Automatic document conveyer

An automatic document conveyer comprising a moving frame turnably mounted on a machine housing via a hinge mechanism and a conveyer belt mechanism mounted on the moving frame. The conveyer belt mechanism includes a support frame, a drive roller and a driven roller arranged in the support frame, and a conveyer belt wrapped round the drive roller and the driven roller. The support frame of the conveyer belt mechanism is so supported as to be moved by a predetermined amount toward the side opposite to the hinge mechanism while the end of the conveyer belt on the side of the hinge mechanism reaches to the closed position after having come in contact with the transparent plate at the time when the moving frame is turned toward the closed position.

FIELD OF THE INVENTION 
The present invention relates to an automatic document conveyer employed by 
document processors such as electrostatic copier, facsimile, image reader 
and the like. 
DESCRIPTION OF THE PRIOR ART 
With a recent trend toward carrying out the copying processing of a copier 
at a high speed and automatically, there is practically used an automatic 
document conveyer which successively and automatically feeds plural pieces 
of documents to a document set position on the upper surface of a 
transparent plate. Such an automatic document conveyer which successively 
and automatically feeds plural pieces of documents is widely used in the 
document processors such as facsimiles and document readers, too. The 
automatic document conveyer of this type includes a moving frame that is 
arranged to move between a closed position where it covers a transparent 
plate arranged on the upper surface of a machine housing and an open 
position where it permits the transparent plate to be exposed, and a 
conveyer belt mechanism which conveys the document along the document 
conveying passage formed on the transparent plate when the moving frame is 
brought to the closed position. The conveyer belt mechanism includes a 
support frame, a drive roller and a driven roller arranged in the support 
frame, apart from each other, in parallel in the direction of conveyance, 
and an endless conveyer belt wrapped round the drive roller and the driven 
roller. The moving frame is turnably mounted on the upper surface of the 
machine housing via a hinge mechanism, and the conveyer belt mechanism is 
mounted on the moving frame. The thus constituted automatic document 
conveyer is considerably heavy and requires a considerably large operation 
force for turning it from the closed position to the open position. To 
reduce this force, there has generally been employed a so-called lift-type 
hinge mechanism equipped with a spring member that exerts force for 
lifting the moving frame toward the opening direction at all times. 
In the automatic document conveyer equipped with the above-mentioned 
lift-type hinge mechanism, however, the moving frame is pushed toward the 
open position by utilizing the repulsive force of the spring and, hence, 
the fulcrum of the hinge is inevitably located at a position higher than 
the upper surface of the machine housing, i.e., higher than the upper 
surface of the transparent plate. When the fulcrum of the hinge or the 
fulcrum of turn of the moving frame locates at a position higher than the 
upper surface of the transparent plate, the position of contact with the 
transparent plate is displaced toward the side of the hinge mechanism 
while the conveyer belt of the conveyer belt mechanism mounted on the 
moving frame turns up to the closed position after it has come in contact 
with the transparent plate. When the automatic document conveyer is opened 
and the document is set by hand on the transparent plate, therefore, the 
document is shifted toward the side of the hinge mechanism when the 
automatic document conveyer is brought to the closed position; i.e., the 
document is deviated from the position at which it was set. In a copier of 
the type in which the document is set with its edge at one end to be 
brought in contact with the document instruction plate disposed on the 
side of the hinge mechanism (rear side), therefore, this deviation causes 
the document to be deflected and floated, producing a band-like shade on 
the image. 
SUMMARY OF THE INVENTION 
The object of the present invention is to provide an automatic document 
conveyer that prevents the position of the document from being deviated 
when the document is set by hand on the transparent plate. 
