JP2000001238A - Automatic document transport device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an endless belt from being stained by the edge of a pressing member by making the length of the belt pressing member correspond to a document transport area, and pressing the endless belt by a pressing plate having a bent part. SOLUTION: A belt pressing member 75 comprises a pressing plate 751 f formed of a sheet member having elasticity such as a polyethylene terephthalate(PET) resin sheet member of the like, and has a length corresponding to a document transport area in the end direction of an endless belt 74. The pressing plate 751 is bent to be projected toward the endless belt 74, and both end parts in the moving direction (lateral direction) of the endless belt 74 are stuck to the lower surface of a base plate 712 constituting a support frame 71 by pressure sensitive double coated adhesive tapes 77, 77 or suitably by an adhesive. The pressing plate 751 formed by thus bending the sheet member is constructed so that the bent part 751a presses the back of the endless belt 74 passing the lower side, that is, the transparent plate side between a driving roller 72 and a driven roller 73.

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 provided in a document processing machine such as an electrostatic copying machine, a facsimile or an image reader.

[0002]

2. Description of the Related Art In recent years, copiers have come to use an automatic document feeder which automatically and automatically supplies a plurality of documents to a document set position on the upper surface of a transparent plate with the speeding up and automation of copying processing. I have. An automatic document feeder for automatically feeding a plurality of documents sequentially to a document processor such as a facsimile or an image reader has been widely and practically used. This kind of automatic document feeder includes a document table on which a document is placed, document loading means for feeding the document placed on the document table toward a transparent plate of a document processing machine, and a document feeding means. A transport belt mechanism that positions the fed document at a predetermined position on the transparent plate and transports the document along a document transport path formed on the transparent plate, and a document discharging unit that discharges the document transported by the transport belt mechanism. Is provided.

The transport belt mechanism comprises a support frame, a drive roller and a driven roller disposed in parallel with the support frame at intervals in the transport direction, the drive roller, the driven roller, and the support frame. And a belt pressing means disposed between the driving roller and the driven roller for pressing the endless belt toward the transparent plate. The belt pressing means is composed of a plurality of pressing rollers disposed on the endless belt at predetermined intervals in the width direction.

[0004]

In the automatic document feeder provided with the above-described transfer belt mechanism, the endless belt and the document are rubbed at the positions corresponding to the edge portions at both ends of each of the pressing rollers. Occurs. For this reason, when a document on which images are printed on both sides is conveyed, streak-like dirt is generated on the endless belt in a portion passing through both ends of each pressing roller. The dirt on the endless belt causes a document to be conveyed thereafter to be stained. In order to solve such a problem, a roller having substantially the same length as the width of the endless belt may be used instead of the pressing roller. However, the roller increases the weight and the cost. There is.

The present invention has been made based on the above-mentioned facts, and a main technical problem of the present invention is to provide a transport belt mechanism capable of preventing the endless belt from being stained by the edge of a pressing member for pressing the endless belt. And an automatic document feeder provided with the automatic document feeder.

[0006]

According to the present invention, there is provided a transport belt mechanism for transporting a document along a document transport path formed on a transparent plate of a document processor. The conveying belt mechanism, the supporting frame, a driving roller and a driven roller disposed in parallel with the supporting frame at an interval in the conveying direction, the driving roller and the driven An endless belt wound around a roller and the support frame, and a belt pressing member disposed between the driving roller and the driven roller to press the endless belt toward the transparent plate. The belt pressing member includes a pressing plate disposed in the width direction of the endless belt, having a length corresponding to a document conveying area, and mounted on a bottom plate of the support frame. Equipped with a curved part protruding toward the endless belt The curved portion presses the endless belt, an automatic document feeder is provided, characterized in that.

The pressing plate is made of an elastic sheet member, and both end portions of the endless belt in the moving direction are adhered to the lower surface of the bottom plate with a double-sided adhesive tape or an adhesive. Further, the pressing plate is made of an elastic sheet member,
Both ends in the moving direction of the endless belt are engaged with a plurality of locking claws provided on the bottom plate. Further, the pressing plate is formed of a plate material having elasticity, and both ends in the moving direction of the endless belt are engaged with a plurality of locking claws provided on the bottom plate. The pressing plate is formed of a synthetic resin material, and both end portions in the moving direction of the endless belt are supported by the bottom plate via a spring member.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an automatic document feeder constructed according to the present invention will be described below in detail with reference to the accompanying drawings.

