Paper feeder

A paper feeder capable of reducing its installation space and manufacturing cost, wherein a paper feed table which can be lifted or lowered being held horizontal is provided with an opening section. In order to load paper sheets onto the paper feed table directly from above, the opening section is made openable upwards when the paper feeder is in a paper feeding state during which paper sheets are picked up and fed to a photosensitive drum or similar device. The paper feeder also has a pick-up member for picking up the paper sheets thus loaded onto the paper feed table one after another starting with the top sheet in order to feed them to the photosensitive drum or similar device.

BACKGROUND OF THE INVENTION 
(1) Field of the Invention 
The present invention relates to a paper feeder for use with various types 
of electrophotographic devices including facsimiles, printers and copying 
machines, in which paper sheets stacked on a paper feed table are picked 
up one after another for feeding, starting with a top sheet. 
(2) Description of the Prior Art 
In recent years, in order to meet the demand for higher feeding capacity 
which has been growing with the increase in the speed of the printing 
process, a paper feeder in which paper sheets are replenished in the 
following manner is widely used for feeding paper sheets to such an 
electrophotographic device as mentioned above. 
For replenishment of paper sheets, the paper feed table, which is housed in 
the paper feeder and can be lifted or lowered with paper sheets stacked 
thereon, is firstly lowered to the lowest position and pulled forwards 
with the help of sliding rails or similar devices. Then, paper sheets are 
loaded onto the paper feed table thus pulled out. After the loading, the 
paper feed table is pushed back with the help of the sliding rails and 
housed in the paper feeder. 
SUMMARY OF THE INVENTION 
Such a paper feeder of the so-called pulling-out type requires a space for 
accommodating the paper feed table which has been pulled forward and this 
could be a problem in saving installation space. It also has a problem in 
saving any manufacturing costs. Because, such a paper feeder requires not 
only sliding rails or similar devices in order to pull the paper feed 
table out of the paper feeder and push it back thereto, but also a link 
mechanism which is used for connecting the paper feed table with the 
driving mechanism for lifting or lowering it and disconnecting the former 
from the latter, such connection/disconnection taking place when the paper 
feed table is pulled out of the paper feeder, or when it is pushed back 
thereto. 
One of the objects of the invention is therefore to provide a paper feeder 
with which not only the installation space but also the manufacturing cost 
can be saved by overcoming the above disadvantages. 
In order to accomplish the foregoing object, a paper feeder according to 
the invention comprises: 
(a) an opening section having an upper part which is openable when the 
paper feeder is in a paper feeding state during which paper sheets are 
picked up and fed; 
(b) a paper feed table which can be lifted to the opening section or 
lowered therefrom being held horizontal and onto which the paper sheets 
are loaded from above through the opening section; and 
(c) a pick-up member for picking up the paper sheets stacked on the paper 
feed table one after another for feeding, starting with a top sheet. 
As described above, the replenishment of paper sheets is carried out as 
follows: paper sheets are loaded from above onto the paper feed table that 
can be lifted towards the opening section or lowered therefrom being held 
horizontal, through the opening section upper part of which is openable 
when the paper feeder is in its paper feeding state during which the paper 
sheets are picked up and fed. The paper sheets thus loaded onto the paper 
feed table are picked up one after another by the pick-up member starting 
with the top sheet, in order to feed to a photosensitive drum or other 
device. 
With the above arrangement, the paper sheets to be replenished can be 
directly loaded from above onto the paper feed table through the opening 
section upper part of which is openable when the paper feeder is in its 
paper feeding state. This eliminates the need for a space previously 
required for accommodating the paper feed table which has been pulled 
forwards and sliding rails or similar devices, so that installation space 
and manufacturing costs can be advantageously saved. 