In order to accomplish the above-mentioned object according to the present 
invention, there is provided an automatic document conveyer comprising a 
moving frame arranged to move between a closed position where it covers a 
transparent plate arranged on the upper surface of a machine housing and 
an open position where it permits the transparent plate to be exposed, and 
a conveyer belt mechanism which conveys the document when said moving 
frame is brought to the closed position, said moving frame being turnably 
mounted on said machine housing via a hinge mechanism; wherein 
said conveyer belt mechanism includes a support frame, a drive roller and a 
driven roller arranged apart from each other in said support frame in 
parallel in the direction of conveying the document, and a conveyer belt 
wrapped round said drive roller and said driven roller, said conveyer belt 
mechanism being supported on said moving frame by a first support means 
that supports said support frame on the side of said hinge mechanism and 
by a second support means that supports said support frame at an end on 
the side opposite to said hinge mechanism; 
said first support means moves said conveyer belt mechanism by a 
predetermined amount toward the side opposite to said hinge mechanism 
while the end of said conveyer belt on the side of said hinge mechanism 
reaches to said closed position after having come in contact with said 
transparent plate, at the time when said moving frame is turned toward 
said closed position; and 
said second support means permits the motion of said conveyer belt 
mechanism. 
The first support means includes first support members mounted on said 
support frame and having pin-insertion holes, second support members 
mounted on said moving frame and having guide holes, and support pins 
arranged by being inserted in the pin-insertion holes of the first support 
members and in the guide holes in the second support members, the guide 
holes having a shape elongated in the up-and-down direction and being 
inclined toward the side opposite to the hinge mechanism from the lower 
side toward the upper side. 
The second support means supports the support frame on the moving frame, 
with a predetermined amount of suspension so as to allow the conveyer belt 
to come in contact with the transparent plate in parallel therewith when 
the moving frame is turned toward the closed position. 
Other features of the present invention will become obvious from the 
following description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Preferred embodiments of the automatic document conveyer constituted 
according to the present invention will now be described in detail with 
reference to the accompanying drawings. 
FIGS. 1, 2 and 3 illustrate an upper end portion of an electrostatic copier 
2 and an automatic document conveyer 3 mounted thereon. The electrostatic 
copier 2 has a housing 4. A transparent plate 5 which may be a glass plate 
is mounted on the upper surface of the housing 4. A document restriction 
member 6 is disposed on one side of the transparent plate 5 (left side in 
FIG. 3) to determine a reference position for setting the document. The 
automatic document conveyer 3 constituted according to the present 
invention is turnably mounted at the rear end on the upper surface of the 
housing 4 of the electrostatic copier 2 by means of two hinge mechanisms 7 
(see FIG. 2). The hinge mechanism 7 comprises a first support member 71 
mounted on the housing 4, a second support member 72 mounted on a moving 
frame 10 of the automatic document conveyer 3, a hinge pin 73 rotatably 
coupling the first support member 71 and the second support member 72 
together, and a compression coil spring 74 interposed between the first 
support member 71 and the second support member 72 to urge them toward the 
direction in which they are opened. The automatic document conveyer 3 is 
turnably mounted on the housing 4 by the thus constituted two hinge 
mechanisms 7, and is turned on the hinge pins 73 of the hinge mechanisms 7 
as a center between a closed position shown in FIGS. 1 and 3 and an open 
position shown in FIG. 2, the hinge pines 73 extending along the rear side 
edge of the transparent plate 5. To set a document by hand on the 
transparent plate 5 of the electrostatic copier 2, the automatic document 
conveyer 3 is brought to the open position shown in FIG. 2 to expose the 
transparent plate 5, the document is placed on a required position on the 
transparent plate 5, and the automatic document conveyer 3 is brought to 
the closed position to cover the transparent plate 5 and the document 
placed thereon. On the other hand, in the case where the document is 
automatically introduced onto the transparent plate 5 and is automatically 
discharged from the transparent plate 5 by using the automatic document 
conveyer 3, the automatic document conveyer 3 is brought to the closed 
position. 