FIGS. 1 and 2 show an upper end portion of an electrostatic copying machine 2 and an automatic document feeder 4 mounted thereon. The electrostatic copying machine 2 has a housing 6, and on the upper surface of the housing 6, a transparent plate 8 (FIG. 2), which may be a glass plate, is provided. On one side (left side in FIG. 2) of the transparent plate 8, a document regulating member 1 for defining a document set reference position G is provided.
0 is disposed, and a stationary mounting member 12 is disposed on the other side (the right side in FIG. 2). The automatic document feeder 4 configured in accordance with the present invention includes a housing 6 of the electrostatic copying machine 2.
1 is pivotally mounted between a closed position indicated by a solid line in FIG. 1 and an open position indicated by a two-dot chain line around a pivot axis extending along the rear edge of the transparent plate 8. Electrostatic copier 2
When the original is manually placed on the transparent plate 8, the automatic document feeder 4 is opened to expose the transparent plate 8, the original is placed at a required position on the transparent plate 8, and With the document feeder 4 closed, the transparent plate 8 and the document placed thereon are covered. When placing a document on the transparent plate 8, the document is required by placing one edge of the document against the leading edge of the document regulating member 10 and positioning the trailing edge of the document at the document setting reference position G. Position. When the document is automatically loaded onto the transparent plate 8 using the automatic document feeder 4 and is automatically output from the transparent plate 8, the automatic document feeder 4 is positioned at the closed position.

Continuing with FIG. 1, the illustrated automatic document feeder 4 includes a front cover 14 and a rear cover which are disposed at an interval in the front-rear direction (the direction perpendicular to the plane of FIG. 2). 16 is included. The front cover 14 and the rear cover 16 can be formed from an appropriate synthetic resin. A rear support substrate (not shown) is provided in the rear cover 16, and such a rear support substrate is connected via a mounting mechanism (not shown) which may itself be a known form. Thus, it is mounted on the upper surface of the housing 6 of the electrostatic copying machine 2 so as to be pivotable. Various components of the automatic document feeder 4 are directly or indirectly supported by the rear support substrate. A document placing means 18 and a document discharge tray 20 are provided between the front cover 14 and the rear cover 16. The original placing means 18 includes an original table 22 extending upward from the left end to the right rear end in FIG. 2 and an auxiliary table rotatably mounted at the rear end of the original table 22. 24. The document table 22 has a pair of width regulating members 26 movably in the width direction. The pair of width regulating members 26 are connected to each other below the document table 22 via a well-known rack and pinion mechanism (not shown), and approach each other in conjunction with each other. In the direction and away from each other.
The document discharge tray 20 is disposed below the document placing means 18 and has a document placing surface 201 formed in a mountain shape when viewed from the front-back direction (the direction perpendicular to the paper surface in FIG. 2). A left end cover 28 is disposed between the left ends of the front cover 14 and the rear cover 16, and a right end cover 29 is disposed between the right ends.

Continuing the description with reference to FIGS. 1 and 2, a forward feed means 30 is provided downstream of the document table 22 in the transport direction. The advance means 30 is
A guide plate 32 is provided extending downstream of the document table 22 in the transport direction. An opening is formed on the upstream side of the guide plate 32, and a forward feed roller 34 constituting the forward feed means 30 is disposed below the opening. The forward feed roller 34 is formed of an elastic material having a large friction coefficient such as urethane rubber, and is disposed so that a part of the outer peripheral surface slightly projects upward from an opening formed in the guide plate 32. The rotation axis (not shown) of the forward feed roller 34 is
It is operatively connected to an electric motor 35 as a drive source via a power transmission mechanism (not shown).