In cases where at least a part of the pick-up member projects above the 
paper sheets stacked on the paper feed table, the part of the pick-up 
member is preferably retractable from the position above the paper feed 
table. Similarly, in cases where at least a part of a paper 
presence/absence detector for detecting the presence/absence of paper 
sheets on the paper feed table projects above the paper sheets stacked on 
the paper feed table, the part of the paper presence/absence detector is 
preferably retractable from the position above the paper feed table 
concomitantly with the retraction of the part of the pick-up member from 
the paper feed table. Those retractions facilitate the loading of paper 
sheets onto the paper feed table from above. 
In cases where the opening section is provided with a cover, the part of 
the pick-up member and the part of the paper presence/absence detector are 
preferably retractable from their respective positions above the paper 
feed table concomitantly with the opening of the cover. The above part of 
the pick-up member may be a pick-up roller, and the above part of the 
paper presence/absence detector may be a paper absence detection lever. 
When there is no paper sheet on the paper feed table, the paper absence 
detection lever downwardly pivots about the axis of a shaft disposed on a 
side of the paper feed table so that its tip portion is fitted into a hole 
defined at the paper feed table. 
Concretely, the retraction of the pick-up roller and the retraction of the 
paper absence detection lever, which are concomitant with the opening of 
the cover, are done in the following manner: 
1. the shaft disposed on a side of the paper feed table, for supporting the 
pick-up roller so as to inhibit the forward and backward rotations of the 
pick-up roller is rotated, whereby the pick-up roller is allowed to pivot 
upwardly about the axis of the shaft concomitantly with the opening of the 
cover with the help of a link mechanism; 
2. the shaft disposed on a side of the paper feed table, for supporting the 
paper absence detection lever so as to allow its forward and backward 
rotations and the pick-up roller so as to inhibit its forward and backward 
rotations is rotated, whereby the pick-up roller pivots upwardly about the 
axis of the shaft concomitantly with the opening of the cover with the 
help of the link mechanism, whilst the paper absence detection lever 
pivots upwardly, being engaged with the upwardly pivoting pick-up roller. 
In cases where paper sheets are loaded from above onto the paper feed table 
through the opening section which is openable when the paper feeder is in 
its paper feeding state during which paper sheets are picked up and fed, 
the paper feeder preferably comprises: 
(a) holding means for holding the paper feed table such that the paper feed 
table can be lifted or lowered being held horizontal; 
(b) feeding level maintaining means for lifting the paper feed table held 
horizontal by the holding means, for paper feeding, such that a top sheet 
of paper sheets stacked on the paper feed table is kept at a predetermined 
feeding level; and 
(c) loading level maintaining means for lowering the paper feed table held 
horizontal by the holding means, for loading, such that when paper sheets 
are not stacked on the paper feed table, the paper feed table is kept at a 
predetermined loading level that is lower than the feeding level; and such 
that when paper sheets are stacked on the paper feed table, the top sheet 
of the paper sheets is kept at the loading level, whereby paper sheets to 
be replenished can be loaded onto the paper feed table at the loading 
level. Accordingly, when loading paper sheets from above onto the paper 
feed table through the opening section, the loading can be performed at a 
predetermined loading level that is lower than a predetermined feeding 
level. More specifically, when there is no paper sheet on the paper feed 
table, paper sheets are loaded onto the paper feed table maintained at the 
predetermined loading level by the loading level maintaining means. On the 
other hand, when there are paper sheets stacked on the paper feed table, 
another supply of paper sheets are stacked on the top sheet of the stacked 
paper sheets, the top sheet being maintained at the loading level by the 
loading level maintaining means. Thus, the stacking of paper sheets on the 
paper feed table can be carried out in a stable condition, thereby 
facilitating the replenishment operation. 
One preferred embodiment of the holding means includes an endless rope at 
least on each of opposite sides of the paper feed table. Each of the 
endless ropes is extended in a figure-eight fashion so as to form vertical 
portions on a plane parallel with an ascending/descending plane of the 
paper feed table. The paper feed table is horizontally suspended being 
secured to the vertical portions of the extended endless ropes, whereby 
the paper feed table is so supported as to be lifted or lowered being kept 
in a horizontal condition. The endless ropes are wound around a plurality 
of pairs of pulleys in a figure-eight fashion on the respective sides of 
the paper feed table. The pulleys constituting a pair are arranged in a 
vertical direction and a plurality of such pulleys are aligned along both 
sides of the paper feed table. 