If further described with reference to FIGS. 1 to 3, the illustrated 
automatic document conveyer 3 includes a front cover 11 and a rear cover 
12 arranged at a distance in the back-and-forth direction (direction 
perpendicular to the surface of the paper in FIG. 3). The front cover 11 
and the rear cover 12 can be formed of a suitable synthetic resin. The 
front cover 11 and the rear cover 12 are respectively mounted on a front 
support base plate 101 and on a rear support base plate 102 that 
constitute the moving frame 10. The front support base plate 101 and the 
rear support base plate 102 are formed of a steel plate. Various 
constituent elements of the automatic document conveyer 3 are directly or 
indirectly supported by the front support base plate 101 and the rear 
support base plate 102. A document-placing means 15 and a document 
discharge tray 16 are arranged between the front cover 11 and the rear 
cover 12. The document-placing means 15 includes a document table 17 that 
extends being inclined upward from a front end on the left side toward the 
rear end on the right side in FIG. 3, and an auxiliary table 18 swingably 
mounted on the rear end of the document table 17. A pair of width 
restriction members 19 are mounted on the document table 17 so as to 
freely move in the direction of width. The pair of width restriction 
members 19 are coupled together under the document table 17 via a 
rack-and-pinion mechanism (not shown) that has been known per se., and are 
allowed to move, in an interlocking manner, in a direction in which they 
approach each other and in a direction in which they separate away from 
each other. The document discharge tray 16 is disposed under the 
document-mounting means 15, and has a document-placing surface 16a formed 
in the shape of a mountain as viewed from the back-and-forth direction 
(direction perpendicular to the surface of the paper in FIG. 3). A left 
end cover 20 is disposed between a left end of the front cover 11 and a 
left end of the rear cover 12, and a right end cover 21 is disposed 
between the right ends of these covers. 
If further described with reference to FIG. 3, a forward feed means 30 is 
disposed on the downstream side of the document table 17 in the direction 
of conveyance. The forward feed means 30 has a guide plate 31 extending 
toward the downstream side of the document table 17 in the direction of 
conveyance. An opening is formed in the guide plate 31 on its downstream 
side, and a forward feed roller 32 constituting the forward feed means 30 
is disposed under the opening. The forward feed roller 32 is formed of an 
elastic material having a high coefficient of friction such as urethane 
rubber or the like, and is so disposed that the outer peripheral surface 
thereof partly protrude upward to a slight degree beyond the opening 
formed in the guide plate 31. A rotary shaft (not shown) of the forward 
feed roller 32 is drivably coupled to an electric motor 33 which is a 
drive source, via a drive power transmission mechanism that is not shown. 
A forward feed pressing mechanism 34 that constitutes the forward feed 
means 30 is disposed above the forward feed roller 32. The forward feed 
pressing mechanism 34 includes a rotary shaft 341 arranged above the 
forward feed roller 32 in parallel with the forward feed roller 32, and a 
pressing plate 342 that is secured at its upper end to the rotary shaft 
341 and acts at its lower end on the documents (P) placed on the document 
table 17 and introduced onto the guide plate 31. In the illustrated 
embodiment, the pressing plate 342 is formed of a thin stainless steel 
plate having resiliency, fastened at its upper end to the rotary shaft 341 
by a fastening means such as screw, and is so constituted as to be brought 
to an acting position where the lower end thereof acts on the upper 
surface of the uppermost one of the documents stacked on the document 
table 17 at a position above the feed roller 32 to push down the 
documents, and to a non-acting position where the lower end thereof is 
separated away from the document. 
A paper feed roller 35 is disposed on the downstream side of the forward 
feed means 30. The paper feed roller 35 is formed of a material having a 
high coefficient of friction such as urethane rubber or the like, and its 
rotary shaft is drivably coupled to the electric motor 33 which is the 
drive source, via a drive power transmission mechanism that is not shown. 
The paper feed roller 35 is so disposed that the outer peripheral surface 
thereof partly protrudes upward to a slight degree beyond the opening 
formed in the guide plate 31. 
