Image forming apparatus with improved document feeder

An image forming apparatus has an automatic original feeder for conveying an original along a path to a transparent platen. This automatic original feeder conveys the original to a position where it lies between the platen and an original conveying device which is disposed on a frame which can cover the transparent platen. The frame is rotatably supported by a supporting member. This supporting member is attached movably up and down relative to the main body of the apparatus and it is elastically urged downward. This biases the original conveying device downwardly, so that the pressure applied to the original by the original conveying device is properly maintained, thereby ensuring reliable conveyance of the original. Clearances between the original conveying device and an original cover plate on the frame are covered with clearance covering members, thereby to prevent an outline of the original conveying device from appearing in a transferred image. The supporting member can be attached to the main body of the apparatus through an adapter member, thereby allowing a single model of automatic original feeder to be mounted on different types of image forming apparatuses. The original conveying device is reversible, the transparent platen has an inclined surface at its infeed/outfeed end, and the feeder has holding extensions which hold down the infeed end of the platen on opposite sides of the original's path.

BACKGROUND OF THE INVENTION 
The present invention relates to an image forming apparatus provided with 
an automatic original feeder for conveying an original with it being 
interposed between a transparent platen and original conveying means. 
Conventionally, there has been known an electrophotographic copying 
apparatus provided with an automatic original feeder for automatically 
conveying an original to a transparent platen. 
The above described automatic original feeder generally has a frame, 
original conveying means provided on this frame, and original feeding 
means for feeding an original to this original conveying means. 
The above described frame is pivotable between such a closed position as to 
cover the transparent platen and such an opened position as to expose the 
transparent platen. The original feeding means is adjacent to the above 
described frame, and it feeds originals to the original conveying means 
one at a time. The original conveying means conveys the original fed by 
the original feeding means to a required position on the transparent 
platen and conveys the original from the transparent platen to the upper 
surface of the frame after exposing the original to light while scanning 
is terminated (see, for example, Japanese Patent Laid-Open Gazette No. 
118551/1985). This original conveying means is constituted by an endless 
delivery belt mounted on almost the entire lower part of the frame. 
On the other hand, in order to simplify the structure of the 
electrophotographic copying apparatus, the applicant of the present 
invention has proposed a delivery roller type automatic original feeder 
(see Japanese Patent Application No. 61333/1988). This automatic original 
feeder uses as the document conveying means a delivery roller which is 
mounted on the lower part of a frame and can abut on the upper surface of 
a transparent platen, which conveys an original to and from the 
transparent platen with it being interposed between this delivery roller 
and one end of the original platen according to forward and reverse 
rotation of the delivery roller. 
However, in an electrophotographic copying apparatus of an intermediate 
degree or less, a frame is not a high strength frame made of steel or the 
like but of monocoque construction so as to simplify the structure and 
reduce the cost, so that the frame is liable to, for example, warped. 
Thus, this electrophotographic copying apparatus has the disadvantage in 
that an original can not be reliably conveyed because the pressure applied 
to the original by the original conveying means is changed due to, for 
example, the effect of the warping or the like and the variation in 
assembling precision. 
In order to eliminate the disadvantage, there has been known an 
electrophotographic copying apparatus for adjusting the above described 
pressure by providing a height adjusting mechanism for adjusting the 
height of a frame from a transparent platen. In this electrophotographic 
copying apparatus, a supporting portion of the frame is fixed to a 
vertical plate provided on the main body thereof by a bolt and a nut and a 
portion penetrated by the bolt in the vertical plate is a slot. The above 
described height adjusting mechanism is used for adjusting the position in 
which the supporting portion is attached to the vertical plate. 
Accordingly, the adjustment must be carried out while lifting the frame, 
which is not easy. In addition, one of the bolt and the nut is arranged 
inside of the frame. Thus, the adjustment must be carried out with the 
frame being opened, which is troublesome. 
Meanwhile, the above described delivery roller is arranged directly over 
the transparent platen at the time of conveying the original. Thus, the 
electrophotographic copying apparatus also has the disadvantage in that a 
good reproduced image can not be obtained because an outline or the like 
of the delivery roller is clearly copied on copy paper when the size of an 
original is so small that the delivery roller is forced out of the 
original in, for example, manually disposing the original or when an 
original permeable to light at the time of exposure to light such as a 
copy of a sheet for an OHP (Over Head Prejector) or a tracing paper is 
copied. 
Furthermore, the above described image forming apparatus is generally 
provided with an original discharge passage in a predetermined position 
between the frame and the delivery roller and adapted to convey the 
original fed from the original feeding means through an original conveying 
passage to the transparent platen by forward rotation of the delivery 
roller as well as to convey the original from the transparent platen to 
the upper surface of the frame by way of the original discharge passage by 
reverse rotation of the delivery roller after termination of exposing the 
original to light while scanning. 
