Sheet feeding or delivering – Feeding – Separators
Reexamination Certificate
2000-03-01
2001-09-25
Valenza, Joseph E. (Department: 3651)
Sheet feeding or delivering
Feeding
Separators
C110S120000, C110S159000, C110S159000, C110S159000, C110S159000, C073S650000, C073S065070, C310S311000, C310S31300R
Reexamination Certificate
active
06293539
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 11-155136, filed Jun. 2, 1999, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
This invention relates to a rotating or pivoting apparatus for use in, for example, a copy machine for picking up and transferring a medium such as a copy paper sheet.
There is a medium feeding apparatus for use in, for example, a copy machine, in which sheets of a medium are stacked on a backup plate, and picked up one by one in the order beginning from an uppermost one in accordance with the rotation of a pickup roller incorporated in the apparatus. The backup plate is urged upward by a spring member, thereby pressing the uppermost medium member against the pickup roller. The pickup roller has its surface coated with a rubber member and hence has a frictional force.
Since the sheets of the medium stacked on the backup plate have substantially the same frictional force, it is possible that other sheets placed under the uppermost one in contact therewith will be picked up simultaneously with the uppermost one during the rotation of the pickup roller. To avoid this, a separating mechanism is provided on the medium-picking side of the pickup roller for separating the sheets of the medium from each other. The separating mechanism includes a forwarding roller and an interrupting roller opposed to the forwarding roller. The forwarding roller and the pickup roller are synchronous with each other and rotate in the same direction. The interrupting roller is fixedly opposed to the forwarding roller, with a gap corresponding to one sheet interposed therebetween.
When a plurality of sheets of the medium in a stacked state have been picked up by the pickup roller, only the uppermost one passes through the gap between the forwarding roller and the interrupting roller, while the remaining sheets of the medium are interrupted by the interrupting roller. Further, each sheet of the medium forwarded in accordance with the rotation of the forwarding roller is sensed by a sensor, and the rotation of the pickup roller is stopped depending upon the sensing result. After each sheet of the medium passes the sensor, the sensor determines that each sheet has been sent to a later process, thereby rotating the pickup roller to pick up the next sheet of the medium.
Medium feeding apparatuses constructed as above are widely used for various purposes. Accordingly, these apparatuses treat various types of mediums that have different thicknesses or friction factors, or may be easily worn or deformed.
In light of the above, an apparatus is demanded which can reliably pick up and transfer various types of mediums one by one, and at the same time can execute a high-speed operation or can deal with a great amount of mediums.
However, in the prior art, each medium is pressed with a great force of, for example, about 1-5 N in light of, for example, deformation of each medium. This force is much higher than that necessary for forwarding mediums.
In general, when forwarding stacked sheets of a medium using a frictional force, the greater the force applied to each sheet to press it against the pickup roller, the larger the number of sheets to be forwarded simultaneously. Therefore, it is necessary to minimize the pressing force applied to each sheet. If, however, the pressing force is too small, slippage may occur between each sheet and the pickup roller. To avoid this, the pressing force applied to a medium is set at a high value in the prior art. As a result, it is possible that a plurality of sheets of a medium are simultaneously picked up by the pickup roller, thereby increasing the load on the separating mechanism that separates sheets of a medium from each other. In other words, the separating mechanism may not separate the sheets reliably.
When the pickup roller simultaneously picks up a plurality of sheets of a medium, it is desirable that a dedicated sensor should promptly sense it to thereby stop the rotation of the pickup roller. However, there is no space between the pickup roller and the separating mechanism, and hence such a sensor cannot be provided. This being so, a plurality of sheets of a medium, if simultaneously picked up, cannot promptly be sensed and the pickup roller cannot be stopped.
Since in the prior art, the rotation of the pickup roller is stopped on the basis of a signal output from a sensor provided downstream of the separating mechanism, large portions of sheets of a medium have been forwarded when the rotation of the pickup roller has been stopped.
BRIEF SUMMARY OF THE INVENTION
The present invention has been developed in light of the above, and aims to provide a medium-feeding apparatus capable of reliably feeding sheets of a medium one by one while applying a small force to the sheets to press them against a pickup roller.
The present invention also aims to provide a rotating or pivoting apparatus capable of promptly sensing slippage if it occurs between the outer ring of a pickup roller and a to-be-treated object during rotation or pivoting of the outer ring, thereby controlling the rotation or the pivoting of the outer ring.
According to a first aspect of the invention, there is provided a rotating or pivoting apparatus comprising:
an inner ring rotating or pivoting when power is transmitted thereto from a driving source;
an outer ring located outside the inner ring and rotating or pivoting when power is transmitted thereto from the inner ring, thereby transmitting power to a to-be-treated medium; and
sensing means provided between the inner ring and the outer ring for sensing vibration of the outer ring to thereby sense slippage between the outer ring and the to-be-treated medium.
According to a second aspect of the invention, there is provided a medium feeding apparatus comprising:
mounting means for mounting thereon a medium in a stacked manner;
a pickup roller for picking up each of the medium while it rotates or pivots;
a driving source for driving the pickup roller; and
driving means for moving the mounting means to press the medium against the pickup roller;
sensing means provided in the pickup roller for sensing a change in fine acceleration of the pickup roller to thereby sense slippage between the pickup roller and the medium; and
control means for executing control so as to drive the driving means to thereby vary a force for pressing the medium against the pickup roller, when the sensing means has sensed slippage between the pickup roller and the medium.
According to a third aspect of the invention, there is provided a medium feeding apparatus comprising:
mounting means for mounting thereon a medium in a stacked manner;
a pickup roller for picking up each of the medium while it rotates or pivots;
a driving source for driving the pickup roller; and
driving means for moving the mounting means to press the medium against the pickup roller;
sensing means provided in the pickup roller for sensing a change in fine acceleration of the pickup roller to thereby sense slippage between the pickup roller and the medium; and
control means for executing control so as to drive the driving means to thereby vary a force for pressing the medium against the pickup roller, when the sensing means has sensed slippage between the pickup roller and the medium,
wherein the pickup roller includes:
an inner ring rotating or pivoting when power is transmitted thereto from the driving source; and
an outer ring located outside the inner ring and rotating or pivoting when power is transmitted thereto from the inner ring, thereby transmitting power to the medium, and
the sensing means is provided between the inner ring and the outer ring for sensing a change in fine acceleration of the outer ring to thereby sense slippage between the outer ring and the medium.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned
Fukatsu Kunio
Inoue Katsumi
Obama Masao
Kabushiki Kaisha Toshiba
Pillsbury & Winthrop LLP
Ridles Richard
Valenza Joseph E.
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