In one preferred embodiment of the feeding level maintaining means, an 
endless rubber belt serves as a belt member. Such feeding level 
maintaining means comprises: 
(a) endless rubber belt(s) extended on a side of the paper feed table in 
the ascending/descending directions thereof and (each) including an 
engaging member which is brought into engagement with the underside of the 
paper feed table; and 
(b) a driving mechanism for driving the endless rubber belt(s) in the 
ascending/descending directions of the paper feed table. During paper 
feeding, the driving mechanism actuates the endless rubber belt(s), with 
the engaging member(s) of it(them) being engaged with the underside of the 
paper feed table in order to lift the paper feed table such that the top 
sheet of paper sheets stacked thereon is maintained at the predetermined 
feeding level. 
In one preferred embodiment of the loading level maintaining means, a 
tension coil spring serves as an elastic member. Such loading level 
maintaining means comprises a tension coil spring for imparting an elastic 
tension force in the ascending direction of the paper feed table. During 
loading of paper sheets, the paper feed table is lowered against the 
elastic tension force of the tension coil spring as paper sheets are 
loaded, whereby when there is no paper sheet on the paper feed table, the 
paper feed table is kept at the predetermined loading level and whereby 
when there are paper sheets stacked on the paper feed table, the top sheet 
of the stacked paper sheets is kept at the predetermined loading level. 
Other objects of the present invention will become apparent from the 
detailed description given hereinafter. However, it should be understood 
that the detailed description and specific examples, while indicating 
preferred embodiments of the invention, are given by way of illustration 
only, since various changes and modifications within the spirit and scope 
of the invention will become apparent to those skilled in the art from 
this detailed description.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings, concrete embodiments of a paper feeder 
according to the invention will be hereinafter described. 
FIG. 1 shows a main body 2 of an electrophotographic device 1 such as a 
facsimile, printer or copying machine, and a paper feeder 3 to which the 
invention is applied. The paper feeder 3 is of the separation type which 
is constructed separately from the main body 2, and when it is used, it is 
installed together with the main body 2 as shown in FIG. 1. The main body 
2 of the electrophotographic device 1 is also provided with a paper feed 
tray 4 composed of three cassettes. A stack of paper sheets 5 is stored in 
the paper feeder 3 and another stack of paper sheets 5' in the paper feed 
tray 4. Either of the stacks 5, 5' being selected, the paper sheets 5 (5') 
are sequentially picked up starting with the top sheet and fed to a 
photosensitive drum (not shown) or other device incorporated within the 
main body 2. Thereafter, with a known electrophotographic procedure, 
desired images are transferred by means of the photosensitive drum etc. 
onto the paper sheets which have been fed, and thus printing, copying etc. 
are executed. 
In FIG. 2, the paper feeder 3 to which the invention is applied has a 
casing 6 in which an opening section 8 is formed at the upper face 
thereof. Disposed over the opening section 8 is a cover 7 which can be 
opened or closed in the direction indicated by the arrow a of FIG. 2, so 
that the opening section 8 is openable when the paper feeder 3 is in its 
paper feeding condition (shown in FIG. 1) during which the paper sheets 
are picked up and fed to the main body 2. Incorporated within the casing 6 
is a paper hopper 9 that is open at the upper part thereof. Within the 
paper hopper 9 is a paper feed table 10 loosely fitted in a horizontal 
condition. There are the paper sheets 5 of a specified size (e.g., 
A4-size) stacked on the paper feed table 10. 
