(57) [Summary] [Objective] The automatic document feeder can be manufactured in a lightweight, simple and inexpensive manner by sufficiently exerting the belt pressing action of the press roller against the conveyor belt and reducing the weight thereof. [Structure] The press roller 11 includes a rotatable shaft 13 fixed to a pair of device frames 7a and 7b facing each other,
The roller body 14 is attached around the roller body 14, and the roller body 14 is formed of a porous member such as urethane foam or sponge having a radius larger than the distance between the shaft 13 and the contact glass CG surface. When the feeding device was set on the contact glass CG, the roller body 14 was deformed to press the conveyor belt 10 toward the contact glass CG.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder for automatically feeding a document to a predetermined position on a contact glass of a main body such as a copying machine.

[0002]

2. Description of the Related Art Generally, this type of automatic document feeder is
On the contact glass of the copying machine, an endless conveying belt wider than the largest original to be handled is stretched, and due to the friction of the conveying belt, the original is conveyed onto the contact glass of the copying machine. Therefore, in this type of automatic document feeder, it is necessary to apply an appropriate pressing force to the wide conveyance belt, which allows the conveyance force to be uniformly transmitted between the wide conveyance belt and the document. It is necessary to avoid uneven feeding of the original on the contact glass surface due to uneven belt tension so that the original is not fed or is bent and conveyed.

Conventionally, the following types of pressing means apply a document pressing force to the conveyor belt.

(1) As shown in FIG. 17 (a) or (b), a pressing roller b is put in a resin holder a, the holder a is attached to a mounting stay c, and a spring d is used in a pressing direction, that is, a wide width. It urges toward the conveyor belt e.

(2) As shown in FIGS. 18 (a) and 18 (b), a rubber roller g is added to the iron-based shaft f in the shape of a dango, and both ends of the shaft are inserted into a holder h from below and pressed by the weight of the shaft f. To do.

(3) As shown in FIG. 19, the coil spring j is replaced with a shaft, and the roller k is supported and pressed by the spring shaft j.

(4) As shown in FIG. 20 (a) or (b), the resin holder a and the spring d in FIG. 18 are leaf springs m, or the resin holder a is a cantilever type.

[0008]

[Problems to be Solved by the Invention] However, the above (1) to (4)
Since the conventional belt pressing means shown in Fig. 6 is of a type in which the weight of the shaft of the pressing roller or the spring load is used, heavy ones are used for the pressing roller, the shaft, etc., and the automatic document feeder itself It becomes heavy, and the operation for opening and closing the automatic document feeder with respect to the contact glass surface tends to be difficult.

Further, in the conventional belt pressing means (FIGS. 17, 19, and 20) shown in the above (1), (3), and (4), the stay c for attachment is required, and the above (2) In the conventional belt pressing means shown in FIG. 18 (FIG. 18), a holder h for mounting is required at the front and rear, and there is almost no flexibility such as adjusting the pressing force after setting.

Further, the above-mentioned conventional belt pressing means is
When a book or foreign matter is placed on the contact glass and the automatic document feeder is opened or closed, a strong shock is applied to the contact glass surface, which causes a problem that the contact glass is damaged.

Therefore, an object of the present invention is to solve the above-mentioned problems, to make the press roller lighter while sufficiently exerting the belt pressing action on the conveyor belt, and to easily and inexpensively manufacture the automatic document feeder. To provide.

Another object of the present invention is to provide an automatic document feeder which does not damage the contact glass even if a book or foreign matter is placed on the contact glass and the automatic document feeder is opened or closed.

[0013]

In order to achieve the above object, the present invention has a conveyor belt stretched between pulleys and placed on a contact glass of a main body apparatus such as a copying machine. In an automatic document feeder that conveys a document along the contact glass surface while pressing it against the contact glass side with a press roller, the press roller includes a rotatable shaft fixed to a pair of opposing device frames, and a surrounding shaft. In addition to the attached roller main body, the roller main body is formed of a porous member such as urethane foam or sponge having a radius larger than the distance between the shaft and the contact glass surface, and the document feeder is provided with a contact glass. When set on, the roller body deforms and presses the conveyor belt toward the contact glass side. Those were Unishi (claim 1).

In the present invention, the shaft is made of a synthetic resin that can be bent in the axial direction, and the shaft is elastically deformed in a through hole provided in the pair of device frames so that the shaft can be attached and detached. Item 2).

