Sheet feeding or delivering – Feeding – By means to convey sheet
Reexamination Certificate
1999-08-25
2001-08-21
Skaggs, H. Grant (Department: 3651)
Sheet feeding or delivering
Feeding
By means to convey sheet
C271S272000
Reexamination Certificate
active
06276680
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a sheet feeding apparatus for feeding sheets and, more particularly, to a sheet feeding apparatus for feeding recording media in a recording apparatus having a function such as a printer, a photocopier, a facsimile machine, or the like.
2. Description of Related Art
Recording apparatuses having a function such as a printer, a photocopier, a facsimile machine, or the like, and recording apparatuses used for output devices for hybrid electronics apparatuses such as computers and word processing apparatuses or workstations are structured to record images on recording media such as sheet papers and plastic thin plates based on image information. The recording apparatuses can be categorized, based on the recording method, into the inkjet type, the wire dot type, the thermal type, the laser beam type, or the like.
In a recording apparatus of a serial type using a serial scanning method in which a main scanning is made in a direction intersecting with a feeding direction of the recording medium (subsidiary scanning direction), the entire recording medium is recorded by repeating the processes of recording images (main scanning) by a recording means mounted on a carriage traveling along a recording medium feeding the sheet in a fixed amount (pitch feeding) after images of one line are recorded, and subsequently recording images of the next line (main scanning) on the recording medium stopped again. On the other hand, in a line type recording apparatus which does recording only in the subsidiary scanning direction, the entire recording medium is recorded by repeating the processes of setting a recording medium at a prescribed recording position. feeding the recording medium in a predetermined amount (pitch feeding) after the one line recording is made at one time, and recording the next line at one time.
FIG. 11
shows a perspective view showing a conventional inkjet recording apparatus. In the inkjet recording apparatus, the recording medium fed by a feeding apparatus
101
is held by a platen
122
constituted such that a feeding surface in the printing area is made flat and delivered by a delivery means
133
formed on a downstream side in the feeding direction after images are formed by a recording head
124
.
The delivery means
133
includes a delivery roller
134
, and a special paper pressing member (e.g., a spur having a gear teeth on circumferential surface)
136
d
located facing to the delivery roller
134
for feeding the recording medium in pressing the recording medium through point contacts. Rotation of those members makes the recording medium fed with applied inks not yet fixed right after printing.
The delivery roller
134
is freely rotatable where each opposite end of the shaft is attached to a bearing formed at the platen
122
. A recording medium feeding portion of the roller is rounded with a material such as a rubber or sponge-like material thereby rendering the recording medium hardly slip when fed.
The drive force given to the delivery roller
134
is transmitted from a paper feeding roller
132
via a transmission roller
135
attached to the platen. The transmission roller
135
is urged as to press both of the paper feeding roller
132
and the delivery roller
134
by an elastic shaft.
The spur
136
has a circumferential portion with gear teeth, which tend not to leave pressed marks or ink marks on the recording medium, so that such a spur is widely used for an inkjet recording apparatus.
The spur
136
functions for maintaining the printing quality in suppressing cockling of the recording medium in a direction perpendicular to the feeding direction when recording is made with high recording density or high duty and for protecting the recording head
124
by avoiding contacts between the recording head
124
and the recording medium.
The spur
136
is mounted on an attachment member with the elastic shaft go that the spur can move in substantially a perpendicular direction with respect to the feeding surface for the recording medium according to the thickness of the recording medium, and the attachment member may be formed with a restricting means for restricting the movement of the elastic shaft to restrict the movement of the spur
136
in substantially the perpendicular direction. This is for suppressing the movement of the spur
136
within a predetermined distance where the recording media is fed in a multiple number from the feeding apparatus
101
(duplicated feeding) to prevent the elastic shaft as a rotary shaft of the spur
136
from receiving damages.
With the conventional inkjet recording apparatus, as described above, no restricting means is provided for restricting the movement of the spur
136
, and even where such a restricting means is provided, the spur
136
is restricted by restricting the position of the elastic shaft serving as the rotary shaft of the spur
136
by means of the restricting means.
With the latter structure, however, the elastic shaft may come in contact with the restricting means where the extremely thick recording medium is fed from the feeding apparatus
101
or where multiple recording media are fed from the feeding apparatus
101
, thereby exerting large shear force to the elastic shaft, and possibly damaging the elastic shaft.
Furthermore, because the restricting means for restricting the movement of the spur
136
by restricting the movement of the elastic shaft is provided only in substantially the perpendicular direction with respect to the feeding surface of the recording medium, the elastic shaft may be damaged upon exertion of shear force in a direction that the recording medium is pulled out to the elastic shaft serving as the rotary shaft of the spur
136
when, e.g., the recording medium is pulled out due to occurrence of jamming of the recording media. Therefore, it is required to make the elastic shaft itself stronger, and this requirement may result in restriction on design.
As a structure to pull out the recording medium without exerting load to the spur
136
during paper jamming, a spur
136
may be conceivably attached to a cover portion that can be opened and closed as shown in
FIG. 11
, but in such a case, the structure may bring higher production costs and restriction on accuracy in assembling parts.
It is an object of the invention to provide a sheet feeding apparatus capable of preventing an elastic shaft of a spur from receiving damages due to force in multiple directions exerted to the spur during paper jamming or the like.
SUMMARY OF THE INVENTION
A representative structure of the invention in order to accomplish the above objects includes a first feeding rotary body for feeding sheets, a second feeding rotary body located opposing the first feeding rotary body for feeding the sheets between the second feeding rotary body and the first feeding rotary body upon pressing the sheets, an elastic shaft serving as a rotary center of the second feeding rotary body for urging the second feeding rotary body toward the first feeding rotary body, and restricting means for restricting movements of the second feeding rotary body in multiple directions by contacting with the second feeding rotary body.
According to the above structure, since the restricting means restricts movements of the second feeding rotary body in multiple directions by contacting with the second feeding rotary body, the elastic shaft serving as a rotary shaft of the second feeding rotary body can be prevented from inflicting damages because the movable range of the second feeding rotary body can be restricted not only in a substantially perpendicular direction with respect to the sheet feeding surface but also during a paper jamming, by, e.g., restricting the movements of the second feeding rotary body in a sheet thickness direction and in a direction toward an upstream side in the sheet feeding direction by means of the restricting means.
The second feeding rotary body is made of a tooth portion for feeding the sheets by pressing the sheets at point
Sonoda Shinya
Tanaka Hiroyuki
Yanagi Haruyuki
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Skaggs H. Grant
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