The paper feed table 10 is provided with the following mechanisms: 
(1) a holding mechanism A for holding the paper feed table 10 such that it 
can be lifted or lowered being held horizontal; 
(2) a feeding level maintaining mechanism B for lifting the paper feed 
table 10, for paper feeding, such that the top sheet of the paper sheets 5 
stacked thereon is maintained at a feeding level indicated by the arrow X 
of FIG. 2; 
(3) a loading level maintaining mechanism C for lowering the paper feed 
table 10, for loading, such that when there is no paper sheet on the paper 
feed table 10, the paper feed table 10 is kept at a loading level 
indicated by the arrow Y of FIG. 2 that is lower than the feeding level X; 
and such that when there are the paper sheets 5 stacked on the paper feed 
table 10, the top sheet of the paper sheets 5 is kept at the loading level 
Y, whereby paper sheets to be replenished can be loaded onto the paper 
feed table 10 at the loading level Y. 
There is provided a pick-up mechanism D on the paper feeding side of the 
paper feeder, adjacent to the opening of the paper hopper 9. The pick-up 
mechanism D picks up the paper sheets 5 stacked on the paper feed table 10 
one after another starting with the top sheet and feeds them to the main 
body 2. There are also provided a paper presence/absence detector (not 
shown) for detecting whether or not paper sheets are stacked on the paper 
feed table 10, and a feeding level detector (not shown) which constitutes 
a part of the feeding level maintaining mechanism B and has the function 
of detecting whether or not the top sheet of the paper sheets 5 stacked on 
the paper feed table 10 is kept at the feeding level X. 
In order to describe the holding mechanism A, the feeding level maintaining 
mechanism B and the loading level maintaining mechanism C in that order, 
reference is now made to FIG. 2 and further to FIG. 3 which schematically 
shows those mechanisms. 
(1) Holding mechanism A 
The paper hopper 9 is provided with a pair of guide grooves 15 (15') which 
are aligned in a parallel direction with the paper feeding direction b at 
each of side walls 9a, 9b of the paper hopper 9, the side walls 9a, 9b 
being situated at the right and left with respect to the paper feeding 
direction b. The guide grooves 15 (15') extend in a vertical direction. 
Projections 16 (16') are provided on each side of the paper feed table 10 
loosely fitted in the paper hopper 9, so as to correspond to the guide 
grooves 15 (15'), the sides being situated at the right and left of the 
paper feeding direction b. Those projections 16 (16') project, being 
loosely inserted into the corresponding guide grooves 15 (15'). Each of 
the side walls 9a, 9b of the paper hopper 9 is provided with pulleys 17a 
through 17d (17a' through 17d') fixedly attached to the outer face 
thereof. Specifically, the pulleys in each pair are vertically aligned and 
two pairs of pulleys 17a and 17b (17a' and 17b'); 17c and 17d (17c' and 
17d') are aligned in a parallel direction with the paper feeding direction 
b. An endless wire rope 18 (18') is extended, being wound around those 
pairs of pulleys 17a through 17d (17a' through 17d') in figure-eight 
fashion so as to form vertical portions on a plane parallel with an 
ascending/descending plane of the paper feed table 10. The paper feed 
table 10 is suspended being fixed in a horizontal condition at the 
vertical portions of the endless wire rope 18 (18') by means of the 
projections 16 (16'). This allows the paper feed table 10 to be lifted to 
or lowered from the opening section 8, being kept in a horizontal 
condition. 
