Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1996-11-14
2001-07-10
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06257707
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an electrode board for an image forming apparatus for obtaining an image by controlling the passage of toner particles in a device such as a copier, printer, facsimile and other equipment.
2. Description of Related Art
A conventional image forming apparatus for obtaining an image is disclosed in Japanese Unexamined Patent Publication No. 6-155798 (1994). In this conventional image forming apparatus, an image signal is applied as a drive signal to an aperture-electrode board having a plurality of small holes each called an aperture. The passage of toner particles through the apertures is controlled so that an image is obtained on an image recording medium such as printing paper.
In such an image forming apparatus, a toner carrying roller
102
and an image recording medium
103
are installed so as to face each other, sandwiching an aperture-electrode board
101
, as shown in
FIG. 4. A
back electrode roller
104
is further installed so as to abut the back surface of the image recording medium
103
. In the aperture-electrode board
101
, a plurality of apertures
106
each having a relatively small diameter are formed in the longitudinal direction of the aperture-electrode board
101
on a flexible printed circuit board (FPC)
105
formed from a thin sheet made of a polyimide material. A copper foil serving as a control electrode
107
is formed around each of the apertures
106
. The aperture-electrode board
101
is fixed to a toner case
111
. A control voltage based on an image signal is applied from a control-voltage generating circuit
112
to each control electrode
107
in order to control a flow of toner
113
supplied by the toner carrying roller
102
for creating an image on the image recording medium
103
.
Circuit devices
115
such as IC chips for controlling a drive signal, that is, the control voltage applied to the control electrodes
107
, are also provided on the flexible printed circuit board
105
to form an assembled single body. The assembled single body includes wiring on the flexible printed circuit board
105
for electrically connecting the numerous control electrodes
107
and the circuit devices
115
. Normally, the electrical connection is implemented by wires
116
by means of a wire bonding technique as shown in FIG.
5
.
In order to implement a number of circuit devices
115
by using the wire bonding technique, however, the manufacturing processes entail a high cost. In addition, with the circuit device
115
electrically connected by means of the wire bonding technique, a molding
108
made of silicon resin is required to cover the circuit device
115
and the wires
116
as shown in FIG.
6
. As a result, the mounting area of the circuit device
115
becomes a relatively great size, making it difficult to implement miniaturization of the apparatus. Further, an attempt made to increase the image resolution will decrease the pitch of the electrical wiring, making the work to electrically connect the circuit device
115
by using the wire bonding technique difficult to carry out.
In addition, in order to prevent a wire
116
from being broken and wires
116
adjacent to each other from being brought into contact with each other, the molding
108
is implemented as shown in
FIG. 6
when the circuit device
115
is electrically connected by means of the wire bonding technique. Accordingly, the height of the circuit device
115
as measured from the flexible printed circuit board
105
is increased by the molding
108
. As a result, when the completed aperture-electrode board
101
is mounted on a printing apparatus like the one shown in
FIG. 4
, the distance from the aperture-electrode board
101
to the image recording medium
103
is increased. In consequence, the distance traveled by a flow of toner from the toner carrying roller
102
to the image recording medium
103
through the apertures
106
on the aperture-electrode board
101
is also increased. As a result, it is difficult to control the flow of toner so as to apply the toner to the image recording medium with a high degree of reliability, giving rise to a problem that a good image can not be obtained.
By the same token, since the circuit device
115
such as an IC chip itself is provided on the flexible printed circuit board
105
with the upper surface thereof exposed, dust and dirt are inadvertently stuck to the circuit device
115
during the manufacturing processes, making it impossible to control the control electrodes
107
with a sufficient degree of accuracy. In addition, if the circuit device
115
is touched by mistake, it is feared that the circuit device
115
is damaged.
SUMMARY OF THE INVENTION
The invention addresses the problems described above. It is thus an object of the invention to provide an electrode board for an image forming apparatus, which allows a plurality of circuit devices to be connected electrically to a plurality of control electrodes on an electrode circuit board in a single process, can keep up with a reduced wiring pitch with ease, allows the manufacturing cost to be reduced, can cope with a small mounting area, allows the size of the electrode circuit board to be reduced and allows the resolution to be enhanced.
In order to achieve the object described above, an electrode board for an image forming apparatus according to a first aspect of the invention comprises: an electrode circuit board; a plurality of charged-particle passing units created on the electrode circuit board; a plurality of control electrodes each provided for each of the charged-particle passing units, each control electrode being used for supplying particles to be electrically charged by the charged-particle passing unit and for controlling the passage of the charged particle; and a back electrode for attracting charged particles passing through the charged-particle passing units, wherein circuit devices for controlling a drive signal applied to the control electrodes are mounted on the electrode circuit board by means of a flip-chip method.
In the configuration described above, since the circuit device is mounted on the electrode circuit board by using the flip-chip method, a plurality of circuit devices can be mounted on the electrode circuit board with ease even if the board is flexible in comparison with the mounting technique based on the wiring bonding. On the top of that, the electrode board can keep up with a small pitch and allows circuit devices to be mounted at a high mounting density.
According to an electrode board for an image forming apparatus in a second aspect of the present invention, in the above electrode board for an image forming apparatus, each of the circuit devices is turned upside down and connected electrically to the wiring on the electrode circuit board through protrusions. With this configuration, a number of circuit devices can be connected to the wiring on the electrode circuit board in a single assembly process, allowing the wiring work to be done with ease.
According to the electrode board for an image forming apparatus provided by the present invention as described above, since a circuit device is mounted on an electrode circuit board by means of a flip-chip method, the circuit device can be electrically connected to a control electrode with ease in comparison with the conventional mounting technique based on the wiring bonding. As a result, the aperture-electrode board allows the manufacturing cost to be reduced, can cope with a small mounting area and allows the size of the electrode circuit board to be reduced. On the top of that, the aperture-electrode board can keep up with a reduced electrical-wiring pitch with ease and allows the resolution to be enhanced.
In addition, since each of the circuit devices is turned upside down and connected electrically to the wiring on the electrode circuit board through protrusions, a number of circuit devices can be connected to the wiring on the electrode circuit board in a single assembly process, allowing the effects
Barlow John
Brooke Michael S
Brother Kogyo Kabushiki Kaisha
Oliff & Berridg,e PLC
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