Only an end of the above described transparent platen which is farther away 
from the original feeding means is pressurized to be fixed by a 
longitudinal fixing member. The reason is that it is difficult to convey 
the original from the transparent platen if an end of the transparent 
platen which is closer to the original feeding means is also fixed by the 
fixing member because the original is caught by the fixing member at the 
time of conveying the original from the transparent platen. In addition, 
the reason is that a guide member for introducing the original into the 
original discharge passage, which must be provided in the vicinity of the 
end of the transparent platen which is closer to the original feeding 
means, can not be provided in the end if the end is fixed by the above 
described fixing means. 
Thus, the above described image forming apparatus also has the disadvantage 
in that the original is copied with an image forming position being 
shifted irrespective of accurately setting the original to a mark on the 
transparent platen because the position of the transparent platen is 
shifted due to the vibration caused at the time of exposing the original 
to light while scanning and the time of opening and closing an original 
cover. In addition, it has the disadvantage in that the transparent platen 
is cracked by the vibration of the transparent platen itself. 
On the other hand, when the above described automatic original feeder is 
mounted on an image forming apparatus of a type of manually disposing an 
original on a transparent platen, a supporting member for rotatably 
supporting the above described frame is attached to a hole for attaching a 
conventional original cover on the upper surface of the main body thereof, 
thereby to mount the automatic original feeder to the main body of the 
image forming apparatus. 
The position of the above mentioned hole for attaching an original cove 
differs by the types of image forming apparatuses. Thus, an automatic 
original feeder of plural specification having different arrangement of a 
supporting member of a frame is necessary according to the position of a 
hole for attaching an original cover of each type, which brings the 
disadvantage of cost increase. 
SUMMARY OF THE INVENTION 
An object of the present invention is to provide an image forming apparatus 
capable of properly maintaining the pressure applied to an original by 
original conveying means, to ensure reliable conveyance of the original. 
Another object of the present invention is to prevent an outline of 
original conveying means from appearing in a transferred image. 
Still another object of the present invention is to surely prevent the 
movement, the vibration or the like of a transparent platen without 
increasing the burden of cost. 
A further object of the present invention is to make it possible to mount 
an automatic original feeder of a single specification on the main bodies 
of a plurality of types of image forming apparatuses to reduce cost. 
The above described objects can be achieved by providing an image forming 
apparatus provided with an automatic original feeder for conveying an 
original which is interposed between a transparent platen and at least one 
original conveying means on a frame which can cover platen the transparent 
platen, which comprises at least one supporting member attached movably up 
and down to the main body of the image forming apparatus and pivotally 
supports the frame and urging means for elastically urging this supporting 
member downward. 
Furthermore, the image forming apparatus provided with the automatic 
original feeder for conveying an original which is interposed between a 
transparent platen and at least one original conveying means on a frame 
which can cover the transparent platen may comprise at least one 
supporting member attached movably up and down to the main body of the 
image forming apparatus and rotatably supporting the frame, a shaft 
provided on this supporting member and having a screw portion fed through 
a through-hole of the main body of the image forming apparatus, and a nut 
threaded into the screw portion of this shaft for adjusting the height of 
the frame from the transparent platen. 
Additionally, the image forming apparatus provided with the automatic 
original feeder for conveying an original with interposed between a 
transparent platen and at least one original conveying means on a frame 
which can cover the transparent platen may comprise an original cover 
plate provided on the frame and opposable to the transparent platen and at 
least one clearance covering member having almost the same color tone as 
those of the original conveying means and the original cover plate for 
covering a clearance between the original conveying means and the original 
cover plate. 
The above described clearance covering member may be a body having a lot of 
fine flexible elements. 
The above described body may be a pile material. 
The above described clearance covering member may be synthetic paper 
affixed to the original cover plate. 
The image forming apparatus is preferably constructed such that the above 
described original conveying means can convey an original from the 
transparent platen in the direction opposite to such a direction as to 
convey the original to the transparent platen, the above described 
automatic original feeder has original feeding means for feeding originals 
to the original conveying means one at a time, and the original feeding 
means has a pair of holding extensions for holding down the transparent 
platen in positions on both sides of an original conveying passage which 
is interposed therebetween. 
Furthermore, the image forming apparatus provided with an automatic 
original feeder for conveying an original interposed between a transparent 
platen and at least one original conveying means on a frame which can 
cover the transparent platen may comprise an adapter member provided on an 
upper surface of the main body of the image forming apparatus and at least 
one supporting member attached movably up and down to this adapter member 
and rotatably supporting the frame. 
In the image forming apparatus constructed according to the present 
invention, the above described supporting member for supporting the frame 
is held downward by an elastic member. Thus, when the frame is, for 
example, warped, the frame is held downward, thereby to properly maintain 
the pressure applied to the original by the original conveying means. 
When a nut for adjusting the height of the frame from the transparent 
platen is threaded into the screw portion of the shaft provided on the 
supporting member, the above described pressure can be adjusted by 
performing a rotating operation of the nut to directly move the shaft up 
and down. 