A document separation mechanism 36 is disposed above the paper feed roller 
35. In the illustrated embodiment, the document separation mechanism 36 is 
a separation roller 37 which is constituted by a fixed shaft 371, a 
cylindrical portion 372 that is formed of a suitable synthetic resin and 
is arranged about the fixed shaft 371 so as to freely rotate, a surface 
layer portion 373 that is formed of an elastic material having a high 
coefficient of friction such as urethane rubber or the like and is fitted 
onto the outer peripheral surface of the cylindrical portion 372, and a 
torque limiter mechanism 374 arranged between the fixed shaft 371 and the 
cylindrical portion 372. The surface layer portion 373 is arranged in 
contact with the outer peripheral surface of the paper feed roller 35. The 
torque limiter mechanism 374 is constituted by a clutch mechanism which 
fixes the cylindrical portion 372 to the fixed shaft 371 when a drive 
torque larger than a predetermined value acts upon the cylindrical portion 
372. The separation roller 37 equipped with the torque limiter mechanism 
374 does not constitute a novel feature in the automatic document conveyer 
constituted according to the present invention, and may be constituted in 
a manner known per se. Therefore, its details are not described in this 
specification. 
A conveyer belt mechanism 40 is arranged under the document-placing means 
15. The conveyer belt mechanism 40 includes a support frame 41, a drive 
roller 42 and a driven roller 43 arranged in the support frame 41 in 
parallel with each other at a distance in the direction of conveyance, an 
endless conveyer belt 44 wrapped round the drive roller 42, driven roller 
43 and support frame 41, and a plurality of pushing rollers 45 disposed 
between the drive roller 42 and the driven roller 43. The lower running 
side of the conveyer belt 44 extends along the transparent plate 5 of the 
electrostatic copier 2 thereby to define a document conveying passage 46 
between them. The mechanism for supporting the conveyer belt mechanism 40 
will be described later in detail. 
A document introduction passage 80 is formed between the document conveying 
passage 46 and the paper feed roller 35. The document introduction passage 
80 is defined by an inner guide plate 801 and an outer guide plate 802. A 
pair of resist rollers 82 are arranged in the document introduction 
passage 80. The pair of resist rollers 82 include a drive roller 821 and a 
driven roller 822. The drive roller 821 of the pair of resist rollers 82 
is drivably coupled to an electric motor that is not shown, via a suitable 
drive power transmission mechanism. 
In FIG. 3, a document discharge means 90 is arranged on the right side of 
the document conveying passage 46. The document discharge means 90 
includes a document discharge passage 92, a pair of conveyer rollers 92 
arranged in the document discharge passage 92, and a pair of discharge 
rollers 96 disposed at an end of the document discharge passage 92 on the 
discharge side. The pair of conveyer rollers 94 include a drive roller 941 
and a driven roller 942, and the pair of discharge rollers 96 include a 
drive roller 961 and a driven roller 962. The drive roller 941 of the pair 
of conveyer rollers 94 and the drive roller 961 of the pair of discharge 
rollers 96 are drivably coupled to an electric motor that is not shown, 
via a suitable drive power transmission mechanism. 
Next, described below is the operation of the illustrated automatic 
document conveyer 3. 
To carry out the copying operation, the operator, first, places documents P 
to be copied on the document table 17, and inserts them forward so that 
the leading end thereof is positioned on the upper side of the forward 
feed roller 32. When the operator then depresses a copy start key, a 
solenoid (not shown) of the forward feed pressing mechanism 34 is 
energized to bring the pressing plate 342 to the acting position and push 
the documents P placed on the guide plate 31. Concurrently with pushing of 
the pressing plate 342 onto the documents P, the electric motor 33 is 
driven, so that the forward feed roller 32 and the paper feed roller 35 
are rotated in the directions indicated by arrows in FIG. 3. As the 
forward feed roller 32 is rotated in the direction indicated by an arrow 
in FIG. 3, the document is delivered due to the frictional conveying force 
produced at a contact portion between the outer peripheral surface of the 
forward feed roller 32 and the lower surface of the document at the lowest 
position in the stack of documents placed on the guide plate 31. 
When the plural pieces of documents are delivered by the forward feed 
roller 32 as described above, the document of the lowest position only is 
separated as it passes through between the paper feed roller 35 and the 
separation roller 37 of the document separation mechanism 36, and is 
conveyed into the document introduction passage 80. Then, the leading end 
of the document conveyed into the document introduction passage 80 is 
brought into contact with the nipping portion of the pair of resist 
rollers 82 that is in a non-acting state, whereby the primary paper 
feeding is ended. 