At least one outer circumference of the shaft is provided.
The roller body is formed in a non-circular shape having two overhanging portions, and the roller body made of a porous member is formed integrally with the roller body (claim 3).

[0016]

According to the first aspect of the present invention, the conveyor belt is stretched between the pulleys and placed on the contact glass of the main body apparatus such as a copying machine, and the conveyor belt is pressed from the inside to the contact glass side by the press roller. Meanwhile, in the automatic document feeder for conveying the document along the contact glass surface, the press roller is composed of a rotatable shaft fixed to a pair of opposed device frames, and a roller body mounted around the shaft. , The roller body is made of a porous material such as urethane foam or sponge having a radius larger than the distance between the shaft and the contact glass surface, and the roller body is set when the document feeder is set on the contact glass. Is deformed to press the conveyor belt toward the contact glass.
Therefore, in the state where the document feeder is set on the contact glass, the restoring force of the porous member such as urethane foam or sponge acts as a document pressing force on the transport belt.

This is because the restoring force of the porous member such as urethane foam or sponge is used as the belt pressing means instead of the conventional spring force or the weight of the roller itself being used as the belt pressing means. Conventional pressing spring,
It is possible to reduce the weight and cost of the document feeder by removing the weight from the attachment reinforcing member or the iron-based shaft. Since the shaft is made of synthetic resin, the weight is reduced and the weight is reduced as a whole, so that the opening / closing operation of the contact glass of the document feeder can be facilitated.

Further, since the roller body is deformed and the pressing area of the press roller against the conveyor belt is increased, it is possible to reliably convey the original.

According to a second aspect of the present invention, the shaft is made of a synthetic resin that can be bent in the axial direction, and the shaft is elastically deformed in a through hole provided in the pair of device frames so that the shaft can be attached and detached. Therefore, if you place a book or foreign matter on the contact glass and give a strong shock when opening and closing the automatic document feeder, the shaft will bend in the direction opposite to the platen glass, so the platen glass Does not damage. Further, even when the conveyor belt is replaced, the shaft can be attached or detached by simply inserting or pulling out both ends of the shaft into the through holes of the apparatus frame, so that the exchange operation is easy.

According to a third aspect of the invention, the outer circumference of the shaft is formed in a non-circular shape having at least one overhang portion,
Since the roller main body made of a porous member is formed integrally by being penetrated, even if the roller main body is deformed, it can be rotated by being driven by the conveyor belt.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments.

In FIG. 16, the automatic document feeder 1 is
Contact glass CG of a copying machine as an image forming apparatus
It is placed on the top and is openably and closably attached by a hinge mechanism (not shown). A normal copying optical system is built in the main body of the copying machine, and the standard for setting the original on the contact glass CG is set at the center (center standard) in the original width direction.

The automatic document feeder 1 feeds the originals on the original table 2 one by one to the entrance of the contact glass CG by the original feeding unit 3, delivers the originals to the conveying unit 4, and the conveying unit 4 Holds the original between the contact glass CG and sends it, conveys it to a predetermined stop reference position, positions it, and is subjected to exposure processing, and discharges the exposed original from the paper output unit 5 onto the paper output tray 6. It is like this.

The transport section 4 is arranged in a pair on the contact glass and has an inlet side pulley 8 and an outlet side pulley 9 which are pivotally supported by the transport frame 7, and the largest document to be handled which is wound between both pulleys. A wide endless conveyor belt 10 is provided, and the conveyor belt 10 is stretched so that its lower surface is in contact with the contact glass CG.

Inside the endless conveyor belt 10, a plurality of press rollers 11 for pressing the conveyor belt 10 from the inside onto the contact glass CG are arranged in the conveying direction. Here, four press rollers 11a to 11d
Is arranged in the document transport direction, and the pulley 9 on the document exit side is driven by a drive motor (not shown) to rotate the transport belt 10 to transport the document along the contact glass surface. . That is, the outlet side pulley 9 is a drive pulley and the inlet side pulley 8 is a driven pulley.
Reference numeral 12 denotes a mounting stay for the press roller 11. And
Press rollers 11a, 11b, which are adjacent to each other in the document transport direction,
Pulley 8 closer to the document entrance side than the distance between 11c and 11d
And the press roller 11a adjacent to the pulley are narrowed, and the pulley 8 on the inlet side of the conveyor belt 10 is
The pressing force of the press roller 11a adjacent to the press roller 11d and the pressing roller 11d adjacent to the outlet side pulley 9 to the conveyor belt 10 is made larger than the pressing force of the other press rollers 11b and 11c. Therefore, even if there is some slack in the vicinity of the document inlet on the document setting surface side of the transport belt 10, the slack is eliminated by the press roller 11a closest to the document inlet, and the sheet is strongly stretched.

