Sheet paper attracting system

A paper sheet supplying system including a paper sheet attracting unit for attracting a paper sheet for feeding purposes, and a piled sheet feeding prevention unit which confronts the paper sheet attracting unit at a preselected position. When more than one sheet is attracted by the paper sheet attracting unit, the piled sheet feeding preventing unit removes the paper sheet or sheets from the sheet attracted by the paper sheet attracting unit so that only one sheet is accurately fed.

BACKGROUND OF THE INVENTION 
The present invention relates to a sheet paper attracting system for use in 
a sheet paper feeding system of a copying machine, a facsimile system, a 
printing machine, etc. 
The present invention relates, more particularly, to a piled feeding 
preventing system in a sheet paper feeding system. 
Various types of sheet paper feeding systems have been developed for 
supplying a paper sheet from a storing section wherein a plurality of 
sheets are stacked. In such a system it must be ensured that one sheet of 
paper is transferred at a desired time. It is not desirable that the 
transferred paper includes more than one sheet piled up. 
To prevent piled feeding, one of the conventional systems includes a catch 
for separating the paper sheets at one corner thereof. This mechanism does 
not work well when the attracting force between the sheets is considerably 
strong. Furthermore, the catch may damage the surface of the paper sheet. 
Another conventional system includes a separating roller which rotates in 
the reverse direction. This type of system does not work well when the 
frictional condition of the separating roller varies during a long usage 
time. Furthermore, an accurate adjustment is required depending on the 
thickness of the paper sheet. Moreover, it is clear that the separating 
roller may damage the surface of the paper sheet. 
Accordingly, an object of the present invention is to provide a novel paper 
feeding system which prevents the piled feeding of the paper sheets. 
Another object of the present invention is to provide a paper sheet 
attracting system which ensures an accurate feeding without damaging the 
surface of the paper sheeet. 
Other objects and further scope of applicability of the present invention 
will become apparent from the detailed description given hereinafter. It 
should be understood, however, 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. 
To achieve the above objects, pursuant to an embodiment of the present 
invention, a paper sheet attracting system is provided for attracting a 
paper sheet through the use of a suction air force. A piled feeding 
preventing system is provided in a manner that the piled feeding 
preventing system confronts the paper sheet attracting system when the 
paper sheet attracting system attracts the paper sheet. The piled feeding 
preventing system functions to attract the paper sheet attracted by the 
paper sheet attracting system through the use of a section air force. 
In a preferred form, the attracting force created by the piled feeding 
preventing system is selected lower than the attracting force created by 
the paper sheet attracting system, and the attracting force created by the 
piled feeding preventing system is selected greater than the attracting 
force formed between the adjacent two paper sheets.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
The piled sheet feeding preventing system of the present invention is 
constructed to cooperate with a sheet paper attracting system such as 
disclosed in my copending application, SHEET PAPER ATTRACTING SYSTEM, U.S. 
application Ser. No. 464,377 which claims priority based on Japanese 
patent application No. 57-20467 which was filed in Japan on Feb. 10, 1982. 
The piled sheet feeding preventing system of the present invention includes 
a suction air casing 1 having a pressure chamber 2 formed therein. Air 
intake openings 3 are formed at desired sections in the suction air casing 
1. A rotating shaft supporting plate 4 is secured to the bottom surface of 
the suction air casing 1, and a rotating shaft 5 is fixed to the rotating 
shaft supporting plate 4. The rotating shaft 5 is rotatably supported by a 
bearing member 6 which is provided on a drive table 7. Accordingly, the 
suction air casing 1 is rotatable about the rotating shaft 5 as shown by 
an arrow A in FIG. 1. Stopper members (not shown) are provided for 
determining the rotating angle of the suction air casing 1 about the 
rotating shaft 5. 
The above-mentioned unit is slidably (in the direction shown by an arrow B) 
mounted on a slide shaft 9. More specifically, a slider 8 is secured to 
the drive table 7. The slider 8 is mounted on the slide shaft 9 which is 
secured to a slide shaft supporting plate 10. A motor 11 is secured to the 
drive table 7 via a motor securing plate 14 for driving the unit including 
the suction air casing 1. 
The above-mentioned rotating operation of the suction air casing 1 is 
controlled by an ON/OFF operation of a solenoid 16. The solenoid 16 is 
secured to a solenoid supporting plate 17 and is connected, via a latch 
19, to a latch angle 18 which is fixed to the bottom surface of the 
suction air casing 1. The above-mentioned sliding operation is driven by 
the motor 11 via gears 15 supported by a gear supporting plate 13. The 
suction air casing 1 is communicated with a suction blower (not shown) 
through a duct 20. 