After the end of the primary paper feeding as described above, the pair of 
resist rollers 82 and the conveyer belt mechanism 40 are actuated, and the 
trailing edge of the document that is primarily fed is brought to a 
reference position for setting the document on the transparent plate 5. 
Then, the exposure operation is carried out. 
After the end of the exposure operation, the conveyer belt mechanism 40, 
the pair of conveyer rollers 94 and the pair of discharge rollers 96 of 
the document discharge means 90 are actuated, so that the document for 
which the exposure has been effected on the transparent plate 8 is 
discharged onto the document-placing surface 16a of the document discharge 
tray 16 passing through the document discharge passage 92. 
Next, described below with reference to FIGS. 4 to 10 are the support frame 
41 for supporting the conveyer belt mechanism 40 and the support means for 
mounting the support frame 41 on the front support base plate 101 and on 
the rear support base plate 102. The support frame 41 includes a front 
plate 411 and a rear plate 412 arranged in parallel at a predetermine 
distance, and coupling plates 413 and 413 for coupling the front plate 411 
and the rear plate 412 together. The rotary shaft 421 of the drive roller 
42 is rotatably supported by an end of the front plate 411 (left end in 
FIG. 4) and by an end of the rear plate 412, which constitute the support 
frame 41. A pulley 47 is fitted to an end of the rotary shaft 421 on the 
side of the rear plate 412, the pulley 47 being drivably coupled to a 
drive source via a drive power transmission mechanism that is not shown. 
Furthermore, the rotary shaft 431 of the driven roller 43 is rotatably 
supported by the other end of the front plate 411 (right end in FIG. 4) 
and by the other end of the rear plate 412, which constitute the support 
frame 41. The thus constituted support frame 41 has the rear plate 412 
supported by the rear support base plate 102 via the first support means 
50, 50, and has the front plate 411 supported by the front support base 
plate 101 via the second support means 60, 60. 
The first support means 50 will now be described with reference to FIGS. 4 
to 6. 
The first support means 50 includes a first support member 51 to be mounted 
on the rear plate 412 of the support frame 41, and a second support member 
52 to be mounted on the rear support base plate 102. The first support 
member 51 includes side walls 511 and 512 extending in parallel at a 
predetermined distance, a coupling wall 513 for coupling the ends of the 
side walls 511 and 512 together, support walls 514 and 515 extending 
outward from the other ends of the side walls 511 and 512, and a stopper 
516 that is bent outward from the upper end of the coupling wall 513, 
which are formed by bending a steel plate member. Pin-insertion holes 517 
are formed in the thus formed side walls 511 and 512 of the first support 
member 51, and support pins 53 are inserted in the pin-insertion holes 
517. Mounting holes (not shown) are formed in the support walls 514 and 
515, and the support walls 514 and 515 are secured to the rear plate 412 
of the support frame 41 by screws 54, 54 inserted in the mounting holes. 
The second support member 52 includes side walls 521 and 522 extending in 
parallel at a predetermined distance, an upper wall 523 coupling the upper 
ends of the side walls 521 and 522, and a support wall 524 formed by 
bending an end of the side wall 521 downward. The distance between the 
inner surfaces of the side walls 521 and 522 corresponds to the length 
between the outer surfaces of the side walls 511 and 512 of the first 
support member 51. Guide holes 527 and 527 are formed in the side walls 
521 and 522, the guide holes 527 and 527 being elongated in the 
up-and-down direction. The guide holes 527 and 527 are formed being 
inclined forward (toward the left in FIGS. 5 and 6) from the lower side 
toward the upper side. That is, the guide holes 527 and 527 are inclined 
toward the side opposite to the hinge mechanism 7 from the lower side to 
the upper side. The thus constituted second support member 52 is turnably 
coupled to the first support member 51 by fitting the side walls 521 and 
522 to the outer sides of the side walls 511 and 512 of the first support 
member 51 from the upper side, and then inserting the support pins 53 in 
the guide holes 527 and 527. A pushing means 55 is disposed between the 
support pin 53 and the upper wall 523 of the second support member 52. The 
pushing means 55 comprises a pushing member 551 fitted to the support pin 
53 from the upper side, and a coil spring 552 disposed between the pushing 
member 55 and the upper wall 523 of the second support member 52. 
