Electrophotography – Document handling
Reexamination Certificate
2003-04-09
2004-05-11
Ngo, Hoang (Department: 2852)
Electrophotography
Document handling
C399S107000
Reexamination Certificate
active
06735413
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a sheet operative member such as a conveyance roller for contacting and conveying sheets by frictional force thereof, and a separation pad for separating sheets, to a sheet conveying apparatus using this member, and to an image processing apparatus such as an electrophotographic photocopier, a printer, a word processor, and a facsimile machine.
2. Description of Related Art
Image forming apparatuses such as printers and photocopiers using one of electrophotographic methods or other recording methods are widely available these days. In accordance with tendency of higher performance and longer duration of the apparatuses, improvements in feeding accuracy and durability in conveyance rollers used in the image forming apparatus are required. Separation pads used for the image forming apparatuses also require in the same manner improvements in separation accuracy and durability.
A conventional conveyance roller
100
is formed, as shown in
FIG. 8
, of a core metal
101
made of a metal or molded material and a cylindrical rubber portion
102
made of a rubber material such as EPDM (ethylene propylene rubber), CR rubber (chloroprene rubber), silicone rubber, or urethane rubber for contacting a recording sheet and conveying the recording sheet by frictional force. Polishing is made in arrow C or D direction shown in
FIG. 8
on a cylindrical surface
102
a
of the cylindrical rubber portion
102
.
A separation pad
103
shown in
FIG. 9
is formed of a rubber material such as EPDM, CR rubber, silicone rubber, or urethane rubber in substantially the same manner as the conveyance roller
100
described above and is constituted of a rubber portion
104
in contact with the conveyance roller, and a holder
105
holding the rubber portion
104
. Polishing is made in arrow E or F direction shown in
FIG. 9
on a rubber surface
104
a
of the rubber portion
104
.
The conventional conveyance roller and the conventional separation pad, however, raised the following problems.
Where the conventional conveyance roller conveys a recording sheet, paper powder generated from surfaces of the recording sheets may attach to the cylindrical surface of the conveyance roller according to an increased conveyance sheet number of the recording sheets, thereby slipping in recording sheet conveyance with lowered frictional force of the conveyance roller, and thereby raising a problem of impaired images and jamming occurrences. To extend the product duration of the apparatus body, users were required to make cleaning, or the apparatuses had a structure that the users can replace the conveyance rollers. As a result, this invited lowered usability and increased costs from additional parts in a structure that the conveyance roller is replaceable.
Where the conventional separation pad separates and conveys the recording sheets, paper powder generated from surfaces of the recording sheets may attach to the surface of the separation pad according to an increased conveyance sheet number of the recording sheets, thereby raising a problem of doubly feeding of the recording sheets due to lowered frictional force of the separation pad. Therefore, substantially the same problem is raised as in the case of the conveyance roller.
SUMMARY OF THE INVENTION
This invention is to solve the above problems. It is an object of the invention to provide a sheet operative member such as a conveyance roller or the like avoiding lowered frictional force due to paper powder attachments, realizing highly durable roller members or the like, and having an inexpensive structure of a longer duration with maintenance free and to provide a sheet conveying apparatus and an image processing apparatus using the member.
A preventative structure according to the invention to accomplish the above object is a sheet operative member contacting a sheet and conveying with frictional force the sheet or separating, including a plurality of protrusions on an operative surface with the sheet; and each of the protrusions including: a standing portion standing up from the operative surface; and a spherical portion disposed at a distal end of the standing portion.
Where a conveyance roller is structure of the sheet operative member thus structured, the sheet is conveyed with frictional force from contact with the spherical portions of the protrusions of the conveyance roller. Because the contact between the conveyance roller and the sheet is at the spherical portion at the distal end of the protrusion, paper powder or the like generated from the sheet surfaces is not attached to the spherical portions of the protrusions but deposited in an attaching manner on a circumferential surface of the conveyance roller. This realizes a conveyance roller having property of stable conveyance and high durability. The same advantages can be provided in a case where the sheet operative member is used as a separation pad.
According to the invention, where fine protrusions described above are formed to the sheet operative member, a sheet apparatus is hardly affected from paper powder or the like generated from the sheet surfaces and can enjoy a stable sheet processing performance. Therefore, where structured in use of the sheet operative member described above, the sheet apparatus such as a sheet conveying apparatus can be provided with maintenance free and inexpensive costs.
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patent: 5752149 (1998-05-01), Yuza et al.
patent: 5927702 (1999-07-01), Ishii et al.
patent: 6070867 (2000-06-01), Tsurumi et al.
Kobayashi Ken-ichi
Yuza Akira
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