When the above described clearance is covered with at least one clearance 
covering member having almost the same color tone as those of the original 
conveying means and the original cover plate, an outline of the original 
conveying means can be prevented from being transferred to copy paper. 
When the above described clearance covering member is a body of fine 
flexible elements, the body does not prevent an operation of the original 
conveying means. 
When the above described body is a pile material, the piles need not be 
planted one at a time, so that the pile material can be easily replaced 
with a new one if the piles become dirty. 
When the above described clearance covering member is the above described 
synthetic paper, the synthetic paper is in contact with the original 
conveying means while following the same. Accordingly, the synthetic paper 
does not prevent the operation of the original conveying means and the 
synthetic paper can be easily replaced with a new one. 
When the above described original feeding means has the above described 
pair of holding extensions, the shift in the position of the transparent 
platen caused by the vibration of the transparent platen can be prevented 
without preventing the original from being conveyed from the transparent 
platen. In addition, it is simultaneously possible to mount the original 
feeding means on the main body of the image forming apparatus and to fix 
the transparent platen. Accordingly, the image forming apparatus thus 
constructed has a good operating performance and is favorable in cost. 
When a supporting member for supporting the above mentioned frame is 
attached to an adapter member provided on an upper surface of the main 
body of the image forming apparatus, an automatic original feeder of a 
single specification can be mounted on the main bodies of a plurality of 
types of image forming apparatuses by changing the adapter member 
corresponding to the main body of the image forming apparatus to which the 
automatic original feeder is attached. Accordingly, cost reduction due to 
quantity production can be achieved.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The embodiments will be described in detail in conjunction with the 
accompanying drawings. 
Referring to FIG. 3, an automatic original feeder 2 is attached to an upper 
surface 100 of a housing 10 in the main body of an electrophotographic 
copying apparatus 1. This automatic original feeder 2 has a frame 3, 
delivery rollers 41, 42 and 43 attached to this frame 3, and original 
feeding means 5 provided adjacent to the frame 3 for feeding an original 
to the delivery roller 41, 42 and 43. 
The delivery rollers 41, 42 and 43 are the document-engaging portions of an 
original conveying means which moves original documents which are fed onto 
a transparent platen 11 by the original means feeding means 5. The platen 
is made of transparent contact glass and it is disposed on the upper 
surface 100 of the above described housing 10. Through-holes 12a and 12b 
are provided in a rear edge portion 100b of the upper surface 100 and a 
metal plate 14 is attached to a front edge portion 100a of the upper 
surface 100. 
The above described frame 3 is attached to the housing 10 turnably between 
such a closed position as to cover the transparent planten 11 and such an 
opened position as to expose the transparent platen 11 and movably up and 
down by a pair of hinge units 6a and 6b. The frame 3 is made of resins or 
the like and has an original cover plate 31 in white or the like attached 
to its lower surface. Notch portions 32a, 32b and 32c are provided in one 
side 31a of this original cover plate 31. Recessed portions 33a and 33b on 
which the hinge units 6a and 6b are respectively disposed are provided on 
a lower surface of a rear edge portion 3b of the frame 3 in the closed 
position. A magnet 34, a pair of positioning members 35a and 35b and a 
recessed portion 36 are provided on a lower surface of a front edge 
portion 3a of the frame 3. 
The magnet 34 adheres to the metal plate 14 on the upper surface 100 of the 
housing 10 with the frame 3 being in the closed position, to hold the 
closed state of the frame 3 by a predetermined holding force. The 
positioning members 35a and 35b abut on the upper surface 100 of the 
housing 10 to receive a part of the load of the frame 3 with the frame 3 
being in the closed position as well as determine the height of the front 
edge portion 3a of the frame 3 from the transparent platen 11. The concave 
portion 36 is used when the front edge portion 3a of the frame 3 is lifted 
by inserting a finger to rotate the frame 3 such that the position thereof 
is changed from the closed position to the opened position. 
Referring to FIGS. 1 to 2, the above described hinge unit 6a comprises a 
pin 60, and an upper member 61 and a lower member 62 rotatably connected 
to each other by the pin 60. The upper member 61 is formed of a channel 
material 63 opened downward which is adhered to the concave portion 33a of 
the frame 3. The lower member 62 has a shaft 64 extending downward 
provided on a lower surface 63a of the channel material 63 opened upward. 
This shaft 64 penetrates slidably up and down the through-hole 12a of the 
housing 10. The above described hinge unit 6b has the same structure as 
that of the hinge unit 6a. 
The through-hole 12a is formed of a pipe material 15 adhered to the housing 
10 in the main body of the electrophotographic copying apparatus 1, as 
shown in FIG. 1. The through-hole 12b has the same structure as that of 
the through-hole 12a. A spring washer 65 is removably fit to a groove 
portion 64b in an end 64a of the shaft 64. A compression coil spring 7 
penetrated by the shaft 64 is movably fit between an upper surface 65a of 
the spring washer 65 and a lower surface 15a of the pipe material 15. The 
shaft 64 is urged downward by the compression coil spring 7, so that the 
hinge unit 6b is urged downward. Similarly, the hinge 6b is urged 
downward. 
