Incremental printing of symbolic information – Light or beam marking apparatus or processes – Scan of light
Reexamination Certificate
1997-07-30
2001-10-09
Le, N. (Department: 2861)
Incremental printing of symbolic information
Light or beam marking apparatus or processes
Scan of light
C347S237000, C347S247000
Reexamination Certificate
active
06300969
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recording head of an image recording apparatus, and in particular, to a recording head in which a large number of recording elements, such as LEDs, for generating recording energy are linearly arranged. The recording head of the present invention is preferably used as a recording head in an image recording apparatus, such as a copying machine of an electrophotographic recording system, a facsimile machine and a printer.
2. Related Background Art
Conventionally, in an image recording apparatus for performing image recording by using the electrophotographic recording system, an LED recording head is used. In the LED recording head, a large number of LED light-emitting recording elements, which are respectively radiated in accordance with recording information, are linearly arranged. As a driving system for driving the LED recording head, a matrix driving system is utilized since this driving system can use an inexpensive driving IC.
Such a recording head of a matrix-driving system is disclosed in Japanese Patent Laid-Open Application Nos. 4-348962, 8-156325 and 8-187889, for example.
In a conventional LED recording head of a matrixdriving system, an LED chip including a plurality of LED devices is die-bonded on a glass epoxy substrate, a matrix-wiring pattern is formed on the substrate and the wiring pattern is wire-bonded to an electrode pad of each LED device.
FIG. 1
illustrates an equivalent circuit of the LED recording head of a matrix-driving system. The recording head includes fifty-six (56) LED chips
2
-
1
to
2
-
56
which are linealy arranged. Each of the LED chips
2
-
1
to
2
-
56
respectively includes sixty-four (64) LED elements
2
-
1
-
1
to
2
-
1
-
64
or the like. In each LED chip, LED devices are linearly arranged, and the arrangement direction of those LED devices is coincident with the arrangement direction of the LED chips. The arrangement pitch of the LED devices is approximately 12 pieces/mm, and the recording head is capable of performing recording of an A3 size with a density of 300 DPI (dots per inch).
Anodes of N-th (N=1 to 64) LED devices in the respective LED chips are connected to a common wire and are driven with a constant current by anode drivers
1
-
1
and
1
-
2
. On the other hand, cathodes of sixty-four (64) LED devices in each LED chip are connected in the chip and are succesively driven in a time-sharing manner by cathode drivers
3
-
1
to
3
-
6
. The cathode driver is constructed by six (6) chips each sharing ten (10) channels. Therefore, the matrix-driving of 64×56 can be performed.
FIG. 2
illustrates a plan view of the LED chip
2
-
1
. In the LED devices
2
-
1
-
1
to
2
-
1
-
64
, anode terminals of odd-numbered devices extend to an opposite side to those of even-numbered devices (i.e, the lower and upper sides in
FIG. 2
respectively), and wire bonding pads (WBPs)
4
-
1
-
1
to
4
-
1
-
64
are connected to end portions of the respective anode terminals. Therefore, the arrangement pitch of the WBPs is approximately 6 pieces/mm, and a direct wire-bonding between the WBPs and the wiring pattern formed on an ordinary glass epoxy substrate can be executed.
FIG. 3
illustrates a schematic plan view of the above-discussed LED recording head. Fifty-six (56) LED chips
2
-
1
to
2
-
56
are die-bonded to a central portion of a glass epoxy substrate
5
with respect to a lateral direction and are arranged along a longitudinal direction of the substrate
5
. In regions
15
on both sides of those LED chips, matrix-wiring patterns are formed. The matrix-wiring patterns are is connected to the WBPs of anode terminals of the LED devices in each LED chip by bonding wires (see FIG.
1
). At opposite end portions of the substrate
5
with respect to the longitudinal direction, the above-discussed anode drivers
1
-
1
and
1
-
2
are respectively mounted. One anode driver
1
-
1
is connected so as to drive the above-discussed odd-numbered LED devices, and the other anode driver
1
-
2
is connected so as to drive the above-discussed even-numbered LED devices. That is, though the anode drivers
1
-
1
and
1
-
2
are represented as a unit for sixty-four (64) channels in
FIG. 1
, as a matter of fact those anode drivers
1
-
1
and
1
-
2
are respectively located at different positions with each sharing thirty-two (32) channels. Further, cathode terminals of each LED chip extend to a side of the bottom surface of this LED chip (i.e, the surface of the LED chip which is connected to the glass epoxy substrate
5
), and those cathode terminals are connected to cathode drivers
3
-
1
to
3
-
6
each sharing ten (10) channels.
In such a conventional LED recording head as illustrated in
FIG. 3
, the width of the glass epoxy substrate
5
is approximately 20 mm, and this value is disadvantageous to a recording apparatus which is intended to be made compact by using a small photosensitive drum.
It is possible to obtain a smaller recording apparatus by forming the matrix-wiring as a multi-layer structure, but such a structure is complicated, hence the number of manufacturing steps and cost are increased. Those facts are disadvantageous to the recording apparatus.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a recording head having lower cost and smaller size to solve the above-discussed disadvantages of the prior art technique.
According to one aspect of the present invention, there is provided a recording head in which a recording element array including a plurality of linearly arranged recording elements is arranged, an input of a recording signal into the recording elements is performed through a flexible wiring substrate, and a matrix-wiring for matrix-driving the plurality of recording elements is formed in the flexible wiring substrate.
The following specific configurations can be adopted in the present invention.
The plurality of recording elements are formed into a chip, the chip is mounted onto a first substrate, one end portion of the flexible wiring substrate is bonded to the first substrate and matrixwiring terminals at the one end portion of the flexible wiring substrate are connected to input terminals of the plurality of recording elements formed in the chip by wire bondings.
There are further arranged a support member, a second substrate and a driving element for matrix-driving the plurality of recording elements, the first substrate is mounted onto the support member, the second substrate is mounted onto a side surface of the support member which is approximately perpendicular to a surface of the support member on which the first substrate is mounted, the driving element is mounted onto the second substrate, the other end portion of the flexible wiring substrate is bonded to the second substrate and the other end portion of the flexible wiring substrate is connected to the driving element by a wiring pattern formed on the second substrate.
The flexible wiring substrate is mounted with being bent in an approximately perpendicular form or in an approximately L-shaped form along the support member.
One end portion of the flexible wiring substrate is bonded to the first substrate with thermo-setting adhesive.
The chip is mounted onto the first substrate by using die-bonding.
One part of input terminals of the plurality of recording elements in the chip are arranged on one side with respect to the arrangement of the plurality of recording elements, the other part of input terminals of the plurality of recording elements in the chip are arranged on the other side with respect to the arrangement of the plurality of recording elements, and there are arranged two flexible wiring substrates; one for being connected to the input terminals of the recording elements arranged on the one side and the other for being connected to the input terminals of the recording elements arranged on the other side.
There is formed an additional matrix-wiring in the chip, terminals of the additional matrix-wirin
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Le N.
Nguyen Lamson D.
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