Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-03-23
2001-09-11
Gordon, Raquel Yvette (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06286936
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to copiers, facsimiles and printers, more particularly to an image forming apparatus and an image forming method for spraying toner to a recording member for carrying out recording.
Large amounts of documents have recently begun to be treated in offices in accordance with improvement in the performance of personal computers. Furthermore, printers and copiers having high processing capabilities come into wide use in accordance with progress in network technology. In addition, colored documents tend to increase in number in accordance with the abrupt widespread use of ink jet and the like printers. However, apparatuses capable of outputting monochrome documents and colored documents in satisfactory conditions, e.g. at high speed, are now in the course of development, and the advent of such apparatuses is waited for at present.
Prior art will be described below referring to the accompanying drawings.
FIG. 8
is a schematic sectional view showing an electric signal recording apparatus disclosed in the Japanese published examined patent application, Publication No. Sho 44-26333.
Referring to
FIG. 8
, toner
75
is negatively charged for example by friction with fur at the rotation of a brush
76
. A power source
77
is connected across a mesh electrode
74
and a back electrode
71
to generate an electric field for accelerating the charged toner
75
toward a recording member
72
.
When an electric signal
78
responding to image information is applied across the mesh electrode
74
and a control grid
73
in the above-mentioned electric field generation condition, the amount of the toner
75
passing through the mesh electrode
74
and the adhesion position of the toner
75
to the recording member
72
can be controlled responding to the polarity and intensity of the applied electric signal
78
. A parallel electric field for accelerating the toner
75
toward the recording member
72
is generated between the mesh electrode
74
and the back electrode
71
by the power source
77
.
When an “on” signal (a positive signal in case the toner
75
is negatively charged) is used as the electric signal
78
and applied to the control grid
73
, a gate is opened, and the toner
75
moves toward the recording member
72
along the parallel electric field. On the other hand, when an “off” signal (a negative signal in case the toner
75
is negatively charged) is used as the electric signal
78
and applied to the control grid
73
, the gate is closed, and the toner
75
cannot pass through the control grid
73
. In this way, images are recorded in accordance with the combination of the “on” and “off” signals used as the electric signal
78
.
FIG. 9
is a sectional view showing a schematic configuration of another image recording apparatus disclosed in the Japanese published examined patent application, Publication No. Hei 2-52260. Referring to
FIG. 9
, a signal electrode
101
and a base electrode
103
are formed around a hole
104
with an insulator
102
disposed therebetween. A recording member
105
, e.g. a paper, moves on the surface of a back electrode
106
disposed opposite to the signal electrode
101
. The back electrode
106
is connected to a DC power source
109
, and a voltage of about 300 V is applied to the back electrode
106
. One-component insulating magnetic toner
111
is transferred from a toner transfer member
107
to an image forming position.
An AC power source
108
is connected across the toner transfer member
107
and the base electrode
103
. A signal source
110
is connected to the signal electrode
101
and the base electrode
103
, and a recording voltage of 50 V is applied to the electrodes
101
and
103
. Referring to
FIG. 9
, the toner transfer member
107
is provided with a stationary magnet
112
, and a magnetic blade
114
is provided in the vicinity of the toner transfer member
107
.
Next, the image forming operation in the conventional image forming apparatus shown in
FIG. 9
will be described below. Thin layers of the one-component insulating magnetic toner
111
are formed on the toner transfer member
107
by the magnetic blade
114
. When an AC signal on which an AC or DC signal is superimposed is applied across the base electrode
103
and the toner transfer member
107
, the one-component insulating magnetic toner
111
begins a reciprocating or vibrating motion. When a recording signal is input to the signal electrode
101
, the one-component insulating magnetic toner
111
passes through the hole
104
, and adheres to the recording member
105
in accordance with an electric field applied to the back electrode
106
.
As a result, an image is formed on the recording member
105
. On the other hand, when no voltage is applied to the signal voltage
101
, or when a voltage with the opposite polarity is applied, the one-component insulating magnetic toner
111
does not pass through the hole
104
, and no image is formed.
However, the above-mentioned conventional image recording apparatuses have the following problems.
(1) First, a problem is described below, which is encountered in a conventional image forming apparatus disclosed in the Japanese published examined patent application, Publication No. Sho 44-26333 and shown in
FIG. 8
, wherein the parallel electric field generated between the mesh electrode
74
and the back electrode
71
is controlled by an electric signal applied to the control grid
73
. In the case of this kind of conventional image forming apparatus, a sufficient distance is required to be provided between the mesh electrode
74
and the control grid
73
so that the open/close signal generated by the control grid
73
functions sufficiently. However, if a large distance is provided between the mesh electrode
74
and the control grid
73
, the toner
75
to be sprinkled is less controllable, whereby proper images cannot be obtained.
Furthermore, in the case of this kind of image forming apparatus, the toner
75
is sprinkled around the apparatus, whereby the basic performance of the apparatus is not satisfactory. Conversely, if the mesh electrode
74
is disposed so as to be close to or make contact with the control grid
73
, signals having a large voltage difference must be used as electric signals. This requires the use of a switching device suited for high-voltage switching. For this reason, it is inevitable that this kind of image forming apparatus becomes larger in size and higher in cost.
(2) In such a system disclosed in the Japanese published examined patent application, Publication No. Hei 2-52260 and shown in
FIG. 9
, wherein the signal electrode
101
and the base electrode
103
are formed on both sides of the insulating member
102
, the lines of electric forces for jumping the toner
111
are intensely generated between the signal electrode
101
and the base electrode
103
. For this reason, the toner
111
is liable to adhere to an inner wall surface forming the hole
104
, and the hole
104
is liable to be clogged with the toner
(3) Furthermore, in the system wherein the signal electrode
101
and the base electrode
103
are formed on both sides of the insulating member
102
, the lines of electric forces are generated between the two electrodes at all times. Therefore, the toner
111
is liable to adhere to the inner wall surface of the hole
104
. This requires another means for eliminating the toner
111
adhered to the hole
104
.
BRIEF SUMMARY OF THE INVENTION
Accordingly, an image forming apparatus in accordance with the present invention comprises at least:
charging means for charging particles to form charged particles;
charged particle transfer means for transferring charged particles and made of a conductive material;
a back electrode for receiving charged particles directly or indirectly;
an aperture electrode disposed between the charged particle transfer means and the back electrode, having a plurality of openings, and also having a plurality of control electrodes being independent from each other and each formed ins
Aizawa Masahiro
Fukano Akira
Kitaoka Yoshitaka
Kumon Akira
Matsuo Hiroyuki
Akin, Gump, Strauss, Hauer & Feld, L.P.
Array Aktiebolag
Gordon Raquel Yvette
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