The structure of the press roller 11 is shown in FIGS. The press roller 11 has a shaft 13 made of synthetic resin in the center, and a roller body 14 around the shaft 13 is a porous member such as soft urethane foam or sponge having a high flexibility. It is composed of urethane foam of the cylindrical body 14a having a radius larger than the distance from.

The synthetic resin shaft 13 is surrounded by
In addition to having bearing shaft portions 13a at both ends of the shaft, blades 13b crossing each other in a cross shape are provided as rotation preventing portions for the urethane cylindrical body 14a. A cross-shaped groove 14b is provided in the center of the urethane foam cylindrical body 14a in advance, and the blade 13b of the shaft 13 is inserted into the groove 14b to assemble them together.

Press roller 11 assembled together
As shown in FIG. 4, the shaft portions 13a and 13a are inserted between the front frames 7a of the carrier frame 7 and the through holes 15 and 15 of the rear frame 7b while being curved in an arc shape along the axial direction. Thus, the carrier frame 7 is rotatably supported.

In order to make it possible to adjust the pressing force on the conveyor belt 10, the penetration holes 15 of the frames 7a, 7b are set in a plurality of sets, here 15a, 15b, 15c, with different height positions and conveyance direction positions. There are only 3 sets,
Of these, the shaft portions 13a at both ends of the shaft 13 are inserted into a set of heights at which an appropriate belt pressing force is obtained.

FIG. 5 shows the conveyor belt 10 and the press roller 11 before contacting the contact glass at this time.
FIG. 6 shows the pressing relationship between the conveyance belt 10 and the press roller 11 after the document feeder 1 is brought into contact with the contact glass.

That is, before contact with the contact glass, the roller body 14 is also affected by the tension of the conveyor belt 10.
The barrel cylindrical body 14a, which is a barrel, maintains its cross-sectional shape in a substantially original shape (circular shape), and as a result, the conveyor belt 10 is in a state of being protruded downwardly before and after the roller body 14. However, after the document feeder 1 is placed on the contact glass CG and brought into contact with the contact glass CG, the urethane cylindrical body 14a passes through the conveyor belt 10 until the conveyor belt 10 is bonded to the contact glass CG almost flatly. Is pressed from the contact glass CG side, and the urethane cylindrical body 14a is deformed into a shape in which the lower chord of the circular cross section is missing. Therefore, a downward restoring force P as shown in FIG. 6 is generated in the urethane cylindrical body 14a, and the conveyor belt 10 has the restoring force P of the urethane cylindrical body 14a.
It is pressed onto the contact glass CG.

In other words, the urethane cylinder 14a, which is the roller body 14, includes the shaft 13 and the contact glass CG.
The roller main body 1 has a radius larger than the distance from the surface and when the document feeder is set on the contact glass CG.
4 is deformed to press the conveyor belt 10 toward the contact glass CG side. Therefore, as the material of the roller body 14 that generates the pressing force by the restoring force, a porous material having such flexibility is sufficient, and not only urethane but also foam such as sponge is used. It can also be used.

According to the above, the original pressing force of the conveyor belt 10 can be reduced without using the spring force and the weight of the roller as in the conventional case.
Since it is obtained by utilizing the restoring force of the porous member of urethane forming the press roller 11, the weight and cost of the original feeding device 1 are reduced, and the weight reduction makes it possible to open and close the contact glass of the original feeding device 1. It is possible to improve.

Further, the urethane cylinder 14a, which is the roller body 14, is deformed, and the conveyor belt 10 of the press roller 11 is deformed.
Since the pressing area with respect to is increased, the document can be reliably transported.