Above the forward feed roller 34, a forward feed pressure mechanism 36 constituting the forward feed means 30 is provided. The forward feed pressurizing mechanism 36 includes a rotating shaft 36 disposed above the forward feed roller 34 in parallel with the forward feed roller 34.
2, and a pressing plate 364 which has an upper end fixed to the rotating shaft 362 and a lower end placed on the original table 22 and acting on the original (P) inserted on the guide plate 32. . The pressing plate 364 is formed of an elastic thin plate made of a stainless steel plate in the illustrated embodiment, and the upper end thereof is fixed to the rotating shaft 362 by a fixing means such as a screw. Feed roller 34
At the upper position of the uppermost document placed on the document table 22, it is positioned at an operating position for pressing the original and pressing the original, and a non-operating position separated from the original. The rotating shaft 362 constituting the forward feed pressing mechanism 36 is provided with side plates 39, 39 provided at front and rear ends of a support substrate 38 disposed above the forward feed roller 34.
(Only the rear side plate 39 is shown in FIG. 2). The turning shaft 362 is connected to a solenoid (not shown) via a link mechanism, and is turned in a predetermined direction when the solenoid is urged.
When the solenoid is de-energized, it is rotated in the direction opposite to the predetermined direction. Therefore, the pressing plate 364 attached to the rotating shaft 362 is biased by a solenoid (not shown) so that the rotating shaft 3
When the document 62 is rotated in a predetermined direction, it presses the document inserted above the guide plate 32, the solenoid is deenergized, and the rotating shaft 3 is rotated.
When 62 is rotated in the direction opposite to the predetermined direction, it is separated from the document.

A paper feed roller 40 is disposed downstream of the advance mechanism 30. The paper feed roller 40 is formed of a material having a large friction coefficient such as urethane rubber,
The rotating shaft is operatively connected to an electric motor 35 as a drive source via a power transmission mechanism (not shown). The paper feed roller 40 is disposed so that a part of the outer peripheral surface slightly projects upward from an opening formed in the guide plate 32.

An original separating mechanism 50 is disposed above the paper feed roller 40. The document separation mechanism 50 includes a separation roller 51 in the illustrated embodiment. The separation roller 52 includes a fixed shaft 52 and a cylindrical portion 53 formed of an appropriate synthetic resin and rotatably disposed on the fixed shaft 52.
And a surface layer portion 54 formed of an elastic material having a large coefficient of friction such as urethane rubber and attached to the outer peripheral surface of the cylindrical portion 53.
And a torque limiter mechanism 55 disposed between the fixed shaft 52 and the cylindrical portion 53, and the surface layer portion 54 is disposed in contact with the outer peripheral surface of the roller portion 46 of the paper feed roller 40. ing. The torque limiter mechanism 55 includes a cylindrical portion 53.
And a spring clutch mechanism for fixing the tubular portion 53 to the fixed shaft 52 when a predetermined or more driving torque acts on the fixed shaft 52.
The separation roller 51 having the torque limiter mechanism 55
It does not constitute a new feature in the automatic document feeder constituted by the present invention, and the constitution itself may be a known form, and therefore, for details of the constitution,
The description is omitted in this specification. In the illustrated embodiment, the separation roller 52 is used as the document separation mechanism 50.
However, as the document separation mechanism 50, a separation belt mechanism or another separation mechanism can be used.

A pre-separating means 60 is disposed upstream of the document separating mechanism 50 in the direction of conveyance so as to face the paper feed roller 40. The pre-separation means 60 includes a front segregation support plate 64 disposed in the axial direction of the paper feed roller 40 and having an upper end attached to the support substrate 38 by a screw 52, and an upper end formed at a lower end of the front segregation support plate 64. The front handling plate 66 is mounted. The pre-separating plate 66 is formed of an elastic sheet member such as a polyethylene terephthalate (PET) resin sheet member, and the upper end thereof is attached to the front-separating support plate 66 by a fixing member such as an adhesive or a double-sided adhesive tape. ing.

Continuing the description with reference to FIG. 2, a transport belt mechanism 70 is provided below the document placing means 18. The transport belt mechanism 70 includes a support frame 71, a driving roller 72 and a driven roller 73 disposed in parallel with the support frame 71 at intervals in the transport direction, and the drive roller 72.
And a plurality of endless belts 74 wrapped around the driven roller 73 and the support frame 71, and a plurality of belts disposed between the drive roller 72 and the driven roller 73 in the transport direction (the left-right direction in FIG. 2). And a belt pressing member 75. The drive roller 72 and the driven roller 73 are connected to the front and rear side plates 711, 711 of the support frame 71.
(Only the rear side plate 711 is shown in FIG. 2), which is rotatably supported at both ends in the conveyance direction, and the drive roller 72 is transmission-coupled to an electric motor (not shown) via a suitable power transmission mechanism. Have been. The lower traveling portion of the endless belt 74 of the transport belt mechanism 70 thus configured is extended along the transparent plate 8 of the electrostatic copying machine 2, and a document transport path 76 is defined between the two. .