A bolt 8 is threaded into the channel material 63 of the hinge unit 6a with 
a top 80 thereof abutting on the upper surface 100 of the housing 10. The 
bolt 8 regulates the downward movement of the hinge unit 6a urged downward 
by the compression coil spring 7. The vertical position of the hinge unit 
6a is adjusted according to the amount of projection of the bolt 8 from 
the lower surface 63a of the channel material 63. Similarly, the vertical 
position of the hinge unit 6b is adjusted. The minimum height of the frame 
3 from the transparent platen 11 is adjusted by the adjustment of the 
vertical position of each of the hinge units 6a and 6b. The height of the 
frame 3 from the transparent platen 11 is adjusted such that the original 
cover plate 31 is in an almost horizontal state with the frame 3 being in 
the closed position and a clearance of approximately 1 mm occurs between 
the original cover plate 31 and the transparent platen 11. 
Meanwhile, the above described hinge units 6a and 6b are respectively 
provided with opened state holding mechanisms (not shown) each using a 
link mechanism, a tension spring or the like so as to maintain the frame 3 
in the opened state. 
The hinge units 6a and 6b rotatably supporting the frame 3 are supported 
movably up and down in the housing 10 in the main body of the 
electrophotographic copying apparatus 1, thereby to make it possible to 
cope with a thick original such as a book. 
The above described hinge units 6a and 6b are respectively urged downward 
by the compression coil spring 7. Thus, the frame 3 is held downward when 
the frame 3 is, for example, warped. Thus, the pressure applied to the 
original by the delivery rollers 41, 42 and 43 can be properly maintained 
so that the original can be reliably conveyed. Moreover, in the above 
described embodiment, a floating force is produced for the frame 3 by the 
upward contact reaction which a transfer gear 38(FIG. 4) receives from a 
driving transfer gear 27 while driving the automatic original feeder 2. 
The pressure applied to the original by the delivery rollers 41, 42 and 43 
can be properly maintained against this floating force exerted by drive 
gear 27, so that the original can be reliably conveyed. 
Since the hinge units 6a and 6b are respectively provided with bolts 8 
capable of adjusting the minimum height of the frame 3 from the 
transparent platen 11, the height of the frame 3 from the transparent 
platen 11 at the time of conveying the original can be properly maintained 
by adjusting the bolts 8, so that the originals can be further reliably 
conveyed. In addition, since the bolts 8 are exposed to the outside, the 
above described adjustment is easily carried out. 
Referring to FIGS. 3 and 5, the above described original feeding means 5 is 
attached to a slide edge portion 100c of the upper surface 100 of the 
housing 10 by connecting means such as a bolt. This original feeding means 
5 has an original table 50, a first drive roller 51, a second drive roller 
52, a reversing roller 53, a guide plate 54, an upper cover 55, a lower 
cover 56, an original set detector 57, an original feeding detector 58, 
and feeding preventing means 59. 
The above described original table 50 is provided in an inclined manner. A 
sheet-like original P is disposed on this original table 50. The first 
drive roller 51 abuts on the upper surface of the sheet-like original P 
when required, to take out originals A in the direction of feeding 
(rightward in FIG. 5) along the original table 50 one at a time. The 
second drive roller 52 feeds the original A taken out by the first drive 
roller 51 to the delivery rollers 41, 42 and 43. The reversing roller 53 
rotates in synchronization with the second drive roller 52, to prevent two 
or more originals from being simultaneously fed. 
The above described guide plate 54 is provided on the extension of the 
original table 50. A lower end 54a of the guide plate 54 is exposed from 
an opening 20 for feeding the original, to guide the fed original A to the 
direction of feeding. The upper cover 55 covers an upper part of the first 
drive roller 51, the second drive roller 52 and the reversing roller 53. 
The lower cover 56 is formed in a bottom portion of the original feeding 
means 5 and directly attached to the housing 10. The original set detector 
57 detects setting of the sheet-like original P on the original table 50 
by upsetting of a bar 57a. The original feeding detector 58 detects 
feeding of the original by upsetting of a bar 58a. The feeding preventing 
means 59 prevents the original from being fed when it need not be fed. 
The original feeding means 5 exposes the driving transfer gear 27 with it 
being adjacent to the guide plate 54, as shown in FIG. 3. 
Referring to FIGS. 3 and 12, an end 11b of the transparent platen 11 which 
is farther away from the original feeding means 5, along with the side 
edge portion 100d of the upper surface 100 of the housing 10, is held down 
by a longitudinal holding member 22. This holding member 22 is fixed to a 
supporting plate 23 provided on the lower surface of the housing 10 by 
fixing means 24a and 24b such as a bolt. 
An inclined surface 11c by chamfering is formed in an end 11a of the 
transparent platen 11 which is closer to the original feeding means 5. 