(2) Feeding level maintaining mechanism B 
The paper hopper 9 is provided with two pairs of pulleys 19a, 19b; 19a', 
19b' at the outer face of a rear wall 9c, the rear wall 9c while being 
situated on a side opposite to the feeding side. Specifically, the pulleys 
in each pair are aligned vertically. The pair of pulleys 19a, 19b is 
situated at the left; the pair of pulleys 19a', 19b' is at the right with 
respect to the paper feeding direction b. Of those pulleys 19a, 19b, 19a' 
and 19b', the upper pulleys 19a, 19a' are independently fixed to the rear 
wall 9c of the paper hopper 9 whilst the lower pulleys 19b, 19b' are 
coupled to a common rotary shaft 20. The rotary shaft 20 is so supported 
at the rear wall 9c of the paper hopper 9 as to pivot in forward and 
backward directions. The rotary shaft 20 is provided with a coaxial gear 
23 which meshes with a gear 22 of a driving motor 21 so that the forward 
and backward rotations of the driving motor 21 are transmitted to the 
pulleys 19b, 19b'. An endless rubber belt 24 is extended being wound 
around the pair of vertically aligned pulleys 19a, 19b, and another 
endless rubber belt 24' is extended being wound around the pair of 
vertically aligned pulleys 19a', 19b'. The endless rubber belts 24, 24' 
have engaging pieces 25, 25' respectively. Those engaging pieces 25, 25' 
project from the endless rubber belts 24, 24', being loosely inserted into 
guide grooves 26, 26' respectively so that they can be engaged with the 
underside of the paper feed table 10. The guide grooves 26, 26' are 
defined at the right and left of the paper feeding direction b in the rear 
wall 9c of the paper hopper 9 such that they correspond to the engaging 
pieces 25, 25' respectively and extend vertically. For paper feeding, the 
driving motor 21 forwardly rotates, thereby moving the endless rubber 
belts 24, 24' in a forward direction c shown in FIG. 3. This movement 
causes the engaging pieces 25, 25' attached to the endless rubber belts 
24, 24' to move upwards and then be brought into engagement with the 
underside of the paper feed table 10. The paper feed table 10 engaged with 
the engaging pieces 25, 25' is lifted until the feeding level detector 
detects that the top sheet of the paper sheets 5 stacked on the paper feed 
table 10 has reached the feeding level X and the driving motor 21 is 
stopped. As the paper sheets 5 are picked up, the driving motor 21 is 
actuated in the forward direction, based on the detection by the feeding 
level detector as to whether or not the top sheet is positioned at the 
feeding level X. Consequently, the paper feed table 10 is lifted such that 
the top sheet is maintained at the feeding level X. 
(3) Loading level maintaining mechanism C 
The paper hopper 9 is provided with pulleys 27, 27' which have the same 
axes as those of the pulleys 17, 17' of the holding mechanism A 
respectively, the pulleys 17, 17' being located at upper positions (closer 
to the paper feeding side) on the respective outer faces of the side walls 
9a, 9b of the paper hopper 9. Wound around the pulleys 27 (27') is a wire 
rope 28 (28') one end of which is so suspended as to be secured to the 
projection 16 (16') of the paper feed table 10. The other end of the wire 
rope 28 (28') is suspended so as to be connected to one end of a tension 
coil spring 29 (29'). The other end of the tension coil spring 29 (29') is 
fixed to the bottom of the casing 6. The tension coil spring 29 (29') has 
a spring constant with which a lifting force is applied to the paper feed 
table 10 such that when there is no paper sheet on the paper feed table 
10, the paper feed table 10 is maintained at the loading level Y and such 
that when there are paper sheets stacked on the paper feed table 10, the 
top sheet of the stacked paper sheets 5 is maintained at the loading level 
Y. For loading paper sheets, the driving motor 21 of the feeding level 
maintaining mechanism B is actuated in the backward direction, thereby 
moving the end-less rubber belts 24, 24' in a direction opposite to the 
forward direction c shown in FIG. 3. This causes the engaging pieces 25, 
25' attached to the endless rubber belts 24, 24' to be lowered so that the 
engaging pieces 25, 25' are released from the engagement with the paper 
feed table 10. Consequently, the paper feed table 10 is lowered until the 
paper feed table 10 reaches the loading the level Y when there is no paper 
sheet thereon or until the top sheet of the stacked paper sheets 5 reaches 
the loading level Y when there are paper sheets stacked on the paper feed 
table 10. Upon completion of the loading of the paper sheets onto the 
paper feed table 10, the paper feed table 10 is lowered again so that the 
top sheet of the loaded paper sheets comes to the loading level Y. 