Therefore, the urging force of the coil spring 552 acts on the support pin 
53 via the pushing member 551, and the support pin 53 is pushed toward the 
lower ends of the guide holes 527 and 527. The thus constituted second 
support member 52 is secured at its support wall 524 to the rear support 
base plate 102 by screws 57. 
Next, the second support means 60 for supporting the front plate 411 of the 
support frame 41 on the front support base plate 101 will be described 
with reference to FIGS. 4 and 7. 
The second support means 60 includes a mounting plate 61, a mounting bolt 
62 and a nut 63. The mounting plate 61 is formed of a steel plate of an 
L-shape, and has a mounting portion 611 which is a vertical portion and a 
support portion 612 which is a horizontal portion. A mounting hole 611a is 
formed in the mounting portion 611. The mounting portion 611 is mounted on 
the front surface of the front plate 411 that constitutes the support 
frame 41, by a screw 65 that is inserted in the mounting hole 611a. The 
support portion 612 has a hole 612a that is elongated in the, 
back-and-forth direction (in the up-and-down direction in FIG. 4, or in 
the right-and-left direction in FIG. 7). The thus constituted mounting 
plates 61 are attached in a number of two to the front surface of the 
front plate 411 that constitutes the support frame 41. The mounting bolt 
62 is a stepped bolt having a head portion 621, a shaft portion 622 and a 
threaded portion 623. The mounting bolt 62 is inserted in the elongated 
hole 612a formed in the support portion 612 of the mounting plate 61 from 
the lower side, the threaded portion 623 is inserted in the hole 101a 
formed in the front support base plate 101 with a washer 66 sandwiched 
therebetween, and a nut 63 is fitted thereto to support the mounting plate 
61. Therefore, the support frame 41 or the conveyer belt mechanism 40 is 
allowed to move back and forth (in the up-and-down direction in FIG. 4 or 
in the right-and-left direction in FIG. 7) with respect to the front 
support base plate 101 along the elongated hole 612a, and is further 
allowed to move up and down (in the direction perpendicular to the surface 
of the paper in FIG. 4 or in the up-and-down direction in FIG. 7) along 
the shaft portion 622 of the mounting bolt 62. A coil spring 64 is 
disposed between the washer 66 fitted to the lower surface of the front 
support base plate 101 and the support portion 612 of the mounting plate 
61, and pushes the support portion 612 toward a direction to separate away 
from the front support base plate 101 (downward in FIG. 7). 
Next, described below with reference to FIGS. 5, 6 and 8 is the motion of 
the conveyer belt mechanism 40 at the time of bringing the automatic 
document conveyer 3 from the open position to the closed position. 
FIG. 8 illustrates a state where the automatic document conveyer 3 is moved 
from the open position toward the closed position and an end of the 
conveyer belt 44 of the conveyer belt mechanism 40 on the side of the 
hinge mechanism 7 (right end in FIG. 8) is brought into contact with the 
transparent plate 5. When the automatic document conveyer 3 in the state 
of FIG. 8 is turned on the hinge pin 73 in the counterclockwise direction, 
the end of the conveyer belt mechanism 40 on the side of the hinge 
mechanism 7 (right end in FIG. 8) is pushed up with respect to the rear 
support base plate 102. The support pins 53 of the first support member 51 
mounted on the rear plate 412 of the support frame 41 of the conveyer belt 
mechanism 40 move upward along the guide holes 527 and 527 formed in the 
side walls 521 and 522 of the second support member 52 secured to the rear 
support base plate 102 against the resilient force of the coil springs 
552. Since the guide holes 527 and 527 are inclined forward from the lower 
side to the upper side, i.e., inclined toward the side opposite to the 
hinge mechanism 7, the conveyer belt mechanism 40 is moved forward, i.e., 
toward the side opposite to the hinge mechanism 7 (toward the left in FIG. 