This inclined surface 11c performs the function of facilitating the 
introduction of the original conveyed from the original feeding means 5 
into the transparent platen 11. An end of a guide member 37 (FIG. 5) 
attached to a predetermined position of the frame 3 is in contact with 
this inclined surface 11 c. 
This guide member 37 is formed of, for example, a film of flexible 
synthetic resins such as polyester approximately 0.075 mm thick and picks 
up an original which has been exposed to light while being scanned in 
conveying the original from the transparent platen 11. A cushioning 
material 26 having elasticity such as rubber or the like is interposed 
between the end 11a of the transparent platen 11 and a supporting plate 25 
provided below the housing 10. 
A hanging portion 54b for holding a guide plate 54 at a predetermined 
height is formed in an end 54a of the guide plate 54, and a pair of 
holding extensions 21a and 21b for holding down the transparent platen 11 
to fix the same is formed therein with they being projected in the 
horizontal direction. The holding convex portions 21a and 21b are provided 
in positions on both sides of the original conveying passage W (FIG. 3) 
which is interposed therebetween, to make it possible to convey the 
original to and from the transparent platen 11 without obstructing 
movement of the original. 
Since the distal end 11b of the transparent platen 11 is held down by the 
holding member 22 and the infeed/outfeed end 11a of the transparent platen 
11 is held down by the holding extensions 21a and 21b, the shift of the 
position of the transparent platen 11 caused by vibrations is prevented. 
In addition, since the original feeding means 5 is provided with the 
holding extensions 21a and 21b, the transparent platen 11 can be fixed by 
only attaching the original feeding means 5 to the housing 10. 
Accordingly, the assembling work of the transparent platen 11 and the 
automatic original feeder 2 can be quickly and simply performed, which is 
preferable in cost. 
Meanwhile, as shown in FIG. 13, the pair of holding extensions 21a and 21b 
can be also formed in a forward end 56a of the lower cover 56 of the 
original feeding means 5. In this case, the transparent platen 11 can be 
prevented from being damaged by the metallic lower cover 56 by interposing 
an elastic body 28 such as rubber between each of the above described 
holding extensions 21a and 21b and the end 11a of the transparent platen 
11. 
The delivery rollers 41, 42 and 43 are respectively exposed from the above 
described notch portions 32a, 32b and 32c. The delivery rollers 41, 42 and 
43 convey the original fed from the original feeding means 5 to a 
predetermined position on the transparent platen 11 by forward rotation 
(counterclockwise rotation in FIG. 5) as well as discharges the original 
which has been exposed to light while being scanned from an original 
discharge port 71 to an discharge tray 72 provided on an upper surface of 
the frame 3 by reverse rotation (clockwise direction in FIG. 5) (see FIG. 
7). 
As shown in FIG. 8, the delivery rollers 41, 42 and 43 are arranged 
integrally rotatably around a single rotation axis 44. The delivery 
rollers 41, 42 and 43 convey the original such that at least a rear end of 
the original is interposed between the delivery rollers 41, 42 and 43 and 
the transparent platen 11 so as to convey the original from the 
transparent platen 11 at the time of reverse rotation (see FIG. 6). 
As shown in FIG. 17, the original conveying means 3 may have a delivery 
belt 42a which is driven by the driving drum 42 to convey an original on 
the transparent platen 11. 
A plurality of guide ribs 73 for introducing the original to the original 
discharge port 71 hang in an internal upper portion of the frame 3 with 
suitable spacing in the crosswise direction. The original introduced by 
the guide ribs 73 is discharged from port 71 with it being interposed 
between the delivery roller 42 in the center as well as a pair of guide 
plates 75 and a driven roller 76 (see FIG. 7). 
Referring to FIGS. 3 and 4, the transfer gear 38 connected to the rotation 
axis 44 of each of the delivery rollers 41, 42 and 43 is accommodated in a 
recessed portion 30. The transfer gear 38 engages with the above described 
driving transfer gear 27 entering the recess 30 from below with the frame 
being in the closed state. The driving transfer gear 27 and the transfer 
gear 38 engage with each other, so that the delivery rollers 41, 42 and 43 
are operated simultaneously with the original feeding means 5. 
Referring to FIGS. 5 and 8, clearances S between the delivery rollers 41, 
42 and 43 and the original cover plate 31 are blocked with annular pile 
materials 45 and a pile materials 46 each having a lot of feathers J. The 
annular pile materials 45 are respectively attached to a pair of side end 
surfaces 41a and 4b of the delivery roller 41, a pair of side end surfaces 
42a and 42b of the delivery roller 42, and a pair of side end surfaces 43a 
and 43b of the delivery roller 43 (see FIG. 8). The pile materail 46 is 
attached to the original cover plate 31 (see FIG. 5). 
The annular pile materials 45 ans the pile material 46 have almost the same 
color tone as those of the delivery rollers 41, 42 and 43 and the original 
cover plate 31. In general, the delivery rollers 41, 42 and 43 and the 
original cover plate 31 are both white in the electrophotographic copying 
apparatus or the like. Thus, the annular pile matrials 45 and the pile 
material 46 are most preferably white but may be light-colored such as 
ligt yellow which does not affect a reproduced image. The reproduction of 
the shades of the clearances S on the copy paper can be prevented by the 
annular pile materials 45 and the pile material 46. 