With reference to FIG. 4 showing a partially enlarged perspective view, the 
pick-up mechanism D, the paper presence/absence detector, the feeding 
level detector will be described in that order. 
(a) Pick-up mechanism D 
On the paper feeding side on a side of the paper feed table 10, there are a 
first rotary shaft 35, a second rotary shaft 36, a third rotary shaft 37 
disposed in order in the paper feeding direction b viewed from the paper 
feed table 10. The second rotary shaft 36 and the third rotary shaft 37 
are driven by different driving motors (not shown). The first through 
third rotary shafts 35, 36, 37 are so supported at positions on the casing 
6 side as to rotate in the forward and backward directions. The first 
rotary shaft 35 is provided with a pair of pick-up rollers 38a, 38b which 
project above the paper sheets stacked on the paper feed table 10 and are 
brought into contact with the top sheet from above by their own weight, 
when they are in operation. The pick-up rollers 38a, 38b have a common 
rotary shaft 39 which is supported by supporting arms 40a, 40b at the 
respective ends of the arms 40a, 40b so as to rotate forwardly and 
backwardly, and the other ends of the supporting arms 40a, 40b are secured 
to the first rotary shaft 35, whereby the pick-up rollers 38a, 38b are 
supported by the first rotary shaft 35 with the help of the supporting 
arms 40a, 40b so as not to rotate forwardly and backwardly in relation to 
the first rotary shaft 35. The rotary movement is transmitted in turn from 
the second rotary shaft 36 to the pick-up rollers 38a, 38b by way of gears 
41 to 43 secured to the first and second rotary shafts 35, 36 and the 
common rotary shaft 39, and intermediate gears 44, 45 that are disposed 
between the gears 41 through 43, being in mesh therewith. An endless feed 
belt 46 is extended, being wound around the first and second rotary shafts 
35, 36 such that the endless feed belt 46 slides freely in relation to the 
first rotary shaft 35. A driven roller 47 is disposed facing to the 
underside of the endless feed belt 46. Three delivery rollers 48a through 
48c are secured to the third rotary shaft 37, and driven rollers 49a 
through 49c are disposed over the delivery rollers 48a through 48c facing 
thereto. The second and third rotary shafts 36, 37 are intermittently 
rotated in the direction of the arrow d and the direction of the arrow e 
(shown in FIG. 4) respectively by means of the aforesaid different driving 
motors in such a manner that the latter rotates slower than the former. 
With such an arrangement, the paper sheets stacked on the paper feed table 
10 are picked up from the top sheet by means of the pick-up rollers 38a, 
38b. After being picked up, the paper sheets are gripped between the 
endless feed belt 46 and the driven roller 47 and then between the 
delivery rollers 48a through 48c and the driven rollers 49a through 49c so 
as to be delivered to the main body 2 of the electrophotographic device. 
(b) Paper presence/absence detector 
The first rotary shaft 35 is also provided with a paper absence detection 
lever 51 that is so supported as to rotate forwardly and backwardly in 
relation to the first rotary shaft 35. The paper absence detection lever 
51 has an engaging piece 50 integrally formed therewith. The engaging 
piece 50 is able to come in contact with the upper end (shown in FIG. 4) 
of the supporting arm 40b from above, the supporting arm 40b being one of 
the arms which support the common rotary axis 39 of the pick-up rollers 
38a, 38b, and this contact permits the engaging piece 50 to be engaged 
with the supporting arm 40b. A paper absence sensor 52 is provided in 
connection with the paper absence detection lever 51. The paper absence 
sensor 52 is comprised of a light emitting element and a light receiving 
element for receiving light emitted from the light emitting element. A 
light interrupting segment 53 is integrally formed with the paper absence 
detection lever 51. This light interrupting segment 53 has the function of 
interrupting light sent from the light emitting element to the light 
receiving element, being positioned between them when there are paper 
sheets stacked on the paper feed table 10. The paper feed table 10 is 
provided with a hole 54 defined at a position opposite to the tip portion 
of the paper absence detection lever 51 so that the tip portion can be 
fitted into the hole 54. When there are paper sheets on the paper feed 
table 10, the paper absence detection lever 51, which projects above the 
paper sheets on the paper feed table 10 during paper feeding like the 
pick-up rollers 38a, 38b etc., is prevented from pivoting downwards by its 
own weight because the stack of paper sheets prevents its tip portion from 
being fitted into the hole 54. This allows the light interrupting segment 
53 of the paper absence detection lever 51 to remain between the light 
emitting element and the light receiving element of the paper absence 
sensor 52. When the paper sheets on the paper feed table 10 run out, the 
paper absence detection lever 51 pivots downwards owing to its own weight 
about the axis of the first rotary shaft 35 because no paper prevents the 
tip portion from fitting into the hole 54. As a result, the tip portion 
fits in the hole 54 defined in the paper feed table 10, causing the light 
interrupting segment 53 to move from the position between the light 
emitting element and the light receiving element of the paper absence 
sensor 52. Thus, no paper sheet on the paper feed table 10 is detected. 