Next, regarding the belt pressing member 75, FIG.
This will be described with reference to the embodiments shown in FIGS. In the first embodiment shown in FIG. 3, the belt pressing member 75 includes a pressing plate 751 made of an elastic sheet member such as a polyethylene terephthalate (PET) resin sheet member, and conveys the document in the width direction of the endless belt 74. It has a length corresponding to the area. The pressing plate 751 projects toward the endless belt 74 and is curved, and the endless belt 74 is bent.
In the moving direction (the left-right direction in FIG. 3), both sides are attached to the lower surface of the bottom plate 712 forming the support
7, 77 or an appropriate adhesive.
The pressing plate 7 formed by curving the sheet member in this manner
51, the curved portion 751a presses the lower surface of the endless belt 74 passing between the driving roller 72 and the driven roller 73, that is, the lower surface of the endless belt 74. Since the pressing plate 751 in the first embodiment shown in FIG. 3 has a length corresponding to the document transport area of the endless belt 74, the edge of the document transport area wants to exist. It is possible to prevent the endless belt from being stained due to the edge of the pressing member. The pressing plate 751 is
Since it is made of a sheet member, it can be manufactured lightweight and inexpensively.

In the second embodiment shown in FIG. 4, the mounting structure of the pressing plate 751 made of an elastic sheet member to the bottom plate 712 in the first embodiment is changed. That is, locking claws 712a, 712a formed by cutting and raising downward at predetermined intervals in the transport direction are provided at positions on the bottom plate 712 where the pressing plate 751 is mounted. Then, the pressing plate 751 is protruded toward the endless belt 74 to be curved, and both sides in the moving direction of the endless belt 74 are engaged with the locking claws 712a, 712a, respectively, and mounted. In this embodiment, the double-sided adhesive tape is not required as compared with the first embodiment, and the mounting work is easier.

In the third embodiment shown in FIG. 5, the belt pressing member 75 is formed of a spring steel plate. The pressing plate 753 formed of a spring steel plate has a length corresponding to the document conveying area in the width direction of the endless belt 74, and has a curved portion 753a at the center. Pressing plate 753
A plurality of notches 753b are formed on both sides of the endless belt 74 in the moving direction of the
3c is provided. On the other hand, the bottom plate 71 of the support frame 71
2, an opening 712b extending in the width direction is formed. The opening 712b has a length in the width direction corresponding to the pressing plate 753. In addition, the bottom plate 712 has, on both sides in the moving direction of the endless belt 74 in the opening 712b,
A plurality of locking claws 7 formed by cutting and raising upward at intervals corresponding to the plurality of support portions 753c of the pressing plate 753.
12c is provided. Then, the plurality of support portions 753c of the pressing plate 753 are engaged with the plurality of locking claws 712c, and the curved portion 753a is projected downward through the opening 712b, so that the lower side, that is, the transparent portion between the driving roller 72 and the driven roller 73. The rear surface of the endless belt 74 passing through the plate 8 is pressed. The third embodiment configured as described above also has the same operation and effects as those of the first and second embodiments. In the embodiment shown in FIG. 5, the pressing plate 753 is formed of a spring steel plate. However, the pressing plate 753 may be formed of a suitable elastic plate material such as synthetic resin in the same manner as the embodiment shown in FIG. A similar effect can be obtained.

In the fourth embodiment shown in FIG. 6, the belt pressing member 75 is formed of a synthetic resin. The pressing plate 754 formed of a synthetic resin has a curved portion 754a at the center and a plurality of cutouts 754b at both sides similarly to the pressing plate 753 in the third embodiment shown in FIG. A plurality of support portions 754c are provided. Note that the pressing plate 754 in this embodiment is
It is not necessary that the synthetic resin material has elasticity. on the other hand,
An opening 712b extending in the width direction is formed in the bottom plate 712 of the support frame 71 similarly to the third embodiment shown in FIG. 5, and pressing plates 75 are provided on both sides of the opening 712b in the transport direction.
A plurality of locking holes 712 formed at intervals corresponding to a plurality of spring support portions 754c provided on both side portions of the four.
d is provided. Then, the curved portion 7 of the pressing plate 754
The opening 54 a is formed in the bottom plate 712 of the support frame 71.
12b from above, and a plurality of spring support portions 754c
, Each with a coil spring 77, with both ends of
Engage with 12d. Accordingly, in the embodiment shown in FIG. 6, the curved portion 754 a of the pressing plate 754 presses the back surface of the endless belt 74 by the spring force of the coil spring 77.