Any of the above described annular pile materials 45 and the pile material 
46 is a fabric made of fiber such as nylon and rayon, which has an 
adhesive layer on the reverse side thereof. Any of the surfaces of the 
annylar pile materials 45 and the pile material 46 is densely covered with 
a lot of fine flexible elements J comprising a pile and a loop. The 
clearances S can be blocked by only affixing the annular pile material 45 
and the pile material 46 to the delivery rollers 41, 42 and 43 and 
original cover plate 31. Accordingly, the annular pile materials 45 and 
the pile material 46 have the advantage of not requiring time or labor to 
plant the elements J one at a time as welll as of being able to be easily 
replaced when the flexible elements J become dirty. In addition, the 
rotation load of each of the delivery rollers 41, 42 and 43 is not 
practically increased and the durability of the annular pile materials 45 
and the pile material 46 themselves is good because the above described 
elements J are so flexible that they do not prevent rotation of each of 
the delivery rollers 41, 42 and 43. 
Meanwhile, as shown in FIG. 9, pile materials 47 can be respectively 
attached to pairs of folded portions 32d and 32e, 32f, and 32g, and 32h 
and 32i formed by folding upward surfaces of the notch portions 32a, 32b 
and 32c of the original cover plate 31. 
Other bodies with fine flexible elements such as felt and velvet can be 
used in place of the above described annular pile materials 45, pile 
material 46 and pile materials 47. This body must be so fine, flexible and 
dense that it does not prevent rotation of each of the delivery rollers 
41, 42 and 43 and can considerably block the clearances S. In addition, 
the body can be also formed by a direct planting method such as a static 
planting method. The attachment of the annular pile materials 45, the pile 
material 46 and the pile materials 47 is not limited to affixing with the 
above described adhesive. 
Meanwhile, the above described clearances S can be covered with U-shaped 
synthetic paper 48 affixed to the lower surface of the original cover 
plate 31 with adhesive, as shown in FIGS. 10 and 11. An internal edge 48a 
of the synthetic paper 48 is brought into contact with a cylindrical 
surface 42c and both side end surface 41a and 41b of the delivery roller 
41. The clearance between the delivery roller 42 and the original cover 
plate 31 and the clearance between the delivery roller 43 and the original 
cover plate 31 are covered with the synthetic paper in the same manner. A 
tongue member 48c deeply cut by a cutting line 48b is formed in the 
synthetic paper 48, the tongue member 48c greatly following forward and 
reverse rotation of each of the delivery rollers 41, 42 and 43. 
The sysnthetic paper 48 is generally one mainly made of synthetic resins 
and having various properties of a natural paper added thereto. 
This synthetic paper 48 preferably has the following properties in the 
Japanese Industrial Standards (merely referred to as JIS hereinafter). 
Thickness: about 40.about.100 .mu.m (JIS, P-8118) 
Density: about 0.7 .about.1 g/cm.sup.3 (JIS, P-8118) 
Whiteness: 90% or more (JIS, in conformity to L-1015 ) 
Opacity: 70% or more (JIS, P-8138) 
Glossiness: about 5.about.20% (JIS, P-8142) 
Tensile Strength (MD): 2 kg/15 mm or more (JIS, P-8113) (CD): 7 kg/15 mm or 
more (JIS, P-8113) 
Tensile Expansion (MD): 80% or more (JIS, P-8132) (CD): 25% or more (JIS, 
P-8132) 
Tearing Strength (MD): 15 g or more (JIS, P-8116) (CD): 10 g or more (JIS, 
p-8116) 
Hardness (MD): 10 (S valve) or more (JIS, P-8143) (CD): 15 (S valve) or 
more (JIS, P-8143) 
Bursting: 3 kg/cm.sup.3 or more (JIS, P-8112) 
Folding Endurance: 10.sup.4 times (JIS, P-8115) 
Furthermore, the properties required for the synthetic paper 48 includes 
the property of being opaque and having almost the same color tone (white, 
light yellow or the like) as those of the lower surfaces of the delivery 
rollers 41, 42 and 43 and the original cover plate 31, the property of 
having durability such as abrasion resistance with respect to the contact 
with cylindrical surfaces of the delivery rollers 41, 42 and 43 which 
rotate in forward and reverse directions, the original to be conveyed, or 
the like, and the property of having little effect on the cylindrical 
surface of the delivery rollers 41, 42 and 43. 
The synthetic paper 48 satisfying the required properties is, for example, 
"YUPO" made by Ojiyukagouseishi Corp. YUPO is mainly made of polypropylene 
resins, at least one surface of which is a sheet-like layer. YUPO of an 
FPG grade having high opacity, for example, the 40th to 110th YUPO (40 to 
110 .mu.m thick) and particularly, the 60th to 95th YUPO (60 to 95 .mu.m 
thick) is preferably employed. 
