Typewriting machines – Sheet or web – Including sheet guide
Reexamination Certificate
1999-09-29
2003-01-07
Yan, Ren (Department: 2854)
Typewriting machines
Sheet or web
Including sheet guide
C400S625000, C271S188000, C271S209000
Reexamination Certificate
active
06503011
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recording apparatus for performing the recording operation of a sheet member conveyed by a conveying means using a recording means.
2. Related Background Art
In an image forming apparatus using a conventional ink jet system, an image designated on a sheet of recording paper is generally reproduced as an ink image by cooperatively performing an operation for conveying the recording paper sheet in a subscanning direction, discharging control of a recording head for discharging ink to the recording paper sheet, and an operation for reciprocating the recording head in a main scanning direction (a direction perpendicular to the subscanning direction).
When the distance between a paper face and the recording head is excessively widened, the accuracy of an attaching position of an ink droplet discharged from the recording head is reduced so that the image is disturbed. Therefore, this distance is shortened as much as possible. However, in the ink jet recording system, the image is formed by discharging the ink having water as a main component to paper. Therefore, the paper is expanded and irregular “wrinkles” are caused. The paper face approaches the recording head by these “wrinkles” so that the paper face is rubbed by the recording head and the image is disturbed.
Therefore, a recording apparatus having an irregularity forming discharging portion as a means for controlling a generating degree of the “wrinkles” in the recording paper sheet is already proposed as a countermeasure for the rubbing of the recording paper sheet and the recording head caused by the generation of “wrinkles” in the recording paper sheet.
FIG. 10
is a cross-sectional view showing the irregularity forming discharging portion in the conventional recording apparatus.
As shown in
FIG. 10
, the irregularity forming discharging portion in the conventional recording apparatus is constructed by a conveying roller
101
, a pinch roller
102
, a platen
104
and a paper discharging roller
105
. The conveying roller
101
conveys a recording paper sheet S to a portion below an ink discharging portion of the recording head
103
. The pinch roller
102
is rotated by the conveying roller
101
and presses against the conveying roller
101
and presses the recording paper sheet S against the conveying roller
101
. The platen
104
is opposed to the recording head
103
and supports the recording paper sheet S. The paper discharging roller
105
discharges the recording paper sheet S after printing.
Plural ribs
104
a
are arranged at an interval from 20 to 30 mm in the irregularity forming discharging portion of the platen
104
. The recording paper sheet S is supported on an upper face of each of these ribs
104
a
. A height of each rib
104
a
is set such that the gas between the recording head
103
and the recording paper sheet S supported on the upper face of the rib
104
a
is minimized. A portion of the rib
104
a
opposed to the recording head
103
is arranged in parallel with the ink discharging portion of the recording head
103
. An upstream side portion of the rib
104
a
in a conveying direction of the recording paper sheet in the vicinity of the conveying roller
101
is formed in a taper shape in which a height of this upstream side portion is gradually increased from a low position to the height of the upper face along the conveying direction of the recording paper sheet. In contrast to this, a portion of the platen
104
except for the rib
104
a
is formed such that the height of this portion is lower by about 2 mm than the upper face of the rib
104
a.
An axis of the pinch roller
102
is arranged in a position shifted by about 1 to 2 mm on a downstream side in the conveying direction from an axis of the conveying roller
101
. Thus, an end tip of the conveyed recording paper sheet S hits against the taper portion of the rib
104
a
and the recording paper sheet S is then pressed against the upper face of the rib
104
a
. The paper discharging roller
105
is formed in a shape in which a rubber portion
105
a
coming in contact with the recording paper sheet S is divided in an axial direction of the paper discharging roller
105
. Each rubber portion
105
a
is arranged in a position conforming to each rib
104
a
of the platen
104
in the conveying direction of the recording paper sheet S.
In accordance with the recording apparatus constructed above, the recording paper sheet S is conveyed while the recording paper sheet S is pressed against the upper face of the rib
104
a
. At this time, a portion of the recording paper sheet S not supported by the rib
104
a
is pushed into a slightly low portion between ribs
104
a
adjacent to each other. In this state, when ink is discharged from the recording head
103
to the recording paper sheet S, the recording paper sheet S is expanded by water of the ink so that an expanded portion further enters a low portion between the ribs
104
a
. As a result, a portion of the recording paper sheet S supported on the upper face of each rib
104
a
becomes “convex”, and a portion of the recording paper sheet S between ribs
104
a
adjacent to each other becomes “concave”. Namely, irregularities having a corrugated plate shape in the main scanning direction are formed in the recording paper sheet S to which the ink is discharged. At this time, the gap between the recording paper sheet S and the recording head
103
is minimized in a portion (convex portion) supported on the upper face of the rib
104
a
. Accordingly, it is possible to prevent the paper face S and the recording head
103
from being rubbed. Thus, the recorded recording paper sheet S is conveyed and discharged outside the recording apparatus. The above irregularities are not formed in the subscanning direction in the recording paper sheet S recorded by discharging the ink.
As mentioned above, the height of each rib
104
a
is set such that the gas between the recording head
103
and the recording paper sheet S supported on the upper face of the rib
104
a
is minimized. Thus, dispersion in a gap difference of the irregularities of the recording paper sheet S can be set to lie within the range of an allowing gap amount at a time of the ink discharging operation of the recording head
103
so that a preferable image can be formed.
A fixing time of the ink to the paper face is required to form the image by discharging the ink to the paper face. However, when a printing speed of the recording apparatus is increased, the next recording paper sheet is discharged before the ink is fixed to the printed recording paper sheet discharged to the discharging portion. Accordingly, an end tip or a rear face of a subsequent recording paper sheet rubs an ink image of the recording paper sheet already discharged so that there is a fear of image disturbance.
Therefore, another recording apparatus is conventionally proposed. In this recording apparatus, a supporting member for supporting both ends of the subsequent recording paper sheet is arranged to prevent the subsequent recording paper sheet from being rubbed by the recording paper sheet already discharged to the discharging portion while the printed recording paper sheet is conveyed and the subsequent recording paper sheet is printed. Fixation of the ink to the recording paper sheet already discharged to the discharging portion is completed by natural drying while an image is printed on the subsequent recording paper sheet. Thus, the subsequent recording paper sheet can be discharged onto the recording paper sheet already discharged.
FIG. 11
is a cross-sectional view showing another conventional recording apparatus.
FIG. 12
is a perspective view showing a supporting member in the conventional recording apparatus shown in FIG.
11
.
As shown in
FIG. 11
, the conventional another recording apparatus is constructed such that a recording paper sheet fed by a paper feed means
111
is conveyed by a conveying portion
112
to a portion below a recording head
113
and is reco
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Yan Ren
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