Returning to FIG. 2, the description will be continued, and a document carrying path 80 is formed between the document carrying path 705 and the paper feed roller 40. This document carrying path 80 is defined by an inner guide plate 801 and an outer guide plate 802. A registration roller pair 82 is provided in the document carrying path 80. The pair of registration rollers 82 is
21 and a driven roller 822. The drive roller 821 of the pair of registration rollers 82 is operatively connected to an electric motor (not shown) via a suitable power transmission mechanism.

A document discharging means 90 is provided on the right side of the document conveying path 76 in FIG. The original discharging means 90
Includes a document discharge path 92, a pair of conveying rollers 94 disposed in the document discharge path 92, and a discharge roller pair 96 disposed at a discharge side end of the document discharge path 92. The transport roller pair 94 includes a drive roller 941 and a driven roller 942, and the discharge roller pair 96 also includes a drive roller 961 and a driven roller 962. Driving roller 941 of conveying roller pair 94 and driving roller 9 of discharging roller pair 96
Numeral 61 is drivingly connected to an electric motor (not shown) via an appropriate power transmission mechanism.

The automatic document feeder in the illustrated embodiment is configured as described above, and its operation and effect will be described below. In performing the copying operation, the operator first places the document P to be copied on the document table 22 and inserts the document P forward and inserts the front end of the document P into the forward feed roller 32.
On the upper side of. Then, when the copy start key is pressed by the operator, the solenoid (not shown) of the forward feed pressing mechanism 36 is urged, the pressing plate 364 is positioned at the operation position, and the document P inserted on the guide plate 32 is pressed. I do. The electric motor 35 is driven simultaneously with the pressing of the document P by the pressure plate 364, and the forward feed roller 34 and the paper feed roller 40 are driven to rotate in the direction indicated by the arrow in FIG. The rotation of the forward feed roller 34 in the direction indicated by the arrow in FIG. 2 causes the contact between the outer peripheral surface of the forward feed roller 34 and the lower surface of the lowermost document in the document layer inserted on the guide plate 32. The original is sent out by the frictional conveying force. At this time, the originals on the original layer are moved in the transport direction due to friction between each other, but a small number (1 to 3) of the originals are transported downstream by being regulated by the front separating means 60.

As described above, the original document regulated to a small number (1 to 3 sheets) by the action of the pre-separating means 60
When the document 2 passes through the separation roller 51 of the document separation mechanism 50, only the lowermost document is separated and conveyed to the document carrying path 80. Then, the front end of the document conveyed to the document carrying path 80 is brought into contact with the nip portion of the registration roller pair 82 in a non-operating state, and the primary sheet feeding is completed.

When the primary paper feeding is completed as described above,
The registration roller pair 82 and the transport belt mechanism 70 are operated to position the trailing edge of the primary fed document at the document setting reference position G on the transparent plate 8. Then, an exposure operation is performed. When the exposure operation is completed, the transport belt mechanism 7
The pair of transport rollers 94 and the pair of discharge rollers 96 of the document discharge means 90 and the discharge roller 96 are operated, and the document which has been exposed on the transparent plate 8 is passed through the document discharge path 92 to the document discharge tray
The document is discharged onto the original placing surface 201 of the “0” document.

[0026]

The automatic document feeder according to the present invention is constructed as described above, and has the following effects.

That is, the belt pressing member of the transport belt mechanism comprises a pressing plate disposed in the width direction of the endless belt and having a length corresponding to the document transport area and mounted on the bottom plate of the support frame. The plate has a curved portion protruding toward the endless belt, and the curved portion is configured to press the endless belt. Therefore, since there is an edge portion in the document conveyance area, the pressing member presses the endless belt. Of the endless belt caused by the edge portion can be prevented.
Further, since the belt pressing member is formed of a pressing plate, it can be manufactured lightly and inexpensively.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which a preferred embodiment of an automatic document feeder configured according to the present invention is mounted on an electrostatic copying machine.