When the clearance S are covered with this synthetic paper 48, reproduction 
of outlines or the like of the delivery rollers 41, 42 and 43 on the copy 
paper can be prevented by the synthetic paper 48. In addition, the 
synthetic paper 48 can satisfactorily follow forward and reverse rotation 
of each of the delivery rollers 41, 42 and 43. Accordingly, adverse 
effects to the delivery rollers 41, 42 and 43 suc as the increase in 
rotation load of each of the delivery rollers 41, 42 and 43 and damage to 
the delivery rollers 41, 42 and 43 can be reduced as much as possible by 
the synthetic paper 48 as well as the durability of the synthetic paper 48 
itself can be improved. 
Furthermore, the above described following characteristic are further 
increased by the tongue member 48c. Thus, the durability of the synthetic 
paper 48 is further improve and damage caused by the synthetic paper 48 to 
the delivery rollers 41, 42 and 43 can be more effectively prevented by 
the tongue member 48. Additionally, since the synthetic paper 48 is 
affixed, replacement thereof is easy. The replacement can be performed 
without removing the delivery rollers 41, 42 and 43, which is further 
easy. In addition, the synthetic paper 48 is not easily soiled. If it 
becomes soiled, it can be simply cleaned. Accordingly, the above described 
replacement need not be frequently performed, which does not take a lot of 
time or labor. 
The following comparing tests are carried out with respect to the above 
described durability and the effects to the delivery rollers 41, 42 and 43 
by continuously feeding sheets of paper to the automatic original feeder 2 
using copy paper, a polyester film (Mylar, 50 .mu.m thick), urethane 
rubber, and the above described YUPO as the synthetc paper 48. 
As a result, the following have become clear. The above described copy 
paper has the disadvantage in durability because it is torn when 
approximately 5000 sheets of paper are fed. The polyester film causes 
stripping on the cylindrical surfaces of the delivery rollers 41, 42 and 
43, so that adverse effects to the delivery rollers 41, 42 and 43, are 
large. The urethane rubber causes stripping on the cylindrical surfaces of 
the delivery rollers 41, 42 and 43 when approximately 1000 sheet of paper 
are fed because contact resistance between the urethane rubber and each of 
the delivery rollers 41, 42 and 43 is large due to the impossibility to 
decrease the thickness of the urethane rubber, so that adverse effects to 
the delivery rollers 41, 42 and 43 are very large. The above described 
YUPO does not change if 20000 to 30000 or more sheets of paper are fed and 
does not cause stripping on the cylindrical surfaces of the delivery 
rollers 41, 42 and 43. Accordingly, it is found that the YUPO is the most 
suitable for use as the synthetic paper 48. 
FIGS. 14 to 16 illustrate a main part of an image forming apparatus in 
which the height of a frame 3 from a transparent platen 11 can be 
adjusted. An adapted member 9 comprising a pair of attaching means 9a and 
9b and a connecting portion 98 is disposed on an upper surface 100 of a 
housing 10 in the main body of an electrophotographic copying apparatus 1, 
the frame 3 in an automatic orignal feeder 2 being attached to the main 
body of the electrophotographic copying apparatus 1 through this adaptor 
member 9. Hinge units 6a and 6b are respectively supported by the 
attaching means 9a and 9b, and the frame 3 in the automatic original 
feeder 2 is rotatably supported by the hinge units 6a and 6b. 
The attaching means 9a and 9b have the same structure, which are arranged 
with predetermined spacing along a rear edge portion 11d of the 
transparent platen 11. The attaching means 9a has a pair of upper member 
91 and lower member 92 having a U-shaped cross section which are 
vertically opposed to each other. The upper member 91 and the lower member 
92 are respectively provided with vertical through-holes 93 and 94. A 
flange portion 91a extends in a front edge of the upper member 91. Flange 
portions 92a and 92b respectively extend in a front edge and a rear edge 
of the lower member 92. The upper member 91 and the lower member 92 are 
combined with each other with the flange portion 91a of the upper member 
91 being in close contact with the flange protion 92a of the lower member 
92 and a rear edge 91b of the upper member 91 being in close contact with 
the flange portion 92b of the lower member 92. 
Furthermore, the lower member 92 of the attaching means 9a and the lower 
member 92 of the attaching means 9b are integrally connected to each other 
by a connecting portion 98. The connecting portion 98 is provided with a 
pair of through-holes 98a and 98b corresponding to a pair of tapped holes 
17a and 17b for attaching an original-holding cover provided on the upper 
surface 100 of the housing 10. Screws 99a and 99b fed through the screw 
through-holes 98a and 98b are respectively threaded into the tapped hols 
17a and 17b, so that the connecting portion 98 is secured to the upper 
surface 100 of the housing 10. 