(c) Feeding level detector 
The first rotary shaft 35 is also provided with a feeding level detection 
lever 55 and a feeding level detection release lever 56. Those levers 55, 
56 are away from the paper feed table 10 rightward with respect to the 
paper feeding direction b. More specifically, the feeding level detection 
lever 55 is supported at the centre thereof so as not to rotate forwardly 
and backwardly in relation to the first rotary shaft 35, whilst the 
feeding level detection release lever 56 is supported at the centre 
thereof so as to rotate forwardly and backwardly in relation to the same. 
On the downstream side of the feeding level detection lever 55 with 
respect to the paper feeding direction b, there is provided a feeding 
level sensor 57 composed of a light emitting element and a light receiving 
element for receiving light emitted from the light emitting element. When 
the top sheet of the paper sheet 5 stacked on the paper feed table 10 is 
at the feeding level X, a piece 58 formed at one end of the feeding level 
detection lever 55 is positioned between the light emitting element and 
the light receiving element of the feeding level sensor 57. On the 
downstream side of the feeding level detection release lever 56 with 
respect to the paper feeding direction b, there is provided a tension coil 
spring 59 for energizing the feeding level detection release lever 56 to 
pivot in a direction indicated by the arrow f of FIG. 4. On the upstream 
side of the feeding level detection release lever 56 with respect to the 
paper feeding direction b, there is provided an interlocking piece 60 
integrally formed with the feeding level detection release lever 56. When 
the tension coil spring 59 causes the pivoting of the feeding level 
detection release lever 56 in the direction of the arrow f, the 
interlocking piece 60 comes in contact with the underside of one end of 
the feeding level detection lever 55 to be interlocked therewith in order 
to raise the feeding level detection lever 55 in the direction of the 
arrow f. The feeding level detection release lever 56 is connected, at the 
downstream side thereof, to a plunger 61 which is actuated only during 
paper feeding and during feeding level detection, and releases the feeding 
level detection release lever 56 from the interlocking with the feeding 
level detection lever 55 by rotating the feeding level detection release 
lever 56 against the energizing force of the tension coil spring 59 in the 
opposite direction to the direction of the arrow f. When the plunger 61 is 
not operative (i.e., during a time when neither paper feeding nor feeding 
level detection are executed), the tension coil spring 59 energizes the 
feeding level detection release lever 56 to pivot so that the feeding 
level detection lever 55 is interlocked with the interlocking piece 60 of 
the feeding level detection release lever 56 and is raised in the 
direction of the arrow f as shown in FIG. 5. Then, the pick-up rollers 
38a, 38b etc. are raised by the first rotary shaft 35 so that they are 
suspended above the top sheet of the paper sheets stacked on the paper 
feed table 10. On the other hand, when the plunger 61 is operative (i.e., 
during paper feeding or during feeding level detection), the feeding level 
detection lever 55 is released from its raised condition, the raising 
being a result of from the interlocking by the interlocking piece 60 of 
the feeding level detection release lever 56. Then, the pick-up rollers 
38a, 38b are brought into contact with the top sheet of the paper sheets 
on the paper feed table 10 from above because of their own weight. At that 
time, if the piece 58 formed at one end of the feeding level detection 
lever 55 is positioned between the light emitting element and the light 
receiving element of the feeding level sensor 57, it is detected that the 
top sheet is at the feeding level X, and if not, it is detected that the 
top sheet is not at the feeding level X. 
