Sheet feeding or delivering – Feeding – By means to convey sheet
Reexamination Certificate
1999-03-08
2001-03-27
Skaggs, H. Grant (Department: 3651)
Sheet feeding or delivering
Feeding
By means to convey sheet
C271S010110, C271S010130, C271S116000, C271S122000, C271S264000
Reexamination Certificate
active
06206368
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to paper transport devices applicable to document scanners, copying machines, printers, facsimile machines and like apparatus. More particularly, the invention pertains to paper transport devices in which paper, such as an original document or copying paper, is transported in a specified direction by at least one pair of rollers.
2. Description of the Background Art
Referring to
FIG. 1
, a conventional image forming apparatus, such as a copying machine or a facsimile machine, typically comprises a document tray
610
provided in an upper part of a main body
600
, a document feeder
620
which is provided at the right of the document tray
610
(as illustrated in
FIG. 1
) and has a top cover
621
, a scanner
630
provided beneath the document tray
610
, an optical unit
640
provided beneath the scanner
630
, an image forming unit
650
which is disposed beneath the optical unit
640
and includes a photosensitive drum
651
which produces a toner image from an original image exposed by laser light emitted from the optical unit
640
and transfers the toner image onto paper, a paper feed section
660
which is disposed beneath the image forming unit
650
and includes a paper cassette
661
, a fuser assembly
670
provided downstream of the paper feed section
660
, and a paper output section
680
provided downstream of the fuser assembly
670
, for example.
The original image is read, or scanned, in the following manner. An original document loaded on the document tray
610
is first transferred rearward (rightward as illustrated) as it is successively nipped by a plurality of roller pairs of the document feeder
620
. Then, the document feeder
620
reverses the feed direction of the document and ejects it back onto the document tray
610
. The scanner
630
scans the original image while the document is being transferred by the document feeder
620
.
If the document jams as it is transferred rearward by the document feeder
620
in the image forming apparatus thus constructed, it is necessary to open the cover
621
and remove the document from between the roller pairs located in an upper part of the document feeder
620
. If the document feeder
620
employs a multiple sheet feed assembly in which each successive sheet is separated and transported from multiple sheets of an original document stacked on the document tray
610
, for example, a jam could occur while a sheet is being transferred toward the rear side of the apparatus. Explained below is how this type of jam has conventionally been dealt with.
FIGS. 2
to
4
are diagrams showing a principal portion (multiple sheet feed assembly) of a conventional paper transport device. This paper transport mechanism is constructed such that a roller
643
f
rotatably mounted in a roller housing
647
can project outward and retract inward through an opening
647
b
formed in an upper surface of the roller housing
647
. In this construction, a cylindrical outer surface of the roller
643
f
is caused to partly protrude upward and push against another roller located above (not shown) to thereby grip and transport a sheet of paper. In the event of a paper jam, the roller
643
f
is retracted into the roller housing
647
so that the roller
643
f
is separated from the upper roller, making it possible to remove a sheet which has been seized between the rollers. The construction of this paper transport device is now described in further detail referring to
FIGS. 2
to
4
.
The roller housing
647
has a pair of side plates
647
a
attached to both ends, and a cover
648
which can be opened and closed is fitted to pivot pins
645
a
provided on both side plates
647
a.
As depicted in detail in
FIGS. 3 and 4
, the roller
643
f
is mounted on a roller shaft SF
1
which is fitted in vertically extending slots
647
c
formed in the side plates
647
a
attached to the opposite ends of the roller housing
647
so that the roller shaft SF
1
can move up and down. When the cover
648
is swung up about the pivot pins
645
a
, the cylindrical outer surface of the roller
643
f
which has partly protruded from the cover
648
through its opening
647
b
is fully retracted into the inner space of the roller housing
647
. More particularly, L-shaped levers
647
e
are provided inside the individual side plates
647
a
which are attached to the roller housing
647
, each L-shaped lever
647
e
being fitted swingably about a pivot pin
647
d
which is formed at an upper rear part of the corresponding side plate
647
a
, projecting from its inside surface, with one end of the L-shaped lever
647
e
extending toward the roller
643
f
and the other end directed downward. Each end of the roller shaft SF
1
is fitted in a hole
647
f
formed in one terminal portion of the L-shaped lever
647
e
that extends toward the roller
643
f
, while a spring
649
is hooked between a projecting pin
647
g
formed at the other terminal portion of the L-shaped lever
647
e
and a pin
648
d
formed on a fixing plate
648
c
, projecting inward from the inside surface of a rear part of the cover
648
. The roller shaft SF
1
fitted in the holes
647
f
formed in both side plates
647
a
is biased upward by springs
647
p
disposed below the roller shaft SF
1
at both ends thereof.
In this construction, when the cover
648
is closed as shown in
FIG. 3
(i.e., when the paper transport device is ready to feed the original document), the roller shaft SF
1
is pushed upward by the springs
647
p
and, therefore, the roller
643
f
is lifted and part of its cylindrical outer surface is exposed to the outside of the roller housing
647
. On the other hand, when the cover
648
is swung up about the pivot pins
645
a
as shown in
FIG. 4
, each fixing plate
648
c
of the cover
648
shifts rearward so that each spring
649
is pulled rearward and, thus, the downward-directed end (rear end) of each L-shaped lever
647
e
swings clockwise about the pivot pin
647
d
(as illustrated in FIG.
4
), overwhelming a pushing force exerted by the relevant spring
647
p
. As a consequence, the roller
643
f
is forced downward and the part of its cylindrical outer surface which has been exposed to the outside of the roller housing
647
is retracted into its inner space. Since the roller
643
f
is separated from its upper roller at this point, an operator can remove the sheet of the document jammed between the two rollers.
The paper transport device of the above-described construction is provided with complicated mechanisms on both sides of the roller
643
f
for moving the roller shaft SF
1
upward and downward in interlocked action with the opening and closing of the cover
648
. The result of this construction is an increase in overall costs of the paper transport device, and this is one of the factors of cost increase of the conventional image forming apparatus incorporating this type of paper transport device.
The foregoing discussion has focused on how a jam which occurs while the document feeder
620
is transferring a sheet of the original document toward the rear side of the apparatus is dealt with. Explained next is how a jam which occurs while a sheet of the document is being transferred forward is dealt with. When this type of jam has occurred, it is necessary to swing up the document tray
610
about its one side to expose a bottom part of the document feeder
620
and then remove the sheet which has jammed from between a pair of rollers located in the bottom part of the document feeder
620
. From this, it is recognized that the conventional paper transport device has required a very complicated procedure for dealing with this type of jam.
Although rollers of each roller pair are held in firm contact with each other in normal paper transport conditions, it is desirable to relieve the rollers of their firm contact when dealing with a jam. Then, after removing a sheet which has jammed in the paper transport device, the rollers of each roller pair must be brought back to firm c
Araishi Kuniaki
Aso Yutaka
Deguchi Masaki
Kakuta Masayuki
Kobayashi Hiroshi
Jordan and Hamburg LLP
Kyocera Mita Corporation
Skaggs H. Grant
LandOfFree
Paper transport device with one roller pair does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Paper transport device with one roller pair, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Paper transport device with one roller pair will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2509235