Sheet feeding or delivering – Feeding – Separators
Reexamination Certificate
2000-05-10
2001-05-08
Bollinger, David H. (Department: 3651)
Sheet feeding or delivering
Feeding
Separators
C271S167000
Reexamination Certificate
active
06227535
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a printing machine, and more particularly, to an automatic sheet feeder of a printing machine having a maximized sheet feeding efficiency and durability by minimizing the frictional load during the feeding operation thus by preventing the occurrence of stepping out and abrasion of respective components or paper double feeding and slippage.
2. Description of the Prior Art
Generally, an automatic sheet feeder (ASF) is an essential part of a printing machine which picks up each sheet of paper and conveys the picked sheet of paper to a printing section.
FIGS. 1 and 2
show one example of such an automatic sheet feeder.
Conventionally, the so-called “compensator type ASF” has been used in which gears
1
driven by a driving motor (not shown) drive a rotational shaft
2
, to rotate a compensator
3
disposed on the rotational shaft
2
toward a paper loading section
4
. Being rotated toward the paper loading section
4
, the compensator
3
comes into contact with the first sheet of paper P loaded in the paper loading section
4
, and picks up and feeds the first sheet of paper P through a paper feeding roller
5
which is mounted on an end of the compensator
3
and rotated by the driving force transmitted from the rotational shaft
2
.
Here, paper pick up devices in almost all kinds of automatic sheet feeders (inclusive of the above-described automatic sheet feeder) pick up and feed a sheet of paper P by the rotational force of the paper feeding roller
5
in a state that the paper feeding roller
5
is pressed into contact with a paper friction pad
6
which is made of cork material and attached on the bottom of the paper loading section
4
.
Since the conventional automatic sheet feeder
10
does not have any means for detecting the presence of the paper P in the paper loading section
4
, many problems have been caused by the printing operation started by the printing command in the absence of the paper P in the paper loading section
4
.
More specifically, when the printing operation is carried out in the absence of paper P, due to the frictional force generated between the rotating paper friction pad
6
and the paper feeding roller
5
, noise is produced between the rotating paper friction pad
6
and the paper feeding roller
5
, and finally, faulty sheet feeding operation of the printing machine such as paper double feeding or slippage occurs as the paper feeding roller
5
and the paper friction pad
6
, which are capped by a rubber material, are quickly worn out.
Further, the overload caused by the frictional force between the paper feeding roller
5
and the paper friction pad
6
may also cause stepping out of the components such as the motor and gears
1
, etc., damaging the printing machine.
The above-mentioned problems shorten the life span of the printing machine, deteriorating the reliability which results in user dissatisfaction.
SUMMARY OF THE INVENTION
The present invention has been developed to overcome the above-mentioned problems of the prior art, and accordingly, it is an object of the present invention to provide an automatic sheet feeder of a printing machine capable of minimizing a friction load between a paper feeding roller and paper friction pad during a feeding operation in the absence of paper, thus keeping the high feeding efficiency for a long period of time by preventing faulty feeding of paper such as paper double feeding and slippage, and thus lengthening the life span of the printing machine by preventing stepping out or abrasion of the components.
In order to accomplish the above-mentioned object, an automatic sheet feeder of a printing machine includes a paper friction pad section and a paper feeding roller for feeding a sheet of paper by a rotational pressing force exerted between the paper friction pad section and the paper feeding roller, and an idle pad roller formed on the paper friction pad section for being rotated in contact with the paper feeding roller by the rotational pressing force exerted on the paper feeding roller in absence of paper in the paper loading section.
The automatic sheet feeder further includes an elastic member formed on the paper friction pad section for elastically controlling the rotational movement of the idle pad roller in contact with the idle pad roller while the idle pad roller is rotated by the rotational pressing force of the paper feeding roller.
The idle pad roller is positioned slightly lower than the bottom surface of the paper loading section in a manner that the rotational shaft thereof is inserted into shaft guides which penetrate in both sides of the paper friction pad section to be elastically supported by the elastic member.
Accordingly, during the feeding operation, the idle pad roller and the paper feeding roller do not make contact in the presence of paper, while the idle pad roller and the paper feeding roller contact with each other in the absence of paper.
The elastic member includes a space formed in the center for receiving the idle pad roller, and a plate spring having a pair of elastic supports formed on both sides of the space and are elastically supported on the rotational shaft at both sides of the idle pad roller.
REFERENCES:
patent: 5938190 (1999-08-01), Campbell et al.
patent: 5938355 (1999-08-01), Suzuki
patent: 5971390 (1999-10-01), Caspar et al.
Bollinger David H.
Bushnell , Esq. Robert E.
Samsung Electronics Co,. Ltd.
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