Typewriting machines – Sheet or web – Including friction-feed means
Reexamination Certificate
1999-09-21
2002-07-16
Colilla, Daniel J. (Department: 2854)
Typewriting machines
Sheet or web
Including friction-feed means
C271S193000, C198S691000, C400S634000
Reexamination Certificate
active
06419411
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a sheet conveying apparatus using a conveyance belt and a recording apparatus incorporating this sheet conveying apparatus and, more particularly, to a sheet conveying apparatus for electrostatically attracting and conveying a recording medium on which images are recorded with recording head in an ink-jet recording apparatus.
2. Description of Related Art
Generally, an ink-jet recording apparatus effects recording by discharging ink onto a recording medium such as paper or a synthetic resin and has advantages such as the recording head can be easily made compact, high resolution images can be recorded with high speed, the running cost can be made inexpensive, the apparatus creates low noise because of its non-impact nature, and color images can be easily recorded using multicolor inks. Particularly, a full-line type apparatus using a line type recording head having multiple orifices arranged in a width direction of the recording medium can record at a higher speed.
With a full-line type apparatus, however, because a distance between a recording head located at the most upstream position and a recording head located at the most downstream position becomes longer, the recording medium may float at the recording area, thereby irregularly forming the recording images, as well as possibly causing paper jamming or the like. Therefore, it is required to pull the recording medium downward so that the recording medium does not float. A method has been known in which conductive electrodes as urging means are provided, to which electric charges are applied to generate electrostatic force, thereby adhering the recording medium made of dielectric material.
In such an ink-jet recording apparatus, the recording medium fed by a feeding apparatus is held to a top surface of the conveyance belt by means of the electrostatic adhering or attracting means formed in the conveyance belt in a recording area for the recording head, and the recording medium is conveyed by the conveyance belt while being recorded by the recording head.
Referring to
FIG. 11
to
FIG. 14
, an example of a conventional ink-jet recording apparatus is described. In
FIG. 11
, the recording sheet P as a recording medium is stacked on a feeding section
51
and fed sheet by sheet from the topmost sheet by a feeding roller
52
.
The recording sheet P thus fed is adhered on a conveyance belt
56
having an adhering force generating means
55
as described below by a driven roller
53
and a pinch roller
54
, and is conveyed to a recording starting position on a platen
58
by a conveyance belt
56
conveyed by a drive roller
57
driven by a pulse motor as a drive source.
The conveyance belt
56
is tensioned with the drive roller
57
, the driven roller
53
, and a pressure roller
59
; one end of the pressure roller
59
is rotatively formed on the other end of an arm
60
formed in a rocking manner to the platen
58
; and the arm
60
applies a tension to the conveyance belt
56
as it is pushed by a spring
61
.
Numeral
62
is a full-line type recording head in which plural recording elements are arrayed across the whole width of the recording area of the recording sheet P. The recording heads
62
are placed with a prescribed interval in the order of
62
K (black),
62
C (cyan),
62
M (magenta), and
62
Y (yellow) and are mounted to a head holder
63
.
FIG. 13
is a plan view of an adhering or attracting force generating means
55
viewed from the top side. In
FIG. 13
, the adhering force generating means
55
formed at the conveyance belt
56
is constituted of comb shaped electrode plates
64
and ground plates
65
made of a conductive metal in which respective teeth are independent from each other, and are disposed alternatingly in a direction perpendicular to the moving direction of the conveyance belt
56
as well as across the recording area of the recording heads
62
.
Voltage receiving portions
64
a
,
65
a
exposing patterns at each edge with respect to the moving direction of the conveyance belt
56
are connected to the electrode plates
64
and the ground plates
65
, and as shown in
FIG. 12
, voltage supplying brushes
66
,
67
serving as voltage supplying means capable of contacting the voltage receiving portions
64
a
,
65
a
are provided over the voltage receiving portions
64
a
,
65
a
, and positive and negative voltages are fed to the electrode plates
64
via the voltage receiving portion
64
a
in contact with the voltage supplying brush
66
, and the ground voltage is fed to the ground plates
65
via the voltage receiving portion
65
a
in contact with the voltage supplying brush
67
.
FIG. 14
is a cross-section taken along section line XIV—XIV shown in FIG.
13
and shows a cross-section of the adhering force generating means
55
formed on the conveyance belt
56
. As shown in
FIG. 14
, the adhering force generating means
55
is protected as the electrode plates
64
and the ground plates
65
are sandwiched by a base layer
56
a
and a surface layer
56
b
constituted of a synthetic resin such as polyethylene, polycarbonate, or the like.
With the above structure, the recording sheets P are attracted to an upper surface of the conveyance belt
56
by the attraction force generating means
55
and conveyed by the conveyance belt
56
while being recorded by the recording heads
62
.
Numeral
68
is a cleaning roller pair for removing stains attached to the conveyance belt
56
and is provided in pressured contact with the conveyance belt
56
. Numeral
69
is a delivery roller and is driven by rotative force of the drive roller
57
via a transmission means (not shown). Numeral
70
is a spur for pressing the delivery roller
69
, and the recording sheet P after recording is nipped by the delivery roller
69
and the spur
70
and delivered to a delivery tray
71
to be contained. The spur
70
has a shape with sharp points such that the recorded image ink is not transferred because the spur
70
runs rotatively on the recording surface after recording.
However, according to the above prior art, because the voltage is fed by the voltage supplying brushes
66
,
67
where the attraction force generating means
55
made of the comb shaped electrodes constituted of the electrode plates
64
and the ground plates
65
is provided on the conveyance belt
56
and where the voltage receiving portions
64
a
,
65
a
are formed as exposed externally on both sides with respect to the conveyance direction of the conveyance belt
56
, inks unexpectedly discharged out of the recording heads
62
, misted ink droplets (ink mist) made of satellites, micro dots, and the like caused by spraying inks, dusts, paper dusts, and so on may be easily attached to the voltage receiving portions
64
a
,
65
a
and the voltage supplying brushes
66
,
67
, and in such a situation, contact between the voltage receiving portions
64
a
,
65
a
and the voltage supplying brushes
66
,
67
becomes unstable, thereby precluding supply of the feeding voltage.
It has been devised that a protection member be provided around the voltage supplying means to isolate it from external portions, but the proposed protection member does not have a structure such that the entire periphery of the conveyance belt is covered thereby, so that substantially the same problems as the above art may arise, such as inks and dusts being attached to the exposed voltage supplying portions.
This invention intends to solve the above problems. It is an object of the invention to provide a sheet conveying apparatus and a recording apparatus having this sheet conveying apparatus capable of protecting the entire voltage receiving portions from inks unexpectedly discharged out of the recording heads, misted ink droplets (ink mist) made of satellites, micro dots, and the like caused by spraying inks, dusts, paper dusts, and so on by covering the entire edges of a conveyance belt formed with the voltage receiving portions by a protection member in a manner so as to isolate thes
Canon Kabushiki Kaisha
Colilla Daniel J.
Fitzpatrick ,Cella, Harper & Scinto
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