FIG. 2 is a schematic sectional view of the automatic document feeder shown in FIG.

FIG. 3 is a sectional view showing a first embodiment of a transport belt mechanism provided in the automatic document transport apparatus shown in FIGS. 1 and 2;

FIG. 4 is an essential part perspective view showing a second embodiment of a transport belt mechanism provided in the automatic document transport apparatus shown in FIGS. 1 and 2;

FIG. 5 is a perspective view of a main part showing a third embodiment of a transport belt mechanism provided in the automatic document transport apparatus shown in FIGS. 1 and 2;

FIG. 6 is an essential part perspective view showing a fourth embodiment of a transport belt mechanism provided in the automatic document transport apparatus shown in FIGS. 1 and 2;

[Explanation of symbols]

 2: electrostatic copying machine 4: automatic document feeder 6: housing of electrostatic copying machine 8: transparent plate 10: document regulating member 18: document placing means 20: document discharge tray 22: document table 30: forward feed means 32 : Guide plate 34: forward feed roller 35: electric motor 36: pressurizing mechanism 362: rotating shaft of pressurizing mechanism 364: pressurizing plate of pressurizing mechanism 38: support substrate 40: paper feed roller 42: rotation of paper feed roller Shaft 44: cylindrical portion of paper feed roller 46: roller portion of paper feed roller 50: document separation mechanism 51: separation roller 60: front separation means 64: support plate of front separation means 66: front separation plate 70: transport belt mechanism 71: Support frame of the conveyor belt mechanism 72: Driving roller of the conveyor belt mechanism 73: Driven roller of the conveyor belt mechanism 74: Endless belt of the conveyor belt mechanism 75: Belt pressing member 751 of the conveyor belt mechanism : Pressing plate 752: pressing plate 753: pressing plate 754: pressing plate 76: document conveyance path 77: double-sided adhesive tape 80: document conveyance path 82: registration roller pair 90: document discharge means 92: document conveyance path 94: conveyance roller pair 96: discharge roller pair

Continued on the front page (72) Inventor Masuo Kawamoto 1-2-28 Tamazo, Chuo-ku, Osaka-shi Inside Mita Kogyo Co., Ltd. (72) Inventor Masahiro Sako 1-2-28 Tamatsuzo, Chuo-ku, Osaka-shi Mita Kogyo shares Company F term (reference) 2H076 BA22 BA47 BA48 3F049 AA02 BB07 BB11 BB12 DA05 LA02 LA05 LB02

Claims (6)

[Claims] 1. An automatic document feeder having a transport belt mechanism for transporting a document along a document transport path formed on a transparent plate of a document processing apparatus, comprising: a transport belt mechanism; a support frame; A driving roller and a driven roller disposed in parallel to the frame at intervals in the transport direction, an endless belt wound around the driving roller, the driven roller, and the support frame, the driving roller and the driven A belt pressing member disposed between the endless belt and the roller to press the endless belt toward the transparent plate. The belt pressing member is disposed in a width direction of the endless belt, and a document conveying area is provided. And a pressing plate attached to the bottom plate of the support frame body having a length corresponding to the pressing plate, the pressing plate having a curved portion protruding toward the endless belt side,
The automatic document feeder, wherein the curved portion presses the endless belt. 2. The pressing plate is made of an elastic sheet member, and both end portions of the endless belt in the moving direction are adhered to the lower surface of the bottom plate with a double-sided adhesive tape or an adhesive. The automatic document feeder according to claim 1. 3. The pressing plate is made of an elastic sheet member, and both end portions in the moving direction of the endless belt are engaged with a plurality of locking claws provided on the bottom plate. Automatic document feeder as described. 4. The pressing plate is formed of a plate material having elasticity, and both end portions in the moving direction of the endless belt are engaged with a plurality of locking claws provided on the bottom plate. Item 2. The automatic document feeder according to Item 1. 5. A plurality of supporting portions are provided at both sides of the pressing plate in the moving direction of the endless belt at intervals, and the supporting portions are engaged with the plurality of locking claws. The automatic document feeder according to claim 4, wherein: 6. The automatic document feeder according to claim 1, wherein the pressing plate is formed of a synthetic resin material, and both end portions of the endless belt in the moving direction are supported by the bottom plate via a spring member. .