Further, since the shaft 13 of the press roller 11 is made of synthetic resin, it is lightweight, and both ends of the shaft are inserted into the through holes 15 of the frames 7a and 7b even when the conveyor belt 10 is replaced. Easy to install and remove. Moreover, since the press roller 11 is of a type in which the shaft 13 both end shaft portions 13a are inserted into any one of a plurality of sets of penetration holes 15a, 15b, 15c having different height positions provided in the frames 7a, 7b. The pressing force on the conveyor belt 10 can be easily adjusted by changing the set (height) of the insertion holes 15a, 15b, 15c to be inserted. See also hole 1
It is also possible to provide a plurality of sets 5 of the frames 7a and 7b at different positions in the carrying direction, and by selectively using one set of these through holes 15, the press roller 11 It is possible to adjust the pressing position appropriately.

In short, according to the above construction, it is possible to increase the convenience of mounting, the flexibility of the pressing force and the pressing position, and contribute to the weight reduction and the cost reduction. Further, since the parts not grounded from the frames 7a and 7b are made of resin, that is, there is no floating metal, there is no adverse effect due to static electricity (sparks).

FIG. 7 shows the shaft 13 made of synthetic resin,
In this embodiment, two or more urethane cylinders 14c in the shape of rollers 16 having a short axial width are fitted as the roller body 14 in this case, four in this case, so as to be movable in the axial direction. Since each roller 16 that constitutes the roller body 14 can freely move along the shaft 13, as shown in FIG. 8A, when the width of the document 17 is large, the interval between the rollers 16 is increased, and When the original 17 has a small width, as shown in FIG. 8B, it is possible to reduce the distance between the rollers 16 and bring them closer to the original reference side.

9 to 12 show the press roller 1 respectively.
1 is another embodiment.

As described above, the material of the urethane cylindrical body 14a or 14c, which is the roller body 14, has a radius larger than the distance between the shaft 13 and the contact glass CG surface, and the document feeder is placed on the contact glass CG. A porous member that deforms the roller body 14 to press the conveyor belt 10 toward the contact glass CG side when set to is sufficient.

FIG. 9 shows a structure in which a press roller 11 is constructed as a structure of a tire roller 18 which is rotatable around a shaft 13 by filling air 18b inside a hollow annular body 18a whose outer skin is made of skin-like rubber. is there. In other words, this is an example in which the cushion restoration member of the roller body 14 is configured by the hollow annular body 18a. FIG. 10 shows an example in which the surface of a foamed plastic 19 such as urethane foam is covered with a skin member 20 made of an elastic material such as rubber to form the roller body 14 of the press roller 11.

In FIG. 11, a large number of blades 22 made of an elastic material are preliminarily integrally formed around the cylindrical core material 21 in a length that covers the amount of bending when pressed, and the press roller 1 is formed.
1 is an example of configuring 1. The elastic material used for the core material 21 and the blades 22 may be either rubber or resin.

In the above embodiment, the synthetic resin shaft 13 is used.
Although the blade having the cross-shaped cross-section blade 13b is used as the above, it is not limited to this, and any sectional shape can be adopted as long as it functions as a rotation stopping portion. For example, as shown in FIG. 12, (a) rectangle, (b) two-blade shape, (c) triangle, and (d) ratchet shape can be used.

Further, the conveyor belt 10 of the press roller 11
If there is a restriction on the mounting position of the press roller 11, the pressing force against is adjusted by adjusting the foam density and the outer shape of the urethane cylindrical body 14a of the roller body 14 as shown in FIGS. 13 (a) and 13 (b). Can be adjusted.

Further, as to the method of attaching the press roller 11, as shown in FIG. 14, the through hole 15 provided in the frames 7a and 7b is used to attach the large diameter portion 15e.
A bayonet type having a small diameter portion 15f positioned at the time of functioning, or as shown in FIG. 15, a resin bearing member 23 is fitted in the penetration hole 15 as a wear resistant measure. You can

[0045]

In summary, according to the present invention, the following excellent effects can be obtained.

According to the first aspect of the present invention, the conveyor belt is stretched between the pulleys and placed on the contact glass of the main body apparatus such as a copying machine, and the conveyor belt is pressed from the inside to the contact glass side by the press roller. In the automatic document feeder that conveys the document along the contact glass surface while pressing,
The press roller is composed of a rotatable shaft fixed to a pair of opposing device frames, and a roller main body attached to the periphery thereof, and the roller main body is more than the distance between the shaft and the contact glass surface. It is made of a porous material such as urethane foam or sponge having a large radius, and when the document feeder is set on the contact glass, the roller body is deformed and presses the conveyor belt toward the contact glass. As a result, the original document feeder can be made lighter and the cost can be reduced compared to the conventional case where the spring force and the self-weight of the roller are used, and the weight reduction makes it easy to open and close the original document feeder with respect to the contact glass. Can be Further, since the roller body is deformed and the pressing area of the press roller against the conveyor belt is increased, it is possible to reliably convey the original.