Furthermore, the connecting portion 98 is provided with a pair of screw 
through-holes 98c and 98d corresponding to a pair of tapped holes for 
attaching an original-holding cover in the main body of another type of 
electrophotographic copying apparatus. Thus, one type of automatic 
original feeder 2 can be attached to the main bodies of the two types of 
electrophotographic copying apparatuses. Accordingly, cost reduction due 
to quantity production can be achieved. The connecting portion 8 may be 
provided with three or more pairs of screw through-holes, to make it 
possible to cope with three or more types of electrophotographic copying 
apparatuses. Since the adapter member 9 is attached to the upper surface 
100 of the housing 10, the attaching work is easy. Rubber 16 of suitable 
thickness and hardness is disposed between a lower surface of the lower 
member 92 and the upper surface 100 of the housing 10. The rubber 16 
allows the impact or the like at the time of the opening and closing of 
the frames to be absorbed. 
The hinge unit 6a differs from the hinge unit 6a shown in FIG. 1 in that a 
screw portion 64c is provided in an upper part of a shaft 64 and a 
circumferential groove portion 64d is provided in the central portion of 
the shaft 64. The shaft 64 is fed through the through-hole 93 of the upper 
member 91 and the through-hole 94 of the lower member 94, which is 
supported movably up and down by the through-holes 93 and 94. A spring 
washer 95 (see FIG. 15) having an E-like ring portion 95b made of resins 
or the like is removably fitted to the grooved portion 64d of the shaft 
64. A compression flat spring 7 is movably fitted between the spring 
washer 95 of the shaft 64 and the upper member 91. The shaft 64 is urged 
downward by this compression flat spring 7, so that the hinge unit 6a is 
urged downward. 
The above described spring washer 95 exposes a holding portion 95a to the 
outside of the frame 3 through the through-hole 39 of the frame 3 and a 
through-hole 96 of the upper member 91. The spring washer 95 can be easily 
removed from the shaft 64 from outside by pulling this holding portion 
95a. In addition, a stopper 97 for regulating the upward movement of the 
shaft 64 at a predetermined height is removably fitted to a groove portion 
64b of the shaft 64. This stopper 97 has the same structure as that of the 
above described spring washer 95, which can be easily removed from 
outside. 
According to the present embodiment, the same effect as that according to 
the embodiment shown in FIG. 1 as well as the following effect are 
achieved. The screw portion 64cof the shaft 64 is threaded into a nut 90. 
This nut 90 abuts on an upper surface 91c of the upper member 91. Thus, 
the minimum height of the frame 3 from the original platen 11 can be 
adjusted by performing an rotating operation of the nut 90 to move the 
shaft 64 up and down. 
Since the nut 90 can directly move the shaft 64 up and down, the operating 
force for rotating the nut 90 may be small. In addition, since the above 
described rotating operation can be performed from outside with the frame 
3 being closed, the adjustment can be easily performed. 
Additionally, since the hinge units 6a and 6b are respectively supported by 
the attaching means 9a and 9b disposed on the upper surface 100 of the 
housing 10, attaching portions of the hinge units 6a and 6b can be exposed 
to the outside of the housing 10 in the main body of the 
electrophotographic copying apparats 1. The attaching portions of the 
above described hinge units 6a and 6b thus exposed to the outside are 
removed, thereby to allow the automatic original feeder 2 to be easily 
removed. In addition, the spring washer 95 and the stopper 97 can be 
removed from the outside of the frame 3, thereby to allow the automatic 
original feeder 2 to be more easily removed. 
Meanwhile, in the above described each embodiment, only the hinge unit 6a 
close to the delivery rollers 41, 42 and 43 can be urged downward by the 
compression coil spring 7 or the compression plate spring 7. 
In this case, as described above, attaching portions of the delivery 
rollers 41, 42 and 43 of the frame 3 are urged upward by the upward urged 
force which a transfer gear 38 receives from a driving transfer gear 27. 
However, against this urged force, the delivery rollers 41, 42 and 43 can 
be held downward by urging the above described hinge unit 6a downward. 
Thus, the pressure applied to the original by the delivery rollers 41, 42 
and 43 can be properly maintained, so that the original can be reliably 
conveyed. 
In the embodiment shown in FIG. 1, the pressure applied to the original by 
the delivery roller 41, 42 and 43 can be adjusted to be proper by only 
adjusting the height using the bolt 8 without providing the compression 
coil spring 7. Similarly, in the embodiment shown in FIG. 14, the pressure 
applied to the original by the delivery rollers 41, 42 and 43 can be 
adjusted to be proper by only adjusting the height using the nut 90 
without providing the compression plate spring 7. Additionally, the image 
forming apparatus according to the present invention is not limited to the 
above described embodiments. Various modifications in design can be made 
within the range in which the gist of the present invention is not 
changed. For example, only one hinge unit or three or more hinge units can 
be provided. Another known hinge unit structure can be used as a structure 
of the hinge unit. A known supporting mechanism performing the same 
function as that of the hinge unit can be used in place of the hinge unit. 
Moreover, a delivery belt of almost the same size as that of the delivery 
roller can be used in place of the delivery roller.