Supporting mechanism of a document cover lid for a copying apparatus

A supporting mechanism of a document cover lid to be used for a copying apparatus includes a base of a supporting member mounted to the upper portion of an apparatus housing so as to swing about a horizontal axis. A positioning member is mounted on one of either the apparatus housing or the supporting member has a first frictional surface which is a circular periphery in a vertical plane with respect to the horizontal axis. A contact member is mounted on the other of either the apparatus housing or the supporting member and, has a second frictional surface, which is a circular periphery in a vertical plane with respect to the horizontal axis and is elastically pushed against the first frictional surface. By this mechanism, it is possible to support the document cover lid in an opened position upwardly at an angle sufficient to replace an original document.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a supporting mechanism for a document 
cover lid to be used for a copying apparatus, and more particularly to a 
supporting means capable of remaining the document cover lid in its fully 
raised position sufficient to allow the replacement of an original 
document on a transparent glass plate of the copying apparatus. 
2. Description of the Prior Art 
In a conventional typical copying apparatus, the replacement of an original 
document on a transparent glass plate is carried out by one hand while a 
document cover lid is raised above the plate surface by the other hand. 
Therefore raising or lowering of the document cover lid is very 
complicated. The larger is the copying apparatus, the heavier is the 
document cover lid. It is difficult to maintain the document cover lid in 
its fully raised position by one hand for replacement of the original 
document. 
Accordingly, it is an object of the invention to provide an improved 
supporting mechanism for a document cover lid to be used for a copying 
apparatus. 
It is an object of the invention to provide a supporting mechanism for a 
document cover lid to be used for a copying apparatus capable of 
supporting the document cover lid in an opened position extending upwardly 
at an angle sufficient to replace the original document. 
SUMMARY OF THE INVENTION 
To accomplish the foregoing objectives, there is provided an improved 
supporting mechanism for a document cover lid for a copying apparatus 
wherein a base of a supporting member is mounted to the upper portion of 
an apparatus housing so as to swing about a horizontal axis. A positioning 
member is mounted on one of either the apparatus housing or the supporting 
member and has a first frictional surface which is a circular periphery in 
a vertical plane with respect to the horizontal axis. A contact member is 
mounted on the other of either the apparatus housing or the supporting 
member and has a second frictional surface, which is a circular periphery 
in a vertical plane with respect to the horizontal axis and is elastically 
pushed against the first frictional surface. Therefore, it is possible to 
support the document cover lid in an opened position extending upwardly at 
an angle sufficient to enable replacement of the original document. 
According to another aspect of the invention, the positioning member is 
mounted on the apparatus housing, and the contact portion between the 
first frictional surface and the second frictional surface is positioned 
lower than a horizontal line including the center of the first frictional 
surface of the positioning member when the document cover lid is in a 
closed position. According to further aspect of the invention, the contact 
member is mounted on the apparatus housing, and the contact portion 
between the first frictional surface and the second frictional surface is 
positioned lower than the horizontal line including the center of the 
second frictional surface of the contact member when the document cover 
lid is in a closed position. Therefore, the document cover lid depresses 
an original document onto a transparent plate when the document cover lid 
is closed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
The following detailed description is of the best presently contemplated 
mode of carrying out the invention. This description is not to be taken in 
a limiting sense, but is made merely for the purpose of illustrating the 
general principles of the invention since the scope of the invention is 
best defined by the appended claims. 
FIG. 1 is an overall perspective view of an embodiment of the invention. 
This electrostatic copying apparatus comprises an optical means (not 
shown) which is scanned horizontally in the lateral direction (right and 
left as viewed in FIG. 1) of an apparatus housing 1 for projecting an 
image of an original document 2 shown by phantom lines through a slit onto 
a moving photoconductive surface. A transparent glass plate 3 is mounted 
on the top surface of the apparatus housing 1 to allow the original 
document 2 to be placed thereon. A part of the aforementioned movable 
optical means is mounted beneath the transparent glass plate 3. The 
original document 2 on the transparent glass plate 3 is covered with a 
document cover lid 4 supported by supporting rods 5 and 6. The bases of 
the supporting rods 5 and 6 are pivotally mounted by means of hinge 
members 7 and 8 fixed to the rear end of the apparatus housing 1. 
Accordingly this side of the document cover lid 4, as viewed by the 
operator, is pivotally raised above the transparent glass plate 3 as shown 
in FIG. 1. A feeding cassette 9 stored with copy papers is detachably 
mounted to one side wall of the apparatus housing 1, and a copy collection 
tray 10 is also mounted to the other side wall so as to receive copy 
papers to be reproduced. An operating mechanism 11 is located on the upper 
front portion of the apparatus housing 1. 