According to the second aspect of the present invention, the shaft is made of synthetic resin which can be bent in the axial direction, and the shaft can be attached and detached by elastically deforming the shaft in the through holes provided in the pair of device frames. With this configuration, when a book or foreign matter is placed on the contact glass and a strong shock is applied when opening or closing the automatic document feeder, the shaft bends in the direction opposite to the platen glass. Does not damage the glass. Further, even when the conveyor belt is replaced, the shaft can be attached or detached by simply inserting or pulling out both ends of the shaft into the through holes of the apparatus frame, so that the exchange operation is easy. Since the roller body is composed of the cylindrical body made of urethane foam, a lightweight and low-cost press roller can be concretely obtained.

According to the invention of claim 3, the outer periphery of the shaft is formed in a non-circular shape having at least one overhang portion, and the roller main body made of a porous member is penetrated to be integrally formed. Even if the roller body is deformed, it can be rotated by following the conveyor belt.

[0049]

[Brief description of the drawings]

FIG. 1 is a development perspective view showing an embodiment of a press roller of an automatic document feeder according to the present invention.

FIG. 2 is a side view showing the press roller of FIG.

FIG. 3 is a view showing a through hole of a conveyance frame into which a shaft end portion of the press roller of FIG. 1 is inserted.

FIG. 4 is a view showing a state in which the press roller is curved for insertion into the penetration hole of FIG.

FIG. 5 is a view showing a cross section of a press roller in the automatic document feeder of the present invention in a state before contact with contact glass.

FIG. 6 is a diagram showing a cross section of a press roller in the automatic document feeder of the present invention in a state when contact glass is in contact.

FIG. 7 is a developed perspective view showing another embodiment of the press roller of the automatic document feeder of the present invention.

8 is a plan view showing the positions of rollers forming the press roller of FIG. 7. FIG.

9A and 9B show a modified embodiment of the press roller of the automatic document feeder of the present invention, in which FIG. 9A is a perspective view and FIG. 9B is a sectional view.

FIG. 10 is a sectional view showing another modified embodiment of the press roller of the automatic document feeder according to the present invention.

FIG. 12 is a sectional view showing a sectional shape of a shaft in a press roller of the automatic document feeder of the present invention.

FIG. 13 is a sectional view showing the size and sectional shape of a press roller of the automatic document feeder of the present invention.

FIG. 14 is a view showing the shape of a through hole of the automatic document feeder of the present invention.

FIG. 15 is a diagram showing a state in which a shaft is inserted into a through hole of the automatic document feeder of the present invention through a bearing member.

FIG. 16 is a diagram showing an outline of an automatic document feeder according to an embodiment of the present invention.

FIG. 17 is a diagram showing a belt pressing unit of a conventional automatic document feeder.

FIG. 18 is a view showing another belt pressing means of the conventional automatic document feeder.

FIG. 19 is a view showing another belt pressing means of the conventional automatic document feeder.

FIG. 20 is a view showing another belt pressing means of the conventional automatic document feeder.

[Explanation of symbols]

 1 Automatic Document Feeding Device 2 Document Plate 3 Document Feeding Unit 4 Conveying Unit 5 Discharging Unit 6 Discharging Tray 7 Conveying Frame 7a Front Frame 7b Rear Frame 8 Entrance Pulley 9 Exit Pulley 10 Conveyor Belt 11 Press Rollers 11a to 11d Press roller 12 Mounting stay 13 Synthetic resin shaft 13a Bearing shaft portion 13b Blade (rotation stop portion) 14 Roller body 14a Urethane cylindrical body 14b Groove 14c Urethane cylindrical body 15 Penetration hole 15a to 15d Penetration hole 15e Large diameter part 16 Roller 17 Document 18 Tire roller 18a Hollow annular body 18b Air 20 Skin member 21 Core material 22 Blade 23 Bearing member CG Contact glass P Restoring force (pressing force) a Resin holder b Pressing roller c Mounting stay d Spring f Iron shaft g Rubber roller h Holder j Coil spring k Russia

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[Procedure amendment]

[Submission date] March 14, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a development perspective view showing an embodiment of a press roller of an automatic document feeder according to the present invention.