8). At this time, the conveyer belt mechanism 40 is supported by the 
second support means 60 so as to be allowed to move in the back and forth 
direction (in the up-and-down direction in FIG. 4 or in the right-and-left 
direction in FIG. 7) with respect to the front support base plate 12 along 
the elongated hole 612a and is, therefore, allowed to move toward the 
front side of the conveyer belt mechanism 40, i.e., toward the side 
opposite to the hinge mechanism 7 (toward the left in FIG. 8). Therefore, 
though the hinge pin 73 which is a hinge fulcrum of the hinge mechanism 7 
that turnably supports the automatic document conveyer 3 locates at a 
position higher than the upper surface of the transparent plate 5, the 
position at which the conveyer belt mechanism 40 comes into contact with 
the transparent plate 5 does not undergo the displacement as the end of 
the conveyer belt 44 of the conveyer belt mechanism 40 on the side of the 
hinge mechanism 7 moves from the state of FIG. 8 where it is in contact 
with the transparent plate 5 toward the closing position. When the 
automatic document conveyer 3 is turned toward the open position and the 
conveyer belt 44 of the conveyer belt mechanism 40 separates away from the 
transparent plate 5, the support pins 53 are moved to the lower ends of 
the guide holes 527 and 527 due to the resilient force of the coil springs 
552. 
When the end of the conveyer belt mechanism 40 on the side of the hinge 
mechanism 7 moves to the closing position from the state of FIG. 8 where 
it is in contact with the transparent plate 5, the predetermined amount 
for moving the conveyer belt mechanism 40 forward, i.e., toward the side 
opposite to the hinge mechanism 7 (leftward in FIG. 8) is found from the 
following formula, i.e., the shifting amount (S) required for the guide 
holes 527 and 527 in the back-and-forth direction (in the right-and-left 
direction in FIG. 5) is found from the following formula, 
EQU S=2.multidot.R1.multidot.sin .theta./2.multidot.cos 
{[90.degree.-.theta./2]-[90.degree.-cos.sup.-1 (A/R1)]} 
where A is a distance from the upper surface of the transparent plate 5 to 
the hinge pin 73; .theta. is an angle (contact angle) of when the end of 
the conveyer belt 44 of the conveyer belt mechanism 40 on the side of the 
hinge mechanism 7 comes in contact with the transparent plate 5; and R1 is 
a distance from the hinge pin 73 to the lower end of the conveyer belt 44 
of the conveyer belt mechanism 40 on the side of the hinge mechanism 7. 
By setting the shifting amount (S) as described above, the displacement of 
the position at which the conveyer belt 44 comes in contact with the 
transparent plate 5 can be decreased to be substantially zero at the time 
when the automatic document conveyer 3 is brought to the closed position. 
Therefore, the document is prevented from being deviated even when the 
document is set by hand on the transparent plate 5. 
Next, another embodiment of the second support means 60 for supporting the 
support frame 41 of the conveyer belt mechanism 40 on the front support 
base plate 12 will be described with reference to FIGS. 9 and 10. The same 
members as those of the above-mentioned embodiment are denoted by the same 
reference numerals but their description is not repeated. 
In the second support means 60 shown in FIGS. 9 and 10, the mounting hole 
611b formed in the mounting portion 611 of the mounting plate 61 is 
elongated in the up-and-down direction. A mounting bolt 67 which is a 
stepped bolt is inserted in the mounting hole 611b which is an elongated 
hole from the front side (left side in FIG. 9), and is inserted through 
the hole 411a formed in the front plate 411 constituting the support frame 
41 of the conveyer belt mechanism 40. A nut is fitted to the bolt via a 
washer 69 that is sandwiched therebetween, to support the mounting plate 
61 in such a manner to allow to move in the up-and-down direction. That 
is, the mounting bolt 67 has a head portion 671, a shaft portion 672 and a 
threaded portion 673, and the length of the shaft portion 672 is slightly 
longer than the thickness of the mounting portion 611 of the mounting 
plate 61. Despite the nut 68 is tightened, therefore, the mounting portion 
611 is not secured to the front plate 411, i.e., the mounting plate 61 and 
the support frame 41 are allowed to move relative to each other along the 
mounting hole 611b. Like in the above-mentioned embodiment, the support 
portion 612 of the mounting plate 61 is supported by the front support 
base plate 101 so as to allow to move in the up-and-down direction (in the 
up-and-down direction in FIG. 9) along the shaft portion 622 of the 
mounting bolt 62. Therefore, the support frame 41 supported by the 
mounting plate 61, i.e., the front side of the conveyer belt mechanism 40 
is supported by the front support base plate 101 with an amount of 
suspension (H) equal to the sum of the length in the up-and-down direction 
of the mounting hole 611b and the length of the shaft portion 622 of the 
mounting bolt 62. By setting the amount of suspension (H) to a 
predetermined value, the conveyer belt 44 of the conveyer belt mechanism 
40 can be brought into contact with the transparent plate 5 in parallel 
therewith. The amount of suspension (H) required for bringing the conveyer 
belt into contact with the transparent plate 5 in parallel therewith is 
found from the following equation, 
EQU H=B.multidot.tan .theta. 