There is a link 63 interposed between the casing 6 and the cover 7. The 
link 63 has projections 62a, 62b at both ends of one face thereof, and is 
pivotally supported on the cover 7 with the projection 62a. The projection 
62b is loosely inserted into a guide groove 64 defined in a vertical 
direction in the casing 6 side in such a manner that: as the cover 7 is 
opened in the direction of the arrow a of FIG. 2, the projection 62b is 
guided to move upwards from the bottom of the guide groove 64; and as the 
cover 7 is closed in the direction of the arrow a, the projection 62b is 
guided to move downwards from the top of the guide groove 64. The first 
rotary shaft 35 is provided with a flipping board 65 secured at the end 
thereof, the end being situated at the right hand with respect to the 
paper feeding direction b. As shown in FIG. 5, in the course of the upward 
movement of the projection 62b through the guide groove 64, the projection 
62b flips the flipping board 65 upwards as the projection 62b moves 
upwards, with the result that the first rotary shaft 35 rotates in the 
direction of the arrow f. Accordingly, the first rotary shaft 35 is 
rotated in the direction of the arrow f concomitantly with the opening of 
the cover 7. This rotation is transmitted to the pick-up rollers 38a, 38b 
through the supporting arms 40a, 40b and to the paper absence detection 
lever 51 engaged with the supporting arm 40b, so that the pick-up rollers 
38a, 38b and the paper absence detection lever 51 pivot upwards about the 
axis of the first rotary shaft 35. As a result, the pick-up rollers 38a, 
38b and the paper absence detection lever 51 are retracted from their 
respective positions above the paper feed table 10, which facilitates the 
operation of loading paper sheets onto the paper feed table 10 from above. 
The opening of the cover 7 turns an interlock switch off, thereby bringing 
the sensors and driving motors etc. into their inoperative conditions. 
The invention applied to a paper feeder of the separation type which is 
installed separately from the main body of an electrophotographic device 
has been particularly described hereinabove, but it is obvious that the 
invention may be applied to a paper feeder integral with the main body of 
an electrophotographic device. 
Although the above embodiment employs two pairs of pulleys 17a through 17d 
(17a' through 17d') provided at each of the sides (situated at the right 
and left of the paper feeding direction b) of the paper hopper, the 
pulleys in each pair being vertically aligned, and the two pairs being 
arranged along the paper feeding direction b, the invention is not 
necessarily limited to this. Alternatively, three pairs of pulleys may be 
provided on both sides. Further, four pairs of pulleys or more may be 
provided on both sides. 
The paper feed table 10 is held horizontal by the use of a pair of endless 
rubber belt 24, 24' in the above embodiment, but it is also possible to 
adopt such an arrangement that one endless rubber belt is used and a 
common rotary shaft is provided for a pair of opposite pulleys, for 
example, the pulleys 17b, 17b'. 
The endless wire ropes 18, 18' employed in the embodiment may be extended 
in the form of a ring, or wire ropes each of which is connected at the 
projections 16 (16') of the paper feed table 10 may be used. Instead of 
the endless wire ropes 18, 18', endless fabric ropes may be used. Although 
the endless rubber belt 24, 24' are employed in the embodiment, endless 
chains can be employed instead of those belts. 
The invention being thus described, it will be obvious that the same may be 
varied in many ways. Such variations scope of the invention, and all such 
modifications as would be obvious to one skilled in the art are intended 
to be included within the scope of the following claims.