FIG. 2 is a side view showing the press roller of FIG.

FIG. 3 is a view showing a through hole of a conveyance frame into which a shaft end portion of the press roller of FIG. 1 is inserted.

FIG. 4 is a view showing a state in which the press roller is curved for insertion into the penetration hole of FIG.

FIG. 5 is a view showing a cross section of a press roller in the automatic document feeder of the present invention in a state before contact with contact glass.

FIG. 6 is a diagram showing a cross section of a press roller in the automatic document feeder of the present invention in a state when contact glass is in contact.

FIG. 7 is a developed perspective view showing another embodiment of the press roller of the automatic document feeder of the present invention.

8 is a plan view showing the positions of rollers forming the press roller of FIG. 7. FIG.

9A and 9B show a modified embodiment of the press roller of the automatic document feeder of the present invention, in which FIG. 9A is a perspective view and FIG. 9B is a sectional view.

FIG. 10 is a sectional view showing another modified embodiment of the press roller of the automatic document feeder according to the present invention.

FIG. 11 is a sectional view showing another modified embodiment of the press roller of the automatic document feeder of the present invention.

FIG. 12 is a sectional view showing a sectional shape of a shaft in a press roller of the automatic document feeder of the present invention.

FIG. 13 is a sectional view showing the size and sectional shape of a press roller of the automatic document feeder of the present invention.

FIG. 14 is a view showing the shape of a through hole of the automatic document feeder of the present invention.

FIG. 15 is a diagram showing a state in which a shaft is inserted into a through hole of the automatic document feeder of the present invention through a bearing member.

FIG. 16 is a diagram showing an outline of an automatic document feeder according to an embodiment of the present invention.

FIG. 17 is a diagram showing a belt pressing unit of a conventional automatic document feeder.

FIG. 18 is a view showing another belt pressing means of the conventional automatic document feeder.

FIG. 19 is a view showing another belt pressing means of the conventional automatic document feeder.

FIG. 20 is a view showing another belt pressing means of the conventional automatic document feeder.

[Description of Reference Signs] 1 automatic document feeder 2 document table 3 document feeder 4 transport unit 5 discharge unit 6 discharge tray 7 transport frame 7a front frame 7b rear frame 8 inlet side pulley 9 outlet side pulley 10 transport belt 11 Press rollers 11a to 11d Press rollers 12 Mounting stays 13 Synthetic resin shafts 13a Bearing shaft portions 13b Blades (rotation preventing portions) 14 Roller bodies 14a Urethane cylindrical bodies 14b Grooves 14c Urethane cylindrical bodies 15 Penetration holes 15a to 15d Penetration holes 15e Large diameter part 16 Roller 17 Manuscript 18 Tire roller 18a Hollow annular body 18b Air 20 Skin member 21 Core material 22 Blade 23 Bearing member CG Contact glass P Restoring force (pressing force) a Resin holder b Pressing roller c Mounting stay d Spring f Iron shaft g Rubber roller h Holder j Coil spring k roller

Claims (3)

[Claims] 1. A contact belt is stretched between pulleys and placed on a contact glass of a main body apparatus such as a copying machine, and the original is contact glass while pressing the transfer belt from the inside toward the contact glass side with a press roller. In an automatic document feeder for transporting along a surface, the press roller is composed of a rotatable shaft fixed to a pair of opposing device frames and a roller body mounted around the shaft, and the roller body is , A porous member such as urethane foam or sponge having a radius larger than the distance between the shaft and the contact glass surface, and when the document feeder is set on the contact glass, the roller body is deformed and An automatic document feeder, wherein a conveyor belt is pressed against the contact glass side. 2. The shaft is made of synthetic resin that can be bent in the axial direction, and the shaft is elastically deformed in a through hole provided in the pair of device frames so that the shaft can be attached and detached. 1. The automatic document feeder according to 1. 3. The shaft according to claim 1, wherein the outer circumference of the shaft is formed in a non-circular shape having at least one overhang portion, and the roller main body made of a porous member is penetrated to be integrally formed. The automatic document feeder described.