where .theta. is an angle (contact angle) of when the conveyer belt 44 of 
the conveyer belt mechanism 40 comes in contact with the transparent plate 
5, and B is the width of the conveyer belt 44 of the conveyer belt 
mechanism 40. 
By setting the amount of suspension (H) as described above, it is allowed 
to bring the conveyer belt 44 of the conveyer belt mechanism 40 into 
contact with the transparent plate 5 in parallel therewith at the time 
when the automatic document conveyer 3 is to be brought to the closed 
position. Even when the document is set by hand on the transparent plate 
5, the document is more reliably prevented from being deviated. In the 
illustrated embodiment, the amount of suspension (H) is shared by the 
mounting hole 611b having an elongated shape formed in the mounting 
portion 611 of the mounting plate 61 and by the shaft portion of the 
mounting bolt 62 inserted through the support portion 612, and, hence, 
protrusion of the mounting portion 611 or the mounting bolt 62 of the 
mounting plate 61 can be decreased to a small degree. 
When the conveyer belt 44 of the conveyer belt mechanism 40 moves to the 
closed position from the state of FIG. 10 where it is in contact with the 
transparent plate 5, the required shifting amount (S) in the 
back-and-forth direction (in the right-and-left direction in FIG. 5) is 
found from the following formula, 
EQU S=2.multidot.R2.multidot.sin .theta./2.multidot.cos 
{[90.degree.-.theta./2]-[90.degree.-cos.sup.-1 ((A-T)/R2)]} 
where A is a distance from the upper surface of the transparent plate 5 to 
the hinge pin 73; .theta. is an angle (contact angle) of when the conveyer 
belt 44 of the conveyer belt mechanism 40 comes in contact with the 
transparent plate 5; R2 is a distance from the hinge pin 73 to the upper 
end of the conveyer belt 44 of the conveyer belt mechanism 40 on the side 
of the hinge mechanism 7; and T is a distance from the upper surface of 
the conveyer belt 44 of the upper side to the lower surface of the 
conveyer belt 44 of the lower side. 
Being constituted as described above, the automatic document conveyer of 
the present invention exhibits actions and effects as described below. 
That is, when the moving frame is turned toward the closing position, the 
conveyer belt mechanism is moved by a predetermined amount toward the side 
opposite to the hinge mechanism while the end of the conveyer belt on the 
side of the hinge mechanism reaches to the closing position after having 
come in contact with the transparent plate. Therefore, despite the hinge 
fulcrum of the hinge mechanism which turnably supports the automatic 
document conveyer locates at a position higher than the upper surface of 
the transparent plate, the position at which the conveyer belt mechanism 
comes into contact with the transparent plate does not undergo the 
displacement irrespective of the motion of the end of the conveyer belt on 
the side of the hinge mechanism from the state where it is in contact with 
the transparent plate toward the closing position. When the document is 
set by hand on the transparent plate, therefore, the document is prevented 
from being deviated. Even in the copiers of the type in which the document 
is set to a document instruction plate on the side of the hinge mechanism 
(rear side), therefore, the document is prevented from being deflected or 
from floating. Besides, the hinge fulcrum of the hinge mechanism can be 
freely set.