FIG. 2 is an enlarged perspective view in the vicinity of the document 
cover lid 4, and FIG. 3 is an enlarged perspective view in the vicinity of 
the base of the supporting rod 5, with parts broken away, showing further 
detailed of its construction. The document cover lid 4 comprises a frame 
12 of rigid material and a retaining pad 13 manufactured of elastic 
material, such as polyurethane, which is adhered to the underside of the 
rigid frame 12 facing the transparent glass plate 3. The rigid frame 12 
comprises a rectangular flat portion 12a, and three vertical walls 12b, 
12c and 12d which do not cover the opening areas of the vicinity of the 
hinge members 7 and 8. The depth "d" of the retaining pad 13 is thicker 
than the height "h" of each wall 12b, 12c and 12d. Therefore, when the 
document cover lid 4 is pivoted downward to cover the original document 2 
on the transparent glass plate 3, the retaining pad 13 substantially holds 
the original document 2 thereon. 
Each of the hinge members 7 and 8 is formed in a U-shaped fashion having an 
area opening upwardly. Hinge members 7 and 8 have horizontal supporting 
shafts 14 pivotally mounted through respective supporting portions 7a and 
7b, 8a and 8b. The supporting rods 5 and 6 extend along the insides of the 
walls 12c and 12d, and are fixedly mounted to the rigid frame 12. The 
bases of the supporting rods 5 and 6 are vertically fixed to the 
supporting shafts 14. 
FIG. 4 is a cross sectional view in the vicinity of the base of the 
supporting rod 5 when the document cover lid 4 is in a closed position. A 
cylindrical positioning member 15, having an axis in parallel to that of 
the supporting shaft 14, is fixed to the hinge member 7. The peripheral 
surface of the positioning member 15 is first frictional surface 16. 
A guide member 17 is fixedly mounted to the base of the supporting rod 5. 
The guide member 17 has a guide hole 18 formed in parallel alignment with 
the axis of the supporting rod 5. A contact member 19 to be in contact 
with the positioning member 15 is inserted in one side of the guide hole 
18 facing the supporting shaft 14, and an end plate 20 occupies the other 
side. An supporting plate 21, provided with an adjustment screw 22 for 
fastening or loosening, is attached adjacent to the end plate 20 in the 
guide hole 18. A movable receiving plate 23 is adjustably disposed between 
the supporting plate 21 and the contact member 19 so as to be in contact 
with the adjustment screw 22 and in alignment with the guide hole 18. The 
end plate 20 has a hole 24 so that the adjustment screw 22 may be fastened 
or loosened through hole 24 by means of a driver. A spring 25 is provided 
between the receiving plate 23 and the contact member 19. Accordingly the 
contact member 19 is elastically pushed toward the supporting shaft 14 by 
the spring 25. 
The contact member 19 has a second frictional surface 26 which is a 
half-circle end in a vertical plane with respect to an axis 16a of the 
positioning member 15 and is convex toward the supporting shaft 14. The 
positioning member 15 is placed so that the second frictional surface 26 
of the contact member 19 always is in contact with the first frictional 
surface 16 of the positioning member 15 and can be elastically pushed 
toward the supporting shaft 14. When the document cover lid 4 is in a 
closed position as shown in FIG. 4, the mounting position of the 
positioning member 15 is determined so that the axis 26a of the second 
frictional surface 26 is lower than the axis 16a of the first frictional 
surface 16. Therefore, when the document cover lid 4 is closed, the first 
frictional surface 16 comes in contact with the second frictional surface 
26 at a position which is lower than the axis of the positioning member 15 
(refer to the axis 16a in this embodiment). Therefore the guide member 17 
and the supporting rod 5 are provided with a downward force exerted by the 
spring 25 about the supporting shaft 14 as shown by an arrow 27. When the 
document cover lid 4 contacts the plate surface, the original document 2 
can be substantially held on the transparent glass plate 3. 
The base of another supporting rod 6 has the same construction as that of 
the supporting rod 5. 
Referring to FIG. 5, when the document cover lid 4 is in its fully raised 
position, the contact member 19 comes in contact with the supporting shaft 
14 and the positioning member 15. In this condition, since the contact 
member 19 is pushed by the force of the spring 25, the frictional force 
exerted between the first frictional surface 16 and the second frictional 
surface 26 is larger than the force due to the weight of the document 
cover lid 4 tending to close the cover lid 4. Therefore, even when the 
operator takes his hand off the document cover lid 4, will remain in the 
raised position as shown in FIG. 5. A hollow 28 (as shown by a phantom 
line) may be formed in member 19 at the contact area between the 
positioning member 15 and the contact member 19, and the positioning 
member 15 may engage with the hollow 28 so as to cause the document cover 
lid 4 substantially to be held in its raised position. 
Referring to FIG. 6, when the document cover lid 4 is slightly moved from 
its fully raised position as shown in FIG. 5, the contact member 19 still 
is maintained in contact with the positioning member 15. In this position, 
the force exerted by the spring 25 is determined so that the frictional 
force between the first frictional surface 16 and the second frictional 
surface 26 is larger than the force due to the weight of the document 
cover lid 4 tending to close the cover lid. Adjusting the adjustable screw 
22 through the hole 24 with a driver allows the document cover lid 4 to be 
substantially raised in a desired position sufficient to allow the 
replacement of an original document on the transparent glass plate 3. 
According to another aspect of the invention, the supporting rods 5 and 6 
may be provided with the positioning member 15, and the hinge members 7 
and 8 may be provided with the guide member 17, the spring 25 and the 
contact member 19.