Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-09-18
2001-10-23
Le, N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06305784
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a recorder and a method of making the recorder. In particular, the invention relates to technique for fitting a recording head to a head holder which is used for the recorder like an ink jet printer.
2. Description of Related Art
A known recorder such as an ink jet recorder for recording on a recording medium by ejecting ink onto it includes a head unit, which has recording heads and a head holder. The heads are positioned relative to the holder and fixed to it.
FIGS. 9 and 10
of the accompanying drawings show a conventional head unit
1
′. The unit
1
′ includes a head holder
3
, four recording heads
2
a
,
2
b
,
2
c
and
2
d
, a cartridge case holder
10
, and a head guide
11
. Each of the heads
2
a
-
2
d
includes an actuator provided therein, a manifold
22
and a nozzle plate
23
which are assembled together. The heads
2
a
-
2
d
are positioned relative to the holder
3
, and then fixed to it. The heads
2
a
-
2
d
are connected, each through an FPC (flexible printed circuit)
21
, to a head board
5
. The FPC
21
is soldered to the board
5
, which is connected to the controller of the recorder. The manifold
22
has an ink inlet
22
a
for connection with an ink cartridge case (not shown in
FIG. 9
, but see in
FIG. 6
as reference number
40
). Seal rubbers
8
a
-
8
d
are fitted to the inlets
22
a
of the heads
2
a
-
2
d
, respectively, on the inside of the holder
3
.
After the head unit
1
′ is assembled, one or more of the recording heads
2
a
-
2
d
may be defective. If the heads
2
a
-
2
d
are bonded to the head holder
3
, it is not possible to replace only a defective recording head. A printing test may be carried out with the unit
1
′ fitted to the recorder. If the test reveals that even one of the heads
2
a
-
2
d
is defective, it is necessary to replace the whole unit
1
′. In addition, because the FPCs
21
for the heads are soldered to the head board
5
, it is very difficult to tear off the FPC for the defective head and solder the FPC for the substituted head.
SUMMARY OF THE INVENTION
In view of the foregoing problems, it is an object of the invention to provide a recorder of which a defective recording head can be replaced and a substituted head can be positioned accurately with respect to the head holder, in particular, to provide a recorder with a plurality of recording heads among which only one defective recording head can be easily replaced and repositioned with respect to the head holder and the other recording heads with high positional accuracy.
It is another object of the invention to provide a method of making such a recorder.
In accordance with a first aspect of the invention, a recorder is provided for recording on a recording medium by ejecting ink onto it. The recorder includes a head holder, an intermediate member fitted removably to the holder, and a recording head fixed to the member.
After the head holder, the intermediate member and the recording head are assembled into a head unit, or after the unit is fitted to the recorder, head trouble may be found. Even in such a case, because the member can be removed from the holder, it is possible to remove the defective head together with the member, fit a new intermediate member to the holder, position a new recording head relative to the holder through the intermediate member in a certain manner described later on, and fixed the positioned head to the new member. Therefore, the holder can still be used effectively without being useless. It is possible to position the head relative to the holder simply by positioning the head relative to the member. It is therefore easier to position the head than if the head is screwed directly to the holder. It is conceivable that the heads may be fixed with screws direct to the head holder. Namely, if the heads are screwed to the holder, replacement of only a defective recording head is still possible. However, when a new recording head is substituted, it may be dislocated or displaced by the screwing torque relative to the head holder. It is therefore difficult to directly mount the heads or the substituted head onto the holder with high positional accuracy by using the screw.
The intermediate member may have such structure that the recording head can be fixed to the member while the head is positioned relative to the member. Specifically, the member may have a hole engaging with part of the head with play. This makes it possible to position the head relative to the member before the head is fixed to the member. In this case, it is easy to position the head relative to the head holder. The member may be screwed to the holder. This makes it easy to fit the member to and remove the member from the holder.
In accordance with a second aspect of the invention, another recorder is provided for recording on a recording medium by ejecting ink onto it. This recorder includes a head holder, intermediate members fitted removably to the holder, and a plurality of recording heads each fixed to one of the members.
After the head holder, the intermediate members and the recording heads are assembled into a head unit, or after the unit is fitted to the recorder, one of the heads may be found to be defective. Because the members can be removed from the holder, it is possible to remove only the defective head together with the associated member, fit a new intermediate member to the holder, position a new recording head accurately with respect to the holder and the other heads, and fix the positioned head to the new member. Therefore, even if part of the heads are defective, the other heads and the holder can still be used. Because the normal heads are positioned already, the unit can be reassembled and fitted to the recorder again in a short time. Therefore, this recorder is very effective for dot matrix type recording heads.
The recording heads may be ink jet heads. In general, the dot pitch of an ink jet recorder is very fine (in general, 0.1 or less mm). Even slight dislocation of the ink jet heads of an ink jet recorder affects the recording quality. It is therefore necessary to position the heads relative to each other with high accuracy. By using the intermediate members of the invention, it is easy to position the heads, and there is no need to position normal heads again. Therefore, the invention is very useful for ink jet recording. The ink jet heads of the invention may each include a nozzle plate, an actuator having ink chambers and a manifold having an ink inlet. The intermediate members may each have a hole engaging with the manifold of the associated head. Each of the heads may be bonded with an adhesive to the associated member. The members may be screwed to the head holder. The members may be made of the same material as the holder so that each member has the same coefficient of thermal expansion. This prevents the members from being dislocated.
The recorder according to the second aspect may also include a controller for controlling the recorder and a circuit board for driving the recording heads. The board is connected to the controller. Each of the heads may be connected to the board disconnectably through a connector. In this case, if one of the heads is defective, it can be disconnected easily from the board in order to be replaced.
In accordance with a third aspect of the invention, a method of making a recorder is provided. The recorder includes a recording head for recording on a recording medium by ejecting ink onto the medium. The head is positioned relative to a head holder and fixed to it. The method comprises the steps of:
fitting removably to the holder an intermediate member for supporting the head;
positioning the head relative to the holder; and
fixing the positioned head to the member.
This recording head may include a plurality of heads. This intermediate member may include plates each associated with one of the heads. Each of the heads may be positioned relative to the head holder and then be fixed to the
Brother Kogyo Kabushiki Kaisha
Le N.
Nghiem Michael
Oliff & Berridg,e PLC
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