An operational mode of the piled sheet feeding preventing system of FIGS. 1 
and 2 will be described with reference to FIGS. 3, 4, 5 and 6. 
As already discussed above, the piled sheet feeding preventing system of 
the present invention cooperates with a paper sheet attracting system 21. 
An example of the paper sheet attracting system is disclosed in my 
copending application, "SHEET PAPER ATTRACTING SYSTEM" which claims the 
priority from a Japanese patent application No. 57-20467 (Our Reference 
2010-US,GER-T). 
When a paper sheet feed initiation is instructed, a paper sheet supporting 
table 23 is driven to shift upward in the direction shown by an arrow C in 
FIG. 3 so that an uppermost sheet 25' in paper sheets 25 stacked on the 
paper sheet supporting table 23 contacts the paper sheet attracting system 
21. At this moment, the piled sheet feeding preventing system is held at a 
stand-by position and the suction operation is not performed by the piled 
sheet feeding preventing system. 
Then, the suction operation of the paper sheet attracting system 21 is 
initiated to attract the uppermost sheet 25'. The paper sheet attracting 
system 21 is rotated as shown in FIG. 4. At this moment, the suction 
operation of the piled sheet feeding preventing system is initiated, and 
the piled sheet feeding preventing system is moved to a position near the 
rear surface of the uppermost sheet 25'. Thereafter, the piled sheet 
feeding preventing system is driven backward to a preselected position as 
shown by the solid line in FIG. 4. The forward and backward movement of 
the piled sheet feeding preventing system is controlled by a position 
control circuit 71 shown in FIG. 7. When the piled sheet feeding 
preventing system is held as shown by the solid line in FIG. 4, a 
determination is carried out as to whether any sheets are attracted by the 
piled sheet feeding preventing system. This determination is conducted by 
a sheet attract detection circuit 72 through the use of a detection of the 
variation of the load current of the suction blower. 
The attracting force created by the piled sheet feeding preventing system 
is selected slightly lower than that of the paper sheet attracting system 
21. Therefore, the uppermost sheet 25' caught by the paper sheet 
attracting system 21 will not be separated from the paper sheet attracting 
system 21. If the paper sheet is not attracted by the piled sheet feeding 
preventing system, only one sheet (the uppermost sheet 25') has been 
correctly attracted by the paper sheet attracting system 21. At this 
moment, the piled sheet feeding preventing system is rotated to depress 
the following sheets as shown in FIG. 6. 
When more than one sheet has been attracted by the paper system attracting 
system 21, the next sheet (sheets) 25" is attracted by the piled sheet 
feeding preventing system as shown in FIG. 4. That is, the attracting 
force of the piled sheet feeding preventing system is selected greater 
than the attracting force created between adjacent two sheets. When the 
sheet attract detection circuit 72 detects that the piled sheet feeding 
preventing system attracts one or more sheets, the suction operation is 
interrupted, and the piled sheet feeding preventing system is returned to 
the initial stand-by position as shown by the dotted line in FIG. 5, 
thereby allowing the sheets to return to the paper sheet supporting table 
23. After a predetermined time has passed, the above-mentioned operation 
is repeated to again attract the piled sheets 25" if any. 
When the sheet attract detection circuit 72 does not develop a signal 
indicating that the paper sheet is not attracted by the piled sheet 
feeding preventing system, because the paper sheet attracted by the piled 
sheet feeding preventing system is again attracted by the uppermost sheet 
25', even when the above-mentioned operation is repeated by several times, 
an attracting force control circuit 73 is enabled to increase the 
attracting force created by the piled sheet feeding preventing system. 
When the next sheets 25" can not be removed at all, the system operation 
is interrupted and an alarm device is enabled. 
With the above-mentioned operation, when only the uppermost sheet 25' is 
attracted by the paper sheet attracting system 21, a sheet feeding 
mechanism 22 is enabled as shown in FIGS. 5 and 6 to transfer the 
uppermost sheet 25' along a guide 24 in the direction shown by an arrow E. 
While the sheet feeding operation is conducted, the piled sheet feeding 
preventing system depresses the paper sheets 25 stacked on the paper sheet 
supporting table 23. When the sheet feeding operation is completed, the 
piled sheet feeding preventing system is returned to the initial stand-by 
position as shown in FIG. 3. 
The invention being thus described, it will be obvious that the same may be 
varied in many ways. Such variations are not to be regarded as a departure 
from the spirit and scope of the invention, and all such modifications are 
intended to